CN104237620A

CN104237620A - Voltage detection device

Info

Publication number: CN104237620A
Application number: CN201410347401.4A
Authority: CN
Inventors: 柳泽浩一
Original assignee: Hioki EE Corp
Current assignee: Hioki EE Corp
Priority date: 2009-04-30
Filing date: 2010-04-28
Publication date: 2014-12-24
Anticipated expiration: 2030-04-28
Also published as: CN104237620B

Abstract

The voltage detector of the invention is a device for detecting detection object alternating currents generated in a detection object. The voltage detector includes: a detecting electrode arranged in opposition to a detection object; a detecting section that is connected with the detecting electrode to use the reference signal as an input for outputting a detection signal changing its amplitude in accordance with both current values of a detection object current flowing according to the AC voltage and a reference current flowing according to the reference signal; and a signal extraction section for extracting a signal component of the voltage from an amplified detection signal and outputting the signal component as an output signal while generating the amplified detection signal by amplifying an isolated detection signal of a detection signal at a given gain and controlling the gain so as to cancel the reference signal and a signal component of the reference signal included in the amplified detection signal by addition or subtraction of the reference signal (reference signal output from a reference signal output section) and the amplified detection signal.

Description

Voltage check device

(the application is: apply for artificial Zhi Electric Co., Ltd, Chinese application number is 201010173890.8, the applying date is on 04 28th, 2010, is entitled as the divisional application of " voltage check device ".)

The right of priority that this application claims is the application number that the application number that the application number that the application number that the application number submitted on April 30th, 2009 is 2009-110304, on May 13rd, 2009 submits to is 2009-116546, on July 21st, 2009 submits to is 2009-169731, on August 3rd, 2009 submits to is 2009-180785, on March 25th, 2010 submits to is 2010-69677, on March 25th, 2010 submits to application number be the application number that 2010-69695 and 2010 submits to 25, on March is the Japanese patent application of 2010-69714, and its content is incorporated in this by reference.

Technical field

What the present invention relates to is non-contactly to the voltage check device of the non-contact type that the detected object alternating voltage of detected object detects.

Background technology

As this voltage check device, known has patent documentation 1: Japan, the non-contact voltage measurement mechanism (hereinafter also referred to as " voltage check device ") of special permission disclosed in No. 3158063 publication (4-6 page, Fig. 3).This voltage check device is provided with: having can by the detecting electrode of a part of surface coverage of the insulant of electric wire and by the detector probe (sensing probe) of the guarded electrode of detecting electrode covering, with the oscillator of the signal of output assigned frequency, by the signal of oscillator is additional to detecting electrode, and the impedance of measuring between detecting electrode and the conductor of electric wire, and use detection resistor (resistance value: R1) and measure the electric current flowed out from detecting electrode caused because of the voltage be additional on conductor, thus can measure from electric current and impedance the voltage be affixed to conductor.

Specifically, in this voltage check device, first, opening detector probe and under the state being additional on detecting electrode via the signal of detection resistor in the future self-oscillator, carry out the measurement of the electrostatic capacitance (following, to be called to illustrate " the first electrostatic capacitance ") between guarded electrode and ground connection.Due to resistance value little degree to ignoring compared with the reactance of the first electrostatic capacitance of detection resistor, the first electrostatic capacitance therefore obtained by this measurement calculates from the resistance value of the signal voltage exported by oscillator, detection resistor, the angular frequency of signal exported by oscillator and the both end voltage of detection resistance.

Then, clamping electric wire and close detector probe, carrying out the measurement of the electrostatic capacitance (following, to be called to illustrate " the second electrostatic capacitance ") under the state being additional to detecting electrode via the signal of detection resistor self-oscillator in future.By like this, the second electrostatic capacitance measured, become the first above-mentioned electrostatic capacitance and the electrostatic capacitance between detecting electrode and electric wire (following, be called to illustrate " the 3rd electrostatic capacitance ") equivalent capacity, resistance value due to detection resistor compares the little degree to ignoring of reactance of this equivalent capacity, and therefore the second electrostatic capacitance is calculated from the resistance value of the signal voltage exported by oscillator, detection resistor, the angular frequency of signal exported by oscillator and the both end voltage of detection resistance.In addition, by deducting above-mentioned first electrostatic capacitance from the second electrostatic capacitance calculated, and the 3rd electrostatic capacitance is calculated, the electrostatic capacitance namely between detecting electrode and the conductor of electric wire.

Then, clamp electric wire and close detector probe, obtain the both end voltage of detection resistor under the state that the signal via detection resistor in the future self-oscillator is additional to detecting electrode, that cause because of the voltage be affixed on conductor.The impedance of the circuit via detection resistor observed from conductor side, it is the addition calculated value of the resistance value of detection resistor and the reactance of the 3rd electrostatic capacitance, but, due to resistance value little degree to ignoring compared with the reactance of the 3rd electrostatic capacitance of detection resistor, therefore above-mentioned impedance becomes the reactance of the 3rd electrostatic capacitance.By like this, because the electric current circulated in detection resistor becomes, the voltage be additional on conductor is carried out the value after except calculation with this reactance, therefore the both end voltage of detection resistor, become the electric current circulated in detection resistor be multiplied by the resistance value of detection resistor after value.In this situation, the both end voltage of this detection resistor, by be additional to the angular frequency of the voltage on conductor, the 3rd electrostatic capacitance between detecting electrode and electric wire, be additional to the resistance value of voltage on conductor and detection resistor each parameter and be expressed.Therefore, in voltage check device, to the voltage on conductor be additional to, and calculate from the resistance value of the angular frequency of the both end voltage of detection resistor, the voltage be additional to conductor, the 3rd electrostatic capacitance between detecting electrode and electric wire and detection resistor, and be shown in display part.

Summary of the invention

But, in above-mentioned voltage check device, there is following problem points.Namely, in this voltage check device, must calculate the electrostatic capacitance (above-mentioned first electrostatic capacitance) between guarded electrode and ground connection and the electrostatic capacitance between detecting electrode and the conductor of electric wire (above-mentioned 3rd electrostatic capacitance) respectively, therefore there is the detection operation being additional to voltage on conductor wastes time and energy such problem points.

The present invention is suggested to solve the problem, its object is to provide a kind of electrostatic capacitance without the need to calculating between detecting electrode and detected object (being the conductor of electric wire in above-mentioned example), and the voltage check device of the non-contact type of the voltage of detected object can be detected.

Adopt words of the present invention, a kind of voltage check device detecting the detected object alternating current produced in detected object can be provided, it is characterized in that, be provided with: detecting electrode, contrast signal efferent, test section and signal extraction portion, wherein, detecting electrode is relative with detected object and arrange and carry out capacitive coupling with this detected object, contrast signal efferent exports contrast signal, test section is connected to detecting electrode, simultaneously, input contrast signal by according to detected object electric current with the detection signal of amplitude variations exports with reference to two current values of electric current, above-mentioned detected object electric current is the electric current circulated according to detected object alternating voltage, above-mentioned is the electric current circulated according to contrast signal with reference to electric current, it is such that signal extraction portion becomes setting with the amplitude of the signal content making the contrast signal comprised in detection signal, and ride gain amplification detection signal, the signal content of detected object alternating voltage is extracted from the amplification detection signal that its result obtains, and export as output signal.

Signal extraction portion can be provided with, to pass through from the contrast signal of contrast signal efferent output and adding or subtracting calculation of this amplification detection signal, the signal content of the contrast signal this contrast signal and this amplification detection signal comprised offsets the control circuit of ride gain like that, with the signal that the signal content of the contrast signal comprised by this signal from amplification detection signal is cancelled, as the signal content of detected object alternating voltage and the circuit exported.

In such formation, test section is while being connected to and carrying out on capacity coupled detecting electrode with detected object, from contrast signal efferent input contrast signal, and the detected object electric current that basis is circulated based on the detected object alternating voltage of detected object and the detection signal output of amplitude variations based on two current values with reference to electric current of contrast signal circulation, signal extraction portion by detection signal with regulation gain amplify and while generating amplification detection signal, to pass through from the contrast signal of contrast signal efferent output and adding or subtracting calculation of amplification detection signal, and the signal content of the contrast signal that can comprise with reference to signal and amplification detection signal offsets such ride gain, the signal content of detected object alternating voltage extracted from amplification detection signal simultaneously and export as output signal.

In this situation, on the current path comprising the coupling capacitance between detected object and detecting electrode (electrostatic capacitance), circulation has the electric current produced by contrast signal and the electric current produced by detected object alternating voltage, forms detection signal by the voltage component (signal content of contrast signal and the signal content of detected object alternating voltage) based on two electric currents.

Therefore, even if voltage check device due to the coupling capacitance between detected object and detecting electrode be unknown, sensitivity for detected object alternating voltage is also controlled as and becomes fixing sensitivity, that is the amplitude outputing signal the signal content of the detected object alternating voltage comprised is controlled as and becomes the size corresponding with the amplitude of detected object alternating voltage, therefore, by detecting this voltage component that output signal comprises, also detected object alternating voltage can be detected non-contactly without the need to carrying out calculating of coupling capacitance.

In addition, in addition, signal extraction portion also can be provided with, and becomes the prespecified fixed value control circuit of ride gain like that with setting.

In such formation, test section is while being connected to and carrying out on capacity coupled detecting electrode with detected object, from contrast signal efferent input contrast signal, and the detection signal of the detected object electric current that circulates and two current values with reference to electric current that circulate based on contrast signal and amplitude variations according to the detected object alternating voltage based on detected object is exported, signal extraction portion by detection signal with regulation gain amplify and while generating amplification detection signal, the amplitude of the signal content of the relevant contrast signal comprised with amplification detection signal becomes fixing such ride gain, the signal content of detected object alternating voltage extracted from amplification detection signal simultaneously and export as output signal.

In this situation, on the current path comprising the coupling capacitance between detected object and detecting electrode (electrostatic capacitance), circulation has the electric current caused by contrast signal and the electric current caused by detected object alternating voltage, forms detection signal by the voltage component (signal content of contrast signal and the signal content of detected object alternating voltage) based on two electric currents.

Therefore, voltage check device, the amplitude of the signal content of the contrast signal comprised with amplification detection signal due to signal processing part becomes the fixing gain that controls like that for Insulation monitoring signal and generates amplification detection signal, even if the coupling capacitance therefore between detected object and detecting electrode is unknown (capacitance regardless of coupling capacitance), the sensitivity of the signal content of the related detection object exchange voltage comprised in amplification detection signal is also controlled as and becomes fixing sensitivity, that is, the amplitude of the signal content of the detected object alternating voltage comprised in output signal is controlled as and becomes the size corresponding with the amplitude of detected object alternating voltage, therefore, according to the amplitude of the output signal be made up of the signal content of this detected object alternating voltage, can correctly detect detected object alternating voltage.Therefore, this voltage check device can save the time and efforts (without the need to carrying out calculating of coupling capacitance) of the coupling capacitance (electrostatic capacitance) calculated between detected object and detecting electrode, and detects detected object alternating voltage non-contactly.

And then the judging part that execution two judges at least one the judgement process in process can be provided with, wherein, these two judgements are treated to: the level detecting the signal content of the contrast signal that any one signal in detection signal and amplification detection signal comprises, simultaneously, be judged as that when the level that this detects is more than specified level action judges process normally, and be judged as the judgement process of remarkable action when the level that this detects is less than this specified level.

Under the state of voltage check device normally action, when detecting electrode and detected object carry out capacitive coupling, the current component produced by the contrast signal that exports from contrast signal efferent circulates between detected object and test section, thus becomes the signal content produced by this current component and be often contained in state in detection signal etc. and amplification detection signal.By like this, calculated in advance as specified level by the lower limit of the level of the signal content (signal content produced by contrast signal) using the contrast signal comprised in detection signal during this regular event etc. or amplification detection signal as an example, thus while the level of the signal content of the relevant contrast signal comprised in any one signal in detection signal etc. and amplification detection signal by judging part detected, perform and be judged as that when the level that this detects is in specified level action judges process normally, with at least one process be judged as when the level that this detects is less than specified level in the judgement process of remarkable action, the result that operator can process according to this judgement, the detection carrying out the voltage in voltage check device operates the diagnosis (judgement) whether normally carried out.

In addition, due to the detected object alternating voltage that operator can be made to distinguish detect be action normal time voltage or remarkable action time voltage, therefore, it is possible to improve the reliability for the detected object alternating voltage detected.

And then can power supply unit be provided with, the floating voltage that it is reference voltage with the contrast signal from contrast signal efferent that this power supply unit passes through, and drive test section.

Signal extraction portion can be provided with: amplifying circuit, synchro detection circuit, control circuit; Wherein, detection signal amplifies and generates amplification detection signal by amplifying circuit, synchro detection circuit is by employing the synchronous detection of the contrast signal exported from contrast signal efferent, and detecting the rectified signal of the amplitude of the signal section representing the contrast signal comprised in this amplification detection signal or output signal, control circuit controls the gain of amplifying circuit according to rectified signal.

Owing to correctly can be detected the signal content of contrast signal by synchronous detection, therefore, it is possible to detect rectified signal accurately.Thereby, it is possible to be fixing by the amplitude controlling of the signal content of detected object alternating voltage comprised in output signal accurately, thus the accuracy of detection of detected object alternating voltage can be improved further.

When being driven test section by floating voltage, and then can be provided with by under the state of test section and signal extraction portion electrical isolation, detection signal is sent to the insulation division in signal extraction portion from test section.

By using such as guard electrode as reference voltage portion; and can detecting electrode, floating power supply, test section and insulation division be contained in this guard electrode; and action under quick condition, therefore, it is possible to improve CMRR (Common Mode Rejection Ratio, common mode rejection ratio).

Owing to driving test section by floating voltage, therefore power supply unit is provided with, and this power supply unit can as the formation supplying each floating voltage to test section, wherein, above-mentioned power supply unit has the first series-connection power supplies circuit and the second series-connection power supplies circuit, first series-connection power supplies circuit is according to this positive voltage be supplied in the positive voltage in contrast signal efferent and signal extraction portion and negative voltage, and generation is the first floating voltage of fixing positive voltage relative to the voltage of contrast signal, second series-connection power supplies circuit is according to negative voltage, generating relative to the voltage of contrast signal is the second floating voltage that absolute value equals the negative voltage of the first floating voltage.

By adopting such formation, the high price parts using accumulator or transformer etc. can be avoided, consequently can reduce cost of products significantly.

First series-connection power supplies circuit can be provided with: be connected to the first resistance of positive voltage, carry out the first voltage stabilizing diode of action from the supply of this first resistance received current, and the first transistor, the collector terminal of this first transistor is connected to positive voltage, simultaneously, base terminal is transfused to the voltage of voltage regulation of the first voltage stabilizing diode, and on emitter terminal, generates the first floating voltage; Second series-connection power supplies circuit can be provided with: be connected to the second resistance of negative voltage, carry out the second voltage stabilizing diode and the transistor seconds of action from the supply of this second resistance received current, the collector terminal of this transistor seconds is connected to negative voltage, simultaneously, base terminal is transfused to the voltage of voltage regulation of above-mentioned second voltage stabilizing diode, and on emitter terminal, generates above-mentioned second floating voltage.

By being made up of the first series-connection power supplies circuit and the second series-connection power supplies circuit respectively resistance, voltage stabilizing diode and transistor, and can with few parts number of packages, simply and formed each series-connection power supplies circuit at an easy rate.

In order to the signal that is cancelled with reference to the signal content of the signal signal content as detected object alternating voltage extracts, signal extraction portion can be provided with adding circuit or subtraction circuit, wherein, adding circuit is by adding, the signal content of the contrast signal exported from contrast signal efferent and contrast signal is offset and output signal output, the signal content of the contrast signal exported from contrast signal efferent and contrast signal, by subtracting calculation, is offset and output signal output by subtraction circuit.

Adopt this formation, can by the circuit that can be made up of simply adding circuit or the such circuit of subtraction circuit, offset with reference to the signal section of signal and contrast signal and output signal is exported.Therefore, it is possible to while the simplification seeking device formation, positively output signal output.

In order to from amplification detection signal extraction at least with reference to the signal content that the frequency content of signal removes, signal extraction portion can be provided with by the signal content of detected object alternating voltage from amplification detection signal extraction and export wave filter.

By adopting the formation using wave filter from the signal content of amplification detection signal extraction detected object alternating voltage, can be simultaneously simple in formation, with low cost generating output signal.

In order to control the gain for the detection signal in signal extraction portion, can be provided with and the amplitude of the contrast signal exported from contrast signal efferent is changed and the amplitude changing unit exported to signal extraction portion.

Adopt the words of this formation, when the amplitude of the contrast signal after making change is k relative to the multiplying power of the amplitude of contrast signal before changing, by making the amplitude of the output signal be made up of the signal content of detected object alternating voltage be 1/k times, and detected object alternating voltage can be detected.Therefore, by changing this multiplying power k, the sensing range of detected object alternating voltage can be expanded.

And then, can be provided with according to outputing signal the handling part detected detected object alternating voltage.Adopt this formation, such as, can detect detected object alternating voltage at certain intervals to handling part, maybe the detected object alternating voltage detected is shown in display device etc. as waveform, thus can convenience be improved.

In this situation, handling part can calculate the magnitude of voltage of detected object alternating voltage according to output signal.By like this, (measurement) detected object alternating voltage correctly can be detected.

Contrast signal efferent, the square wave generative circuit that is provided with and generates square wave can be adopted and using this square wave integration as the formation of integrating circuit that integration square wave exports, wherein, integration square wave is exported by test section as contrast signal, and square wave is exported by signal extraction portion as contrast signal.

Adopt the words of this formation, square wave generative circuit is formed simply by using logical circuit etc., can making the formation of contrast signal efferent entirety become simple while, make the reference electric current circulated based on contrast signal, become the square wave identical with the square wave exported to signal extraction portion from contrast signal efferent.By like this, while simple formation can being formed as being formed by device (being specially the formation of contrast signal efferent entirety), in signal extraction portion, positively can offset (elimination) with reference to the signal section of the contrast signal comprised in signal and amplification detection signal, thus the signal content of detected object alternating voltage positively can be extracted from amplification detection signal and export as output signal.

In addition, contrast signal efferent is provided with the pseudo noise generative circuit generating pseudo noise, and pseudo noise also can as contrast signal by the formation exported to test section and signal extraction portion.

By using pseudo noise as contrast signal, the impact being difficult to be disturbed (noise) can be become.

Multiple voltage check device of the present invention can be used, form line voltage distribution pick-up unit.That is, the multiple voltage check devices to detecting as the alternating voltage produced respectively in multiple circuit of detected object can be provided with, with the differential voltage calculating the alternating voltage detected by multiple voltage check device, thus obtain the calculating section of the line voltage distribution between multiple circuit, as multiple voltage check device, use above-mentioned voltage check device respectively.

Even if when as detected object circuit and to should the coupling capacitance between the detecting electrode of circuit be unknown, also without the need to calculating the coupling capacitance (electrostatic capacitance) between circuit and detecting electrode, and can noncontact and line voltage distribution correctly between detection line.

Accompanying drawing explanation

At this, with reference to the following drawings, specific embodiment of the invention form is shown and to be described with example.

Fig. 1 is the structural drawing of the voltage check device that the first example of the present invention relates to.

Fig. 2 is the circuit diagram in the floating circuit portion in voltage check device shown in Fig. 1.

Fig. 3 is the circuit diagram of the amplifying circuit in voltage check device shown in Fig. 1.

Fig. 4 is the structural drawing of the voltage check device that the second example of the present invention relates to.

Fig. 5 is the circuit diagram of the test section in voltage check device shown in Fig. 4.

Fig. 6 contrast signal efferent that can replace in voltage check device shown in Fig. 1 or Fig. 4 uses, from the block diagram of other the different contrast signal efferents shown in Fig. 1 and Fig. 4.

Fig. 7 contrast signal efferent that can replace in voltage check device shown in Fig. 1 or Fig. 4 uses, from the block diagram of other the also different contrast signal efferents shown in Fig. 6.

Fig. 8 is the block diagram of the line voltage distribution pick-up unit using the voltage check device shown in Fig. 1.

Fig. 9 is the block diagram of the line voltage distribution pick-up unit using the voltage check device shown in Fig. 4.

Figure 10 is the block diagram of the floating circuit of the voltage check device being provided with the power supply unit different from the power supply unit in voltage check device shown in Fig. 1 or Fig. 4.

Figure 11 is the circuit diagram of the power supply unit in the portion of floating circuit shown in Figure 10.

Figure 12 is the floating circuit portion of the formation not using insulation division and the circuit diagram of differential amplifier circuit.

Figure 13 is the structural drawing of the voltage check device that the 3rd example of the present invention relates to.

Figure 14 is the structural drawing of the voltage check device that the 4th example of the present invention relates to.

Figure 15 is the structural drawing of the voltage check device that the 5th example of the present invention relates to.

Figure 16 is the structural drawing of the voltage check device that the 6th example of the present invention relates to.

Figure 17 is the structural drawing of the voltage check device that the 7th example of the present invention relates to.

Figure 18 is the frequency characteristic figure of the voltage signal S4 from the feedback control section output the voltage check device shown in Figure 17.

Figure 19 becomes the frequency characteristic figure extracting the reference signal Sr of the benchmark of signal in the signal extraction portion in the voltage check device shown in Figure 17.

Figure 20 is the frequency characteristic figure of the Insulation monitoring signal S2 exported from the floating circuit portion voltage check device shown in Figure 17.

Figure 21 is the frequency characteristic figure of the amplification detection signal S3 generated by the amplifying circuit in voltage check device shown in Figure 17.

Figure 22 is the frequency characteristic figure of the output signal So exported from the signal extraction portion voltage check device shown in Figure 17.

Embodiment

Below, be described with reference to the example of accompanying drawing to voltage check device and line voltage distribution pick-up unit.

[the first example]

First, with reference to accompanying drawing, the voltage check device 101 that the first example of the present invention relates to is described.

Voltage check device 101 is voltage check devices of non-contact type, as shown in Figure 1, be provided with floating (floating) circuit part 2 and main body circuit portion 3, and be configured to can detect for benchmark the alternating voltage V1 (detected object alternating voltage) resulted from detected object 4 with ground potential Vg non-contactly.

As shown in Figure 1, floating circuit portion 2 is provided with guard electrode 11, detecting electrode 12, power supply unit 13, test section 14 and insulation division 15.Guard electrode 11 uses conductive material (such as metal material), and form as the reference voltage portion in floating circuit portion 2, its inside contains detecting electrode 12, test section 14 and insulation division 15.In addition; as described later; because insulation division 15 has the signal inputted in its primary-side circuitry with the function exported from its secondary-side circuitry with the primary-side circuitry state that is electrical isolation; therefore should the position that covers of protected electrode 11 at least to primary-side circuitry, but also can adopt secondary-side circuitry also with the formation of guard electrode 11 covering.In addition, in this example as an example, guard electrode 11 is formed with peristome (hole) 11a.Detecting electrode 12 is formed as tabular as an example, and to be non-contacting state with guard electrode 11, is equipped on the position relative with peristome 11a in guard electrode 11.In addition, detecting electrode 12, when detecting alternating voltage V1, carries out capacitive coupling (being coupled by electrostatic capacitance C0) with detected object 4 as shown in Figure 1.

Power supply unit 13, as generation with the voltage Vr of guard electrode 11 for the floating power supply of the various floating voltages of benchmark (zero volt) and being formed.In addition, the floating voltage of generation supplies as work applied voltage each structural detail be disposed in guard electrode 11 by power supply unit 13.In this example as an example, power supply unit 13 possesses accumulator and DC/DC interchanger (all not shown) and forms, DC/DC interchanger is based on the DC voltage exported from accumulator by various floating voltage (when such as voltage Vr is zero volt, relative to the 1st floating voltage Vf+ that voltage Vr is positive voltage, and be the 2nd floating voltage Vf-of the negative voltage that its absolute value is equal with the 1st floating voltage Vf+ relative to voltage Vr.Below, also referred to as " floating voltage Vf+ ", " floating voltage Vf-") generate as work applied voltage.In addition; although not shown; but also can adopt replacement accumulator; and to guard electrode 11 in supply alternating voltage from the outside of guard electrode 11 with the state be electrically insulated by transformer, and by this alternating voltage be arranged in the rectification partes glabra in guard electrode 11 be transformed to DC voltage and to DC/DC interchanger supply formation.

Test section 14 is while being connected to detecting electrode 12, input contrast signal Ss (contrast signal Ss is added) from contrast signal efferent 31, and the detection signal S1 that changes exports according to the detected object electric current circulated based on alternating voltage V1 (the current signal composition produced by alternating voltage V1) Iv1 and two current values with reference to electric current (the current signal composition produced by contrast signal Ss) Is1 of circulating based on contrast signal Ss by amplitude.Specifically; test section 14 receives relative to the voltage Vr of guard electrode 11 to be the floating voltage Vf+ of positive voltage and to start for the supply of the floating voltage Vf-of negative voltage; and according to current signal I (detection electric current) generating amplitude according to the electric potential difference (V1-Vr) exchanged the detection signal S1 that changes exporting; wherein, current signal I circulates with the current value corresponding with the electric potential difference (V1-Vr) exchanged between alternating voltage V1 and the voltage Vr of guard electrode 11.In this situation, contrast signal Ss is exported (adding) to guard electrode 11 by from contrast signal efferent 31 described later.By this formation, voltage Vr is consistent with the voltage Vs of contrast signal Ss.Like this, above-mentioned current signal I by the reference electric current I s1 produced because of contrast signal Ss and because of alternating voltage V1 produce detected object electric current I v1 form, based on the detection signal S1 of this current signal I, also by based on reference to electric current I s1 voltage signal composition (hereinafter referred to as " reference voltage composition ") Vs1 and form based on voltage signal composition (hereinafter referred to as " detected object the voltage component ") Vv1 of detected object electric current I v1.In addition; test section 14 is owing to starting using the voltage of the guard electrode 11 of carrying out changing according to the voltage Vs of contrast signal Ss as benchmark and generating detection signal S1; therefore, it is anti-phase signal that the reference voltage composition Vs1 be contained in detection signal S1 becomes relative to the voltage Vs of contrast signal Ss.

In this example as an example, test section 14 as shown in Figure 2, comprises integrating circuit 21 and amplifying circuit 22 and is formed.Integrating circuit 21 is provided with: in-phase input end is connected to guard electrode 11 and inverting input is connected to the operational amplifier 21a of detecting electrode 12, the capacitor 21b between the inverting input being connected to operational amplifier 21a and output terminal and the resistance 21c in parallel with capacitor 21b.In this situation, capacitor 21b is as an example, and formed with the capacitor of 0.01 μ about F, resistance 21c is made up of the resistance of the such as high resistance of 1M about Ω.Therefore; in this integrating circuit 21; by main on capacitor 21b circulating current signal I; and while current-voltage conversion operation, carry out integration operation, the voltage signal S0 that the electric potential difference (V1-Vr) exchanged between the alternating voltage V1 of formation voltage value and the detected object 4 and voltage Vr of guard electrode 11 changes pro rata.In addition, in this integrating circuit 21, by means of only the words of capacitor 21b, the feedback quantity that there is near DC obviously declines and gain (gain) increases terrifically, the danger that operational amplifier 21a is saturated due to biased (offset) that cause because of bias current, in order to suppress the decline of the dynamic range caused because this is saturated, and be equipped with resistance 21c.Amplifying circuit 22, carries out voltage amplification by voltage signal S0 using the magnification of regulation and exports as detection signal S1.In addition, although not shown, also can by integrating circuit 21, be made up of the current-voltage conversion circuit such as current signal I being transformed to voltage signal and two circuit of integrating circuit that this voltage signal integration is exported as detection signal S1.

Insulation division 15, carries out electrical isolation and exports as Insulation monitoring signal S2 while input detection signal S1.Specifically, insulation division 15 is as an example, adopt optical insulation element (in the present example, photo-coupler is adopted as an example) and form, using being transfused to as the detection signal S1 in the light emitting diode (not shown) of its primary-side circuitry, export from the phototransistor as its secondary-side circuitry as Insulation monitoring signal S2.That is, insulation division 15 will be homophase with detection signal S1 and the amplitude of amplitude and detection signal S1 carries out the signal that changes pro rata, exports as Insulation monitoring signal S2.In addition, also can replace photo-coupler, and use primary-side circuitry to be made up of light emitting diode and secondary-side circuitry forms insulation division 15 by FET (field effect transistor) to the light MOS-FET (mos field effect transistor) formed.In this situation, in insulation division 15, its primary-side circuitry receives the supply of floating voltage Vf+, Vf-and action.In addition, when detection signal S1 is high-frequency interchange, transformer also can be used to form insulation division 15.

As shown in Figure 1, main body circuit portion 3 is provided with contrast signal efferent 31, signal extraction portion 32, handling part 33, storage part 34 and efferent 35.In this situation, contrast signal efferent 31 generates the fixing contrast signal Ss of the amplitude that changes with specified period for benchmark and voltage Vs with ground potential Vg (frequency and the fixing AC signal of amplitude.Sine wave signal is had as an example), and export to guard electrode 11.By like this, the voltage Vr of guard electrode 11 is defined as the voltage Vs of contrast signal Ss.That is, the voltage Vr of guard electrode 11 changes by the cycle specified with the state that the voltage Vs with contrast signal Ss is consistent.In this example; have employed the formation that contrast signal efferent 31 exports directly to guard electrode 11 with reference to signal Ss; but because contrast signal Ss is AC signal; although therefore not shown, also can be configured to contrast signal efferent 31 and be exported to guard electrode 11 with reference to signal Ss by capacitor.In addition, contrast signal efferent 31 also exports contrast signal Ss to signal extraction portion 32.In addition, the amplitude changing unit 36 be represented by dotted lines in same figure, is not contained in main body circuit portion 3 in this example.Therefore, the contrast signal Ss exported from contrast signal efferent 31 is directly transfused to signal extraction portion 32.In addition, in this example as an example, the frequency of contrast signal Ss is defined as the frequency higher than the frequency of the alternating voltage V1 of detected object 4.In this situation, can be also the frequency lower than the frequency of the alternating voltage V1 of detected object 4 with reference to the allocation of signal Ss.

Signal extraction portion 32 is as an example, be provided with amplifying circuit 41, adding circuit 42, synchro detection circuit 43 and control circuit 44, with the gain of regulation, Insulation monitoring signal S2 amplified and generate amplification detection signal S3, and with can adding or subtracting and calculate (in this example for adding) and offset like that by amplification detection signal S3 and contrast signal Ss by the signal content of the contrast signal Ss comprised in amplification detection signal S3 and contrast signal Ss, control gain when being amplified by Insulation monitoring signal S2, simultaneously, the signal content of alternating voltage V1 is extracted (generation) from amplification detection signal S3 and exports as output signal S0.In this situation; the signal content of the contrast signal Ss comprised in so-called amplification detection signal S3 is the signal content (what namely comprise in amplification detection signal S3 is the signal content of same frequency with contrast signal Ss) that the reference voltage composition Vs1 being contained in detection signal S1 because of the output to guard electrode 11 (adding) based on contrast signal Ss causes.

Specifically, amplifying circuit 41 is while isolated input detection signal S2, the magnification (gain can be more than 1 also can be less than 1) be prescribed with the level (DC voltage level) of control signal (the being specially control voltage) Sc by exporting from control circuit 44 amplifies Insulation monitoring signal S2, and generates and export amplification detection signal S3.As an example, as shown in Figure 3, amplifying circuit 41 is provided with operational amplifier 41a, the variable resistor element be disposed between the inverting input of operational amplifier 41a and ground potential (in the present example as an example, is J-FET (Junction Field Effect Transistor: junction field effect transistor.)) 41b and the resistance 41c that is disposed between the inverting input of operational amplifier 41a and output terminal and forming, its entirety is formed as in-phase amplification circuit.In this situation, the resistance value of variable resistor element 41b changes according to the level of the control signal Sc be transfused to.Therefore, Insulation monitoring signal S2 while making its magnification change at the level according to the control signal Sc be transfused to, amplifies using this magnification and exports as amplification detection signal S3 by amplifying circuit 41.In addition, as variable resistor element, resistance value carries out the element changed according to the voltage inputted from outside, also can use the element beyond J-FET or circuit and form.In this example as an example, variable resistor element 41b is configured to, and when the level of the control signal Sc be transfused to increases, its resistance value reduces, and when the level of control signal Sc reduces, its resistance value increases.By this formation, the magnification of amplifying circuit 41, increases when the level of control signal Sc increases, and reduces when the level of control signal Sc reduces.

Adding circuit 42; the voltage Vr that guard electrode 11 occurs is inputted (in this example as reference signal Sr; only by additional contrast signal Ss in guard electrode 11; therefore reference signal Sr is contrast signal Ss) while input amplification detection signal S3; two signals S3, Sr are added, and the signal that adds obtained by adding is exported as output signal So.In this situation as described above, detection signal S1 is by being anti-phase reference voltage composition Vs1 relative to contrast signal Ss and forming with the detected object voltage component Vv1 that alternating voltage V1 is homophase.Therefore, the Insulation monitoring signal S2 generated based on detection signal S1 and the amplification detection signal S3 being amplified by Insulation monitoring signal S2 and generate, also by being anti-phase signal content relative to contrast signal Ss and forming with the signal content that alternating voltage V1 is homophase.Therefore, adding circuit 42, by performing the addition process of two signals S3, Sr, and execution is that anti-phase signal content (hereinafter also referred to " inversion signal composition ") carries out the process of offsetting (elimination) with reference signal Sr (for contrast signal Ss in this example) by what form amplification detection signal S3 relative to contrast signal Ss.That is, adding circuit 42 plays a role as bucking circuit.In this situation, what comprise in output signal So is the signal content of same frequency with contrast signal Ss, is completely eliminated (being eliminated) is removed when the amplitude of inversion signal composition of formation amplification detection signal S3 is identical with the amplitude of reference signal Sr.On the other hand, be the signal content of same frequency with this contrast signal Ss, residue in when the amplitude of the inversion signal composition forming amplification detection signal S3 is different from the amplitude of reference signal Sr and output signal So, become anti-phase when the amplitude of the inversion signal composition forming amplification detection signal S3 is greater than the amplitude of reference signal Sr with contrast signal Ss, when the amplitude of the inversion signal composition of formation amplification detection signal S3 is below the amplitude of reference signal Sr and contrast signal Ss become homophase.

Synchro detection circuit 43, while being inputted by output signal So and contrast signal Ss, by output signal So being carried out synchronous detection with contrast signal Ss, and generates and exports rectified signal Vd.Specifically, synchro detection circuit 43 passes through synchronous detection, increase and decrease the absolute value of voltage is corresponding with the increase and decrease of the amplitude of the signal content (being specially with contrast signal Ss is the signal content of same frequency) of contrast signal Ss comprised in output signal So, and the phase place of the signal content of contrast signal Ss comprised in output signal So consistent with the phase place of contrast signal Ss time (same to phase time) and when departing from 180 ° (time anti-phase), generate the rectified signal Vd that also output polarity is different.In this example as an example, synchro detection circuit 43, generates and exports the signal content of regulation that comprises in output signal So and contrast signal Ss is the rectified signal Vd becoming positive polarity (positive voltage) with phase time, become negative polarity (negative voltage) when anti-phase.

Control circuit 44, generates the polarity according to the rectified signal Vd of input and increases and decreases the control signal Sc of voltage, and exporting to amplifying circuit 41.In this example as an example, control circuit 44, when the rectified signal Vd inputted is positive polarity, makes the level of control signal Sc increase, and on the other hand when the rectified signal Vd inputted is negative polarity, the level of control signal Sc is reduced.By above formation, in signal extraction portion 32, FEEDBACK CONTROL for the gain (magnification) of amplifying circuit 41 is undertaken by synchro detection circuit 43 and control circuit 44, control circuit 44 controls the magnification of amplifying circuit 41 according to rectified signal Vd, becomes fixing (being become same-amplitude with the amplitude of the contrast signal Ss being transfused to adding circuit 42 as reference signal Sr in this example) to make the amplitude of the inversion signal composition of formation amplification detection signal S3 (be the signal content of same frequency with contrast signal Ss).By like this, form the amplitude of the inversion signal composition of amplification detection signal S3, consistent with the amplitude of the reference signal Sr (being contrast signal Ss in this example) being transfused to adding circuit 42.Therefore, adding circuit 42 performs the addition process of amplification detection signal S3 and reference signal Sr, the inversion signal composition forming amplification detection signal S3 is offset (elimination) with contrast signal Ss, generate and output signal output So, wherein, output signal So to be made up of the voltage component (be the signal content of same frequency with alternating voltage V1) of the detected object electric current I v1 produced based on the alternating voltage V1 because of detected object 4.

In this situation, corresponding to the size of the electrostatic capacitance C0 formed between detected object 4 and detecting electrode 12, the reference electric current I s1 comprised in current signal I and detected object electric current I v1 changes with same ratio, and the reference voltage composition Vs1 comprised in detection signal S1 and detected object voltage component Vv1 also changes with same ratio.Therefore, about forming the inversion signal composition (be the signal content of same frequency with contrast signal Ss) of amplification detection signal S3 and being the signal content of same frequency with alternating voltage V1, two-component also changes with same ratio, but in signal extraction portion 32, by above-mentioned FEEDBACK CONTROL, amplification detection signal S3 is consistent with the amplitude of the amplitude and reference signal Sr (for contrast signal Ss in this example) that form the inversion signal composition (be the signal content of same frequency with contrast signal Ss) of this signal S3, is generated by amplifying circuit 41.Therefore, in the voltage check device 101 that this example is formed, based on the voltage component of the detected object electric current I v1 that output signal So comprises, with the size of electrostatic capacitance C0 independently its amplitude be all the size corresponding with the amplitude of alternating voltage V1 that produces on detected object 4, its amplitude becomes the state consistent with the amplitude of the alternating voltage V1 that detected object 4 produces in theory.

Handling part 33, be provided with A/D transducer and CPU (all not shown) and form, and performing: the voltage waveform (level) of output signal So being undertaken sampling by the sampling clock of assigned frequency and the stores processor being stored in storage part 34 after being transformed to numerical data D1, the voltage that calculates alternating voltage V1 according to this numerical data D1 output processing that calculates process and the alternating voltage V1 calculated is exported.Storage part 34 is made up of ROM (ROM (read-only memory)) or RAM (random access memory) etc., is previously stored with to calculate in process to be calculated by the voltage used at the voltage of handling part 33 to use chart TB.Calculate the production process with chart TB about this voltage, its summary is described.As an example; the contrast signal Ss of known voltage Vs (fixing) to be exported to guard electrode 11 and under the state of carrying out the FEEDBACK CONTROL utilizing synchro detection circuit 43 and control circuit 44; numerical data D1 is obtained while changing with the voltage step size (voltage step) of regulation by making the amplitude of the alternating voltage V1 that detected object 4 produces; contrast with the alternating voltage V1 changed in this voltage step size and the magnitude of voltage of numerical data D1 and alternating voltage V1 is together stored, thus making voltage and calculate and use chart TB.By this formation, handling part 33, calculates the magnitude of voltage obtaining the alternating voltage V1 corresponding with acquired numerical data D1 with chart TB by referring to voltage, thus can calculate the alternating voltage V1 of detected object 4.Efferent 35 in this example, is made up of display device as an example, in the output processing of handling part 33, and the waveform of display alternating voltage V1 or the voltage parameter that calculates etc. (amplitude or effective value).

Next, the detection operation of the alternating voltage V1 for detected object 4 utilizing voltage check device 101 to carry out is described.

First, relative with detected object 4 in non-contacting state with detecting electrode 12, floating circuit portion 2 (or voltage check device 101 is overall) is positioned near detected object 4.By like this, as shown in Figure 1, become the state forming electrostatic capacitance C0 between detecting electrode 12 and detected object 4.In this situation, the capacitance of electrostatic capacitance C0, with the distance of detecting electrode 12 and detected object 4 inversely proportional change, but once after being arranged in floating circuit portion 2, under the condition that the environment such as temperature are fixing, become fixing (not changing) value.In addition, due to electrostatic capacitance C0 capacitance generally minimum (such as count pF ~ tens of about pF), therefore, even if the frequency of alternating voltage V1 is hundreds of about Hz, the impedance between detected object 4 and detecting electrode 12 also can become very large value (number M Ω).Therefore; in this voltage check device 101; even if when the alternating voltage V1 of the detected object 4 and voltage Vr of guard electrode 11 differs widely (when electric potential difference Vdi is large); also the resistance to cheap products forced down of input can be used in the operational amplifier 21a forming test section 14; in this formation, the destruction of the operational amplifier 21a that electric potential difference Vdi also can be avoided to cause.

In addition; detecting electrode 12 is connected by AC deposition by electrostatic capacitance C0 with detected object 4, to form from ground potential Vg the current path A (in FIG with the path that dot-and-dash line represents) of the ground potential Vg that arrives through detected object 4, detecting electrode 12, test section 14, guard electrode 11 and contrast signal efferent 31.Therefore, in this current path A, the current signal I that the reference electric current I s1 that produced by the voltage Vs because of contrast signal Ss and the detected object electric current I v1 that produces because of the alternating voltage V1 of detected object 4 that circulates is formed.

By like this, in floating circuit portion 2, as shown in Figure 1, 2, the integrating circuit 21 integration current signal I of test section 14 and formation voltage signal S0, amplifying circuit 22 amplifies this voltage signal S0 and exports as detection signal S1.In addition, insulation division 15 inputs this detection signal S1, and exports as the Insulation monitoring signal S2 with detection signal S1 electrical isolation.

In addition, in the signal extraction portion 32 in main body circuit portion 3, as shown in Figure 1, amplifying circuit 41 is while isolated input detection signal S2, Insulation monitoring signal S2 amplifies by the magnification be prescribed with the voltage level of the control signal Sc by exporting from control circuit 44, and exports as amplification detection signal S3.Then, adding circuit 42, while input amplification detection signal S3 and reference signal Sr, after performing the addition process be added by two signal S3, Sr, exports as output signal So.In this situation, as described above, FEEDBACK CONTROL for the gain (magnification) of amplifying circuit 41 is undertaken by synchro detection circuit 43 and control circuit 44, and the amplitude forming the amplitude of the inversion signal composition (be the signal content of same frequency with contrast signal Ss) of the amplification detection signal S3 from amplifying circuit 41 and reference signal Sr (being contrast signal Ss in this example) is consistent.Therefore, by the addition process in adding circuit 42, the inversion signal composition forming amplification detection signal S3 is cancelled (elimination) by reference signal Sr, that is, the inversion signal composition forming amplification detection signal S3 is removed, and the output signal So be made up of the voltage component (be the signal content of same frequency with alternating voltage V1) of the detected object electric current I v1 produced based on the alternating voltage V1 because of detected object 4 is output.

Next, handling part 33 performs stores processor, is transformed to numerical data D1 and is stored in storage part 34 while being inputted by output signal So.Then, handling part 33 performs voltage and calculates process.Calculate in process at this voltage, handling part 33 is while reading the numerical data D1 stored in storage part 34, and reference voltage calculates and obtains the alternating voltage V1 corresponding with the numerical data D1 read with chart TB.In addition, the alternating voltage V1 that handling part 33 obtains according to this, calculates the effective value or amplitude etc. of such as alternating voltage V1 and is stored in storage part 34.Finally, handling part 33 performs output processing, by the effective value of the alternating voltage V1 of storage in storage part 34 or amplitude etc., is shown in the efferent 35 be made up of display device.By like this, the detection of the alternating voltage V1 to detected object 4 of voltage check device 101 is utilized to complete.In addition, in output processing, handling part 33 also can be adopted according to the alternating voltage V1 obtained, the voltage waveform of alternating voltage V1 to be shown in the formation of efferent 35.

In example described above, contrast signal efferent 31 exports contrast signal Ss to guard electrode 11, receive floating voltage Vf+, the supply of Vf-and the test section 14 started, according to passing through detecting electrode 12 between detected object 4 and guard electrode 11, I is believed with the electric current that the current value that the electric potential difference (V1-Vr) with the interchange between alternating voltage V1 and the voltage Vr of guard electrode 11 is corresponding circulates, export the detection signal S1 that amplitude carries out according to the electric potential difference (V1-Vr) exchanged changing, insulation division 15 inputs detection signal S1 and exports as Insulation monitoring signal S2, signal extraction portion 32 with make to comprise in Insulation monitoring signal S2 with the contrast signal Ss amplitude that is identical signal content become be prescribed in advance amplitude (can by with contrast signal Ss add or subtract calculate that to offset what comprise in amplification detection signal S3 be the amplitude of identical signal content with contrast signal Ss) like that, that is become like that fixing, the amplitude of Insulation monitoring signal S2 is controlled and exports as amplification detection signal S3, simultaneously, by amplitude by adding or subtracting calculation between the amplification detection signal S3 that so controls and the contrast signal Ss exported from contrast signal efferent 31, and remove in amplification detection signal S3 the signal content identical with contrast signal Ss comprised, and export as output signal So, handling part 33 calculates alternating voltage V1 according to the level of output signal So, wherein, output signal So is made up of the voltage component occurred based on detected object electric current I v1 (current component that the alternating voltage V1 because of detected object 4 causes and occurs).

Therefore, adopt the words of this example, signal extraction portion 32 controls the amplitude of amplification detection signal S3, become fixing with the amplitude of the signal content that to make with contrast signal Ss be same frequency, by utilizing adding or subtract and calculating and remove in amplification detection signal S3 the signal content identical with contrast signal Ss that comprise and export as outputing signal So of this amplification detection signal S3 and contrast signal Ss, even if the coupling capacitance (electrostatic capacitance C0) between detected object 4 and detecting electrode 12 is unknown (no matter value of electrostatic capacitance C0), owing to being controlled as in fixing sensitivity for the sensitivity of alternating voltage V1, that is, amplitude due to the voltage component based on the detected object electric current I v1 comprised in output signal So is controlled as in the size corresponding with the amplitude of alternating voltage V1, therefore, by detecting this voltage component comprised in output signal So, calculating of electrostatic capacitance C0 can not be carried out, and detect alternating voltage V1 non-contactly.

In addition, in this example, in signal extraction portion 32, synchro detection circuit 43 is by employing the synchronous detection of contrast signal Ss, detect the rectified signal Vd represented the amplitude of the signal content of the contrast signal Ss about comprising in amplification detection signal S3 or output signal So, control circuit 44 controls the gain of amplifying circuit 41 according to this rectified signal Vd.Therefore, adopt this voltage check device 101, the signal content of contrast signal Ss correctly can be detected by synchronous detection, consequently, due to the signal content of the contrast signal Ss comprised in amplification detection signal S3 can be offset accurately, the signal content of the contrast signal Ss comprised in output signal So can be reduced thus significantly, therefore, it is possible to improve the accuracy of detection of alternating voltage V1 further.

In addition, in this example, adding circuit 42 forms as bucking circuit by signal extraction portion 32, wherein, it is anti-phase signal content (inversion signal composition) carries out offsetting (elimination) process with reference signal Sr (for contrast signal Ss in this example) relative to contrast signal Ss that adding circuit 42 performs what form amplification detection signal S3, control circuit 44 controls the gain of amplifying circuit 41, make to be transfused to the inversion signal composition (signal content of contrast signal Ss) comprised in the amplification detection signal S3 of adding circuit 42 to be offset by reference signal Sr.Therefore, adopt this voltage check device 101, bucking circuit can be formed by the so simple circuit of circuit with additive, therefore, it is possible to while seeking the simplification that device forms positively generating output signal So.

In addition, adopt the words of this example, by being provided with the handling part 33 detecting alternating voltage V1 according to output signal So, and alternating voltage V1 can being detected at certain intervals, maybe the alternating voltage V1 detected is stored and be stored in storage part 34 or the alternating voltage V1 that stores according to the storage part 34 and voltage waveform of alternating voltage V1 is shown in efferent 35 for handling part 33.

In addition, adopt this example, because handling part 33 calculates alternating voltage V1 according to output signal So, therefore, it is possible to detect (measurement) alternating voltage V1.

In addition, in above-mentioned example, the signal content of the contrast signal Ss comprised in amplification detection signal S3 is utilized to be anti-phase feature relative to reference signal Sr (being contrast signal Ss in this example), use adding circuit 42 that the signal content of the contrast signal Ss comprised in amplification detection signal S3 and contrast signal Ss are offset as bucking circuit, but at test section 14, in insulation division 15 and amplifying circuit 41, also detection signal S1 can be made, the reverse-phase of Insulation monitoring signal S2 and amplification detection signal S3, or make reference signal Sr anti-phase and bucking circuit is exported.In this formation, because the signal content and contrast signal Ss that also can make the contrast signal Ss comprised in amplification detection signal S3 are formed as homophase, therefore, in this case by using subtraction circuit as bucking circuit, and the signal content of the contrast signal Ss comprised in amplification detection signal S3 and contrast signal Ss can be offset.

In addition, in above-mentioned example, have employed the formation inputted directly to bucking circuit (being adding circuit 42 in above-mentioned example) with reference to signal Ss as reference signal Sr, but as shown in phantom in Figure 1, also can adopt and arrange amplitude changing unit 36 between contrast signal efferent 31 and adding circuit 42, using the formation being changed to k by the amplitude of contrast signal Ss exported from contrast signal efferent 31 doubly export as reference signal Sr1 to adding circuit 42 after (k is arithmetic number) in amplitude changing unit 36.This amplitude changing unit 36 can be made up of simply the attenuator such as consisted of divider resistance etc. (attenuator).In addition, also can by amplitude changing unit 36 by the amplifier that signal amplifies being formed with the gain of regulation (k is doubly), the amplitude of comparison voltage signal Sr and the amplitude of reference signal Sr1 is increased.In these are formed, in signal extraction portion 32, the amplitude of the signal content of the contrast signal Ss comprised about amplification detection signal S3, with k doubly after the amplitude (amplitude of reference signal Sr1) of contrast signal Ss become consistent such and be fed control.In this situation, the signal content of the contrast signal Ss comprised in amplification detection signal S3 with by k doubly after the state that is cancelled in adding circuit 42 of reference signal Sr1 under, based on the amplitude of the voltage component of the detected object electric current I v1 caused because of the alternating voltage V1 that comprises in output signal So, also with by k doubly after state be detected.Therefore, it is possible to by the voltage component based on this detected detected object electric current I v1 is formed as 1/k doubly, and detect alternating voltage V1.

Therefore, adopting this formation, by changing the multiplying power k in amplitude changing unit 36, the scope that can detect (measurement) alternating voltage V1 can be expanded.Such as, the incoming level of the output signal So in handling part 33 has regulation (to be provided with in the formation of A/D transducer like that above-mentioned, the incoming level of output signal So is limited according to the specified input of A/D transducer) when, by multiplying power k is set to numerical value 1/10, compared with when being set to numerical value 1 (formation as reference signal Sr inputs directly to adding circuit 42 with reference to signal Ss), also while the incoming level of the output signal So of satisfied regulation, (measurement) more high-tension alternating voltage V1 can be detected.

In addition, in above-mentioned example, have employed by by detecting electrode 12, power supply unit 13, test section 14 and insulation division 15 are contained in guard electrode 11, and form floating circuit portion 2 from main body circuit portion 3 in different body component, while raising CMRR (Common Mode Rejection Ratio), the formation of the detection of the alternating voltage V1 of high pressure can be carried out, but, when without the need to making test section 14 dynamic with quick condition (such as, alternating voltage V1 is comparatively low pressure, or be not required the situation of high CMRR), also can adopt and not use guard electrode 11, the formation of power supply unit 13 and insulation division 15.For such example, be below described.

[the second example]

The voltage check device 102 that second example of the present invention relates to as shown in Figure 4, replaces the floating circuit portion 2 of voltage check device 101, and is provided with detecting electrode 12 and test section 14A.Therefore, voltage check device 102 is provided with detecting electrode 12, test section 14A and main body circuit portion 3, and is configured to detect the alternating voltage V1 resulted from detected object 4 non-contactly.In addition, about detecting electrode 12 and main body circuit portion 3, form due to identical with voltage check device 101, therefore give identical symbol and the repetitive description thereof will be omitted, mainly the test section 14A different from voltage check device 101 is described.

Test section 14A, with each structural detail (contrast signal efferent 31, signal extraction portion 32 and handling part 33 etc.) forming main body circuit portion 3 in the same manner never illustrated power supply receive the supply of work applied voltage (with ground potential Vg for benchmark and the positive voltage Vcc+ that generates and negative voltage Vcc-) and action.In addition, test section 14A as shown in Figure 4, contrast signal Ss (contrast signal Ss is added) is inputted while being connected to detecting electrode 12, and detect by resulting from the input of the existence of alternating voltage V1 and the detected object electric current I v1 that circulates between detecting electrode 12 and detected object 4 and the voltage Vs that results from contrast signal Ss and current signal I (=Iv1+Is1) that the reference electric current I s1 that circulates between detecting electrode 12 and detected object 4 is formed, meanwhile, the detection signal S1 that amplitude carries out according to the current value of current signal I changing is exported.In addition, this current signal I be alternatively correspond to that the electric potential difference (V1-Vr) exchanged between alternating voltage V1 and the voltage Vr (=voltage Vs) of guard electrode 11 and its amplitude carry out changing, namely with the current signal carrying out circulating corresponding to the current value of this electric potential difference (V1-Vr).

Test section 14A, such as shown in Fig. 5 as one, is provided with and detects resistance 61 and differential amplify portion 62 in this example.Detect resistance 61, while at one end side is connected to detecting electrode 12, another side is connected on contrast signal efferent 31.Differential amplify portion 62 is made up of the known instrument amplifier being provided with three operational amplifier A P1 ~ AP3 and 7 resistance R1 ~ R7.In addition, in this differential amplify portion 62, each resistance R6, R7 are connected in parallel to capacitor C1, C2 respectively, the output stage (output stage) comprising operational amplifier A P3 has integrating function and forms.In addition, in this differential amplify portion 62, balance is kept (that is between resistance on the position being in symmetry in each resistance R1 ~ R7, R2 and R3, R4 and R5 and R6 and R7, be defined as identical resistance value respectively), and capacitor C1, C2 are also kept to balance (C1, C2 are defined as identical capacitance).In addition, in differential amplify portion 62, the in-phase input end of the operational amplifier A P1 played a role as the input end of in differential amplify portion 62 is connected on one end of detection resistance 61, and the in-phase input end of the operational amplifier A P2 played a role as another input end in differential amplify portion 62 is connected on contrast signal efferent 31.In this differential amplify portion 62, when the voltage being input into each input end is set to Vin1, Vin2, detection signal S1 represents with following formula.

S1＝(Vin2-Vin1)×(1+2×R2/R1)×R6/R4

In this situation, (Vin2-Vin1) in the formula of above-mentioned S1, represents the voltage being betided the two ends detecting resistance 61 by the circulation of current signal I (=Iv1+Is1).Therefore, test section 14A as described above, exports amplitude corresponding with the current value of current signal I (=Iv1+Is1) and carry out the detection signal S1 that changes.

In main body circuit portion 3, detection signal S1 amplifies with the gain of regulation and generates amplification detection signal S3 by signal extraction portion 32, and with can adding or subtracting and calculate and offset like that by amplification detection signal S3 and contrast signal Ss by the signal content of the contrast signal Ss comprised in amplification detection signal S3, control gain when detection signal S1 amplifies, meanwhile, the signal content of alternating voltage V1 extracted (generation) from amplification detection signal S3 and export as output signal So.In this situation, the signal content of the contrast signal Ss comprised in so-called amplification detection signal S3, refer to the reference voltage composition Vs1 (what namely, comprise in amplification detection signal S3 is the signal content of same frequency with contrast signal Ss) comprised in detection signal S1.

Then, in the same manner as the voltage check device 101 that handling part 33 and the first example relate to, calculate process and output processing by performing stores processor, voltage, and calculate the effective value of alternating voltage V1 or amplitude etc., and be shown in the efferent 35 be made up of display device.By like this, the detection of the alternating voltage V1 to detected object 4 of voltage check device 102 is utilized to terminate.

Therefore, in the voltage check device 102 that this example relates to, also in the same manner as the voltage check device 101 related to the first example, what control that the amplitude and making of amplification detection signal S3 comprises in amplification detection signal S3 by signal extraction portion 32 is the signal content of same frequency with contrast signal Ss amplitude is fixing, and utilize adding or subtract and calculating and remove and that comprise in amplification detection signal S3 to export with signal content that is contrast signal Ss same frequency and as outputing signal So of this amplification detection signal S3 and contrast signal Ss, even if thus the coupling capacitance (electrostatic capacitance C0) between detected object 4 and detecting electrode 12 is unknown (no matter value of electrostatic capacitance C0), owing to being controlled as in fixing sensitivity for the sensitivity of alternating voltage V1, that is because the amplitude of the voltage component based on the detected object electric current I v1 comprised in output signal So is controlled as in the size corresponding with the amplitude of alternating voltage V1, therefore, by detecting this voltage component comprised in output signal So, do not carry out calculating of electrostatic capacitance C0, also alternating voltage V1 can be detected non-contactly.

In addition, in the voltage check device 102 that this example relates to, also in the same manner as the voltage check device 101 related to the first example, in signal extraction portion 32, synchro detection circuit 43 detects by employing the synchronous detection of contrast signal Ss the rectified signal Vd represented the amplitude of the signal content of the relevant contrast signal Ss comprised in amplification detection signal S3 or output signal So, and control circuit 44 controls the gain of amplifying circuit 41 according to this rectified signal Vd.Therefore, adopt the words of this example, the signal content of contrast signal Ss correctly can be detected by synchronous detection, consequently, the signal content of the contrast signal Ss comprised in amplification detection signal S3 can be offset accurately, and the signal content of the contrast signal Ss comprised in output signal So can be reduced thus significantly, therefore, it is possible to improve the accuracy of detection of alternating voltage V1 further.

In addition, in the voltage check device 102 that this example relates to, adding circuit 42 also forms as bucking circuit by signal extraction portion 32, wherein, it is anti-phase signal content (inversion signal composition) to offset (elimination) process with reference signal Sr (for contrast signal Ss in this example) relative to contrast signal Ss that adding circuit 42 performs what form amplification detection signal S3, control circuit 44 controls the gain of amplifying circuit 41, make to be transfused to the inversion signal composition (signal content of contrast signal Ss) comprised in the amplification detection signal S3 in adding circuit 42 to be offset by reference signal Sr.Therefore, adopt this example, also can form bucking circuit by the so simple circuit of circuit with additive, therefore, it is possible to while the simplification seeking device formation, positively generating output signal So.

In addition, in above-mentioned voltage check device 102, also be utilize the signal content of the contrast signal Ss comprised in amplification detection signal S3 to be anti-phase feature relative to reference signal Sr (being contrast signal Ss in this example), and use adding circuit 42 as bucking circuit, the signal content of the contrast signal Ss comprised in amplification detection signal S3 and contrast signal Ss are offset, but, in test section 14A or amplifying circuit 41, also can make the reverse-phase of detection signal S1 or amplification detection signal S3, or make reference signal Sr anti-phase and bucking circuit is exported.In this formation, be homophase due to the signal content of the contrast signal Ss comprised in amplification detection signal S3 and contrast signal Ss also can be made, therefore, adopt the words of this formation, by subtraction circuit is used as bucking circuit, the signal content of the contrast signal Ss comprised in amplification detection signal S3 and contrast signal Ss can be offset.

In addition, in the above example, have employed the formation inputted directly to bucking circuit (being adding circuit 42 in above-mentioned example) with reference to signal Ss as reference signal Sr, but as shown in phantom in Figure 4, also can adopt and arrange amplitude changing unit 36 between contrast signal efferent 31 and adding circuit 42, the formation exported to adding circuit 42 as reference signal Sr1 after making the amplitude of the contrast signal Ss exported from contrast signal efferent 31 change to k times (k is arithmetic number) amplitude changing unit 36.Adopting this formation, identically with voltage check device 101, by changing the multiplying power k in amplitude changing unit 36, and the scope of the alternating voltage V1 that can detect (measurement) can be expanded.

In addition, in the voltage check device 101 that the first example relates to, have employed such as between insulation division 15 and amplifying circuit 41, between contrast signal efferent 31 and adding circuit 42, and the formation be directly connected respectively between contrast signal efferent 31 with synchro detection circuit 43, in addition, in the voltage check device 102 that the second example relates to, have employed such as between test section 14A and amplifying circuit 41, between contrast signal efferent 31 and adding circuit 42, and the formation be directly connected respectively between contrast signal efferent 31 with synchro detection circuit 43, although not shown, but also can adopt and make the intervenient formation of impact damper as required.In addition, for have employed, the contrast signal Ss exported from contrast signal efferent 31 is illustrated with the example of intact level to the formation that synchro detection circuit 43 supplies above, although not shown, but as an example also can adopt and use the attenuator that is made up of divider resistance etc. and be reduced to the level of needs and forming that synchro detection circuit 43 is supplied with reference to signal Ss.

In addition, although not shown, but also can adopt following formation, that is: by arrange in main body circuit portion 3 using be transformed to as the Insulation monitoring signal S2 of simulating signal numerical data A/D transformation component and using as the A/D transformation component being transformed to numerical data by the contrast signal Ss of the simulating signal that supplies signal extraction portion 32 from contrast signal efferent 31, and carry out all or part of formation of the process in signal extraction portion 32 with digital processing.In this situation, also can adopt the formation making handling part 33 have the function in signal extraction portion 32, adopt this formation, the number of packages of circuit block can be reduced significantly.In addition, both software can have been utilized to the function of the function and signal extraction portion 32 that realize handling part 33, hardware (DSP (Digital Signal Processor, digital signal processor) or logic array (Logic Array)) also can be utilized to realize.

In addition, above the example that the AC signal (as a such as sine wave signal) that frequency and amplitude are fixed exports as contrast signal Ss is illustrated by contrast signal efferent 31, but, also contrast signal efferent 31A as shown in Figure 6 can be adopted such, replace sine wave signal and the formation that exported as contrast signal Ss by square-wave signal.Specifically, contrast signal efferent 31A, is provided with the square wave generative circuit 31a generating square wave (square-wave signal) and the integrating circuit 31b exported using square wave (square-wave signal) integration and as integration square wave (integration square-wave signal).This contrast signal efferent 31A, the synchro detection circuit 43 of square-wave signal as contrast signal Ss to signal extraction portion 32 generated by square wave generative circuit 31a is exported, meanwhile, the adding circuit 42 of this square-wave signal as reference signal Sr to signal extraction portion 32 is exported.In addition, contrast signal efferent 31A, exports the integration square-wave signal exported from integrating circuit 31b test section 14 (being test section 14A in voltage check device 102) as contrast signal Ss.In this situation, because test section 14 (14A) is connected in series with electrostatic capacitance C0 by detecting electrode 12, therefore, the reference electric current I s1 circulated in the circuit comprising this test section 14 (14A) and electrostatic capacitance C0, becomes the signal after with reference to signal Ss differential.

Therefore, by the contrast signal Ss integration utilizing integrating circuit 31b will export from contrast signal efferent 31A to test section 14 (14A) in advance, and form square wave generative circuit 31a simply by using logical circuit (logic circuit) etc., the formation of contrast signal efferent 31A entirety can be made to become simple, simultaneously, by the reference electric current I s1 circulated in the circuit comprising test section 14 (14A) and electrostatic capacitance C0, be formed as the square-wave signal identical with the square-wave signal exported to signal extraction portion 32 from contrast signal efferent 31A.By like this, device can be made to form (being specially the formation of contrast signal efferent 31A entirety) and to become simple, simultaneously, in signal extraction portion 32, adding circuit 42 can utilize reference signal Sr (being contrast signal Ss in this example) and positively the inversion signal composition relative to contrast signal Ss forming amplification detection signal S3 be offset (elimination), thus can positively extract the signal content of alternating voltage V1 from amplification detection signal S3 and export as output signal So, simultaneously, synchro detection circuit 43 can utilize contrast signal Ss and positively carry out synchronous detection to output signal So.

In addition, contrast signal efferent 31B as shown in Figure 7 also can be adopted such, be provided with pseudo noise generative circuit 31c and form, and using formation that pseudo noise signal exports as contrast signal Ss.In this situation, contrast signal efferent 31B, the synchro detection circuit 43 of the pseudo noise signal generated by pseudo noise generative circuit 31c as contrast signal Ss to test section 14 (14A) and signal extraction portion 32 is exported, meanwhile, the adding circuit 42 of this pseudo noise signal as reference signal Sr to signal extraction portion 32 is exported.In addition, pseudo noise generative circuit 31c, can use the known various shift register of the linear feedback shift register (Linear Feedback Shift Register) of M series etc. etc. as an example and form, or use generates the microcomputer of pseudo noise signal by software process and forms.By using the contrast signal efferent 31B formed like this, the voltage check device 101 (101A) of the impact of can realize being difficult to being interfered (noise).

[configuration example of line voltage distribution pick-up unit]

Next, the line voltage distribution pick-up unit 51 of the voltage check device 101 utilizing multiple first example to relate to is described.

First, be described with reference to the formation of accompanying drawing to line voltage distribution pick-up unit 51.In addition, below the example of the line voltage distribution of alternating circuit (hereinafter also referred to as " circuit ") R, S, T of detection three-phase (R phase, S-phase and T-phase) three-wire system is described.

Line voltage distribution pick-up unit 51, as one such as shown in Fig. 8, be provided with the voltage check device 101 of the number of circuit R, S, T (three) (following, with each circuit R, S, T-phase is corresponding and be called that voltage check device 101r, 101s, 101t are (following, also referred to as " voltage check device 101 " when not distinguishing especially)), calculating section 52 and display part 53, and be configured to detect the line voltage distribution Vrs between circuit R, S, the line voltage distribution Vst between circuit S, T and the line voltage distribution Vrt between circuit R, T non-contactly.

As shown in Figure 8, each voltage check device 101 is respectively equipped with above-mentioned floating circuit portion 2 and main body circuit portion 3 and forms in the same manner, each circuit R, S, T are detected the effective value of alternating voltage Vrp, Vsp, Vtp (being respectively detected object alternating voltage) of these circuit as detected object, and will represent that the data of effective value are as detection data Dva, Dvb, Dvc and export.Below, for detection data Dva, Dvb, Dvc, when not distinguishing especially also referred to as " detecting data Dv ".In this example, the efferent 35 of each voltage check device 101, is made up of the dispensing device that can carry out the transmission of data, has the function detection data Dva inputted from handling part 33, Dvb, Dvc being sent to calculating section 52.In addition, for other the structural detail except efferent 35 in voltage check device 101, due to identical with above-mentioned formation, therefore detailed description is omitted.

Calculating section 52, is provided with CPU and storer (all not shown) and forms, and performs the line voltage distribution calculating (detecting) line voltage distribution according to the detection data Dv exported from each voltage check device 101 and calculate process.In addition, what line voltage distribution was calculated process by calculating section 52 the results are shown in display part 53.Display part 53, is made up of the monitoring device of liquid crystal display etc. in this example.In addition, also can be made up of the printing equipment of printer etc.In addition, each main body circuit portion 3 is as following, and mutual position (such as the basket in the main body circuit portion 3) G1 becoming ground potential Vg is connected each other.In addition, as an example, calculating section 52 and display part 53, the supply of power circuit (not shown) receiver voltage comprised from any one the main body circuit portion 3 three main body circuit portions 3 and carry out work.

Next, the detection action of line voltage distribution pick-up unit 51 is described.

First, as shown in Figure 8, when detecting, in order to the alternating voltage Vrp utilizing voltage check device 101r to detect circuit R, and making its floating circuit portion 2 near circuit R, meanwhile, making its detecting electrode 12 relative with corresponding circuit R.Similarly, for other voltage check device 101s, 101t, in order to detect alternating voltage Vsp, Vtp of circuit S, T, also make the detecting electrode 12 in each floating circuit portion 2 respectively with corresponding circuit S, T-phase pair.By like this, become in each detecting electrode 12 and each state being formed with electrostatic capacitance C0 (with reference to Fig. 1) between circuit R, S, T respectively, in each voltage check device 101r, 101s, 101t, the detection of alternating voltage Vrp, Vsp, Vtp of corresponding circuit R, S, T is started.In this situation as described above, in each voltage check device 101r, 101s, 101t, regardless of the capacitance of electrostatic capacitance C0, all can correctly detect alternating voltage Vrp, Vsp, Vtp by handling part 33.

In addition, in each voltage check device 101r, 101s, 101t, the effective value of alternating voltage Vrp, Vsp, Vtp of each circuit R, S, T that efferent 35 will be calculated by handling part 33, respectively as detection data Dva, Dvb, Dvc and export.

Calculating section 52, inputs each detection data Dva exported from each voltage check device 101, Dvb, Dvc and is stored in storer.Then, calculating section 52 performs line voltage distribution and calculates process.Specifically, calculating section 52, by calculating the differential voltage of each effective value of alternating voltage Vrp, Vsp represented by each detection data Dva, Dvb, and obtains (detecting) each line voltage distribution Vrs between circuit R, S.In addition, calculating section 52 similarly, by calculating the differential voltage of each effective value of alternating voltage Vsp, Vtp represented by each detection data Dvb, Dvc, and obtain (detecting) each line voltage distribution Vst between circuit S, T, by calculating the differential voltage of each effective value of alternating voltage Vrp, Vtp represented by each detection data Dva, Dvc, and obtain (detecting) each line voltage distribution Vrt between circuit R, T.In addition, calculating section 52 makes line voltage distribution Vrs, Vst, the Vrt calculated be shown in display part 53.

Like this, adopt the words of this line voltage distribution pick-up unit 51, by using voltage check device 101, even if the detecting electrode 12 in each voltage check device 101 and each coupling capacitance (electrostatic capacitance C0) between circuit R, S, T as the detected object of each voltage check device 101 are under unknown state, also these coupling capacitances be can calculate, and line voltage distribution Vrs, Vst, Vrt correctly detected non-contactly.

[other configuration examples of line voltage distribution pick-up unit]

Next, to utilizing the line voltage distribution pick-up unit 51A of multiple above-mentioned voltage check device 102 to be described.

First, be described with reference to the formation of accompanying drawing to line voltage distribution pick-up unit 51A.In addition, for the formation identical with line voltage distribution pick-up unit 51, also the repetitive description thereof will be omitted to give identical symbol.In addition, below the example of the line voltage distribution of circuit R, S, T of detection three-phase three-wire system is described.

Line voltage distribution pick-up unit 51A, as one such as shown in Fig. 9, be provided with the voltage check device 102 of the number of circuit R, S, T (three) (following, with each circuit R, S, T-phase is corresponding and be called that voltage check device 102r, 102s, 102t are (following, also referred to as " voltage check device 102 " when not distinguishing especially)), calculating section 52 and display part 53, and be configured to detect the line voltage distribution Vrs between circuit R, S, the line voltage distribution Vst between circuit S, T and the line voltage distribution Vrt between circuit R, T non-contactly.

Each voltage check device 102, as shown in Figure 9, be respectively equipped with above-mentioned detecting electrode 12, test section 14A and main body circuit portion 3 and form in the same manner, each circuit R, S, T are detected the effective value of alternating voltage Vrp, Vsp, Vtp (being respectively detected object alternating voltage) of these circuit as detected object, and will represent that the data of effective value are as detection data Dva, Dvb, Dvc and export.In this example, the efferent 35 of each voltage check device 102, is made up of the dispensing device that can carry out the transmission of data, has the function detection data Dva inputted from handling part 33, Dvb, Dvc being sent to calculating section 52.In addition, for other structural details except efferent 35 in voltage check device 102, due to identical with above-mentioned formation, therefore detailed description is omitted.In addition, for calculating section 52 and display part 53, due to identical with above-mentioned line voltage distribution pick-up unit 51, therefore also omit detailed description.

Next, the detection action of line voltage distribution pick-up unit 51A is described.

First, as shown in Figure 9, when detecting, in order to the alternating voltage Vrp utilizing voltage check device 102r to detect circuit R, and make its detecting electrode 12 near circuit R also relatively.Similarly, for other voltage check device 102s, 102t, in order to detect alternating voltage Vsp, Vtp of circuit S, T, also make each detecting electrode 12 respectively with corresponding circuit S, T-phase pair.By like this, become in each detecting electrode 12 and each state being formed with electrostatic capacitance C0 (with reference to Fig. 4) between circuit R, S, T respectively, in each voltage check device 102r, 102s, 102t, the detection of alternating voltage Vrp, Vsp, Vtp of corresponding circuit R, S, T is started.In this situation as described above, in each voltage check device 102r, 102s, 102t, regardless of the capacitance of electrostatic capacitance C0, all can correctly detect alternating voltage Vrp, Vsp, Vtp by handling part 33.

In addition, in each voltage check device 102r, 102s, 102t, the effective value of alternating voltage Vrp, Vsp, Vtp of each circuit R, S, T that efferent 35 will be calculated by handling part 33, respectively as detection data Dva, Dvb, Dvc and export.

Calculating section 52, inputs each detection data Dva exported from each voltage check device 102, Dvb, Dvc and is stored in storer.Then, calculating section 52 performs line voltage distribution and calculates process, by calculating each detection data Dva, alternating voltage Vrp represented by Dvb, the differential voltage of each effective value of Vsp, and obtain each circuit R, line voltage distribution Vrs between S, in addition, by calculating each detection data Dvb, alternating voltage Vsp represented by Dvc, the differential voltage of each effective value of Vtp, and obtain each circuit S, line voltage distribution Vst between T, in addition, by calculating each detection data Dva, alternating voltage Vrp represented by Dvc, the differential voltage of each effective value of Vtp, and obtain each circuit R, line voltage distribution Vrt between T.In addition, calculating section 52 makes line voltage distribution Vrs, Vst, the Vrt calculated be shown in display part 53.

Like this, adopt the words of this line voltage distribution pick-up unit 51A, by using voltage check device 102, even if the detecting electrode 12 in each voltage check device 102 and each coupling capacitance (electrostatic capacitance C0) between circuit R, S, T as the detected object of each voltage check device 102 are under unknown state, also these coupling capacitance be can calculate, and line voltage distribution Vrs, Vst, Vrt correctly detected non-contactly.

[variation]

In addition, above to the floating voltage Vf+ used in the voltage check device 101 related to as generation first example, the power supply unit 13 of Vf-, and be provided with the formation of accumulator and DC/DC interchanger (all not shown), and replace accumulator and by transformer with the state of electrical isolation from guard electrode 11 externally to supply alternating voltage in guard electrode 11, and the formation utilizing the rectification partes glabra be arranged in guard electrode 11 that this alternating voltage is transformed to DC voltage and supply DC/DC interchanger is illustrated, but, as shown in Figure 10, also the formation using power supply unit 13A can be adopted, wherein, power supply unit 13A forms each structural detail (contrast signal efferent 31 in main body circuit portion 3 according to never illustrated power supply supply, signal extraction portion 32 and handling part 33 etc.) work applied voltage (the positive voltage Vcc+ generated for benchmark with ground potential Vg and negative voltage Vcc-), generate the voltage Vr of guard electrode 11, namely with the above-mentioned floating voltage Vf+ that the voltage Vs of contrast signal Ss is benchmark (zero volt), Vf-.

As shown in figure 11, this power supply unit 13A is provided with the first series-connection power supplies circuit 61 and the second series-connection power supplies circuit 62, wherein, first series-connection power supplies circuit 61, when the voltage Vr of guard electrode 11 is zero volt, generating relative to the voltage Vr of guard electrode 11 according to positive voltage Vcc+ is the floating voltage Vf+ of fixing positive voltage, second series-connection power supplies circuit 62, generating relative to the voltage Vr of guard electrode 11 according to negative voltage Vcc-is the floating voltage Vf-(equaling the voltage of the absolute value of the difference of floating voltage Vf+ and voltage Vr with the absolute value of the difference of voltage Vr) that its absolute value equals the negative voltage of floating voltage Vf+.Specifically, first series-connection power supplies circuit 61, be provided with bipolar npn transistor npn npn 61a (hereinafter also referred to as " the first transistor 61a "), the first resistance 61b, the first voltage stabilizing diode 61c (voltage of voltage regulation Vz) and the first capacitor 61d.In this situation, the collector terminal of the first transistor 61a is connected to the supply lines of positive voltage Vcc+, and emitter terminal is connected to the outlet line of floating voltage Vf+, and base terminal is connected to the cathode terminal of the first voltage stabilizing diode 61c.In addition, the anode terminal of the first voltage stabilizing diode 61c is connected to the supply lines of voltage Vr.One end of first resistance 61b is connected to the collector terminal of the first transistor 61a, and meanwhile, the other end is connected to base terminal.One end of first capacitor 61d is connected to the emitter terminal of the first transistor 61a, and meanwhile, the other end is connected to the supply lines of voltage Vr.

Second series-connection power supplies circuit 62, be provided with positive-negative-positive bipolar transistor 62a (hereinafter also referred to as " transistor seconds 62a "), the second resistance 62b, the second voltage stabilizing diode 62c (the voltage of voltage regulation Vz identical with the first voltage stabilizing diode 61c) and the second capacitor 62d.In this situation, voltage Vbe between the base-emitter terminal of transistor seconds 62a is defined as identical with the first transistor 61a, simultaneously, collector terminal is connected to the supply lines of negative voltage Vcc-, emitter terminal is connected to the outlet line of floating voltage Vf-, and base terminal is connected to the anode terminal of the second voltage stabilizing diode 62c.In addition, the cathode terminal of the second voltage stabilizing diode 62c is connected to the supply lines of voltage Vr.One end of second resistance 62b is connected to the collector terminal of transistor seconds 62a, and meanwhile, the other end is connected to base terminal.One end of second capacitor 62d is connected to the emitter terminal of transistor seconds 62a, and meanwhile, the other end is connected to the supply lines of voltage Vr.

By above formation, in power supply unit 13A, first series-connection power supplies circuit 61 generates floating voltage Vf+ (=Vr+Vz-Vbe) from positive voltage Vcc+ and exports, meanwhile, the second series-connection power supplies circuit 62 generates floating voltage Vf-(=Vr-Vz+Vbe) from negative voltage Vcc-and exports.Specifically, in the first series-connection power supplies circuit 61, first voltage stabilizing diode 61c produces voltage of voltage regulation Vz at cathode terminal after the supply of the first resistance 61b received current, base terminal is defined as the first transistor 61a of voltage of voltage regulation Vz, on emitter terminal with the anode terminal of the first voltage stabilizing diode 61c for benchmark and formation voltage (Vz-Vbe).Therefore, the first series-connection power supplies circuit 61, generates and is the floating voltage Vf+ of (Vr+Vz-Vbe) with ground potential Vg for voltage during benchmark and exports.In addition, in the second series-connection power supplies circuit 62, second voltage stabilizing diode 62c produces voltage of voltage regulation Vz at anode terminal after the supply of the second resistance 62b received current, base terminal is defined as the transistor seconds 62a of voltage of voltage regulation Vz, on emitter terminal with the anode terminal of the second voltage stabilizing diode 62c for benchmark and formation voltage (-Vz+Vbe).Therefore, the second series-connection power supplies circuit 62, generates and is the floating voltage Vf-of (Vr-Vz+Vbe) with ground potential Vg for voltage during benchmark and exports.

That is, power supply unit 13A, as long as voltage Vr change under the state that voltage (Vr+Vz-Vbe) does not reach positive voltage Vcc+ and voltage (Vr-Vz+Vbe) does not reach negative voltage Vcc-, just, while the variation of following this voltage Vr, the absolute value relative to voltage Vr is generated | the floating voltage Vf+ as positive voltage that Vz-Vbe| the is equal and floating voltage Vf-as negative voltage also exports.Therefore, each circuit in floating circuit portion 2 receive this each floating voltage Vf+, Vf-supply and normally carry out work as a result, normally export Insulation monitoring signal S2 from floating circuit portion 2.Therefore, by using this power supply unit 13A, the high price parts using accumulator or transformer etc. can be avoided, consequently can reduce the cost of products of voltage check device 1 significantly.In addition, although not shown, also known current foldback circuit or known overvoltage crowbar can be added in each series-connection power supplies circuit 61,62.

In addition, insulation division 15 is configured with above in floating circuit portion 2, and the detection signal S1 utilizing test section 14 to detect is transformed to the formation exported with the Insulation monitoring signal S2 of this detection signal S1 electrical isolation and is illustrated, but, as shown in figure 12, the formation not configuring insulation division 15 in floating circuit portion 2 can also be adopted.In this formation, also following formation can be adopted, that is: export to main body circuit portion 3 in couples from floating circuit portion 2 by the signal of detection signal S1 and expression voltage Vr, the differential amplifier circuit 63 being configured at main body circuit portion 3 inputs this detection signal S1 and voltage Vr, meanwhile, replace Insulation monitoring signal S2 and the formation that the detection signal S2a of difference of detection signal S1 and voltage Vr exports to amplifying circuit 41 will be represented.

This differential amplifier circuit 63; as one such as shown in Figure 12; the feedback resistance 63d of operational amplifier 63a, input resistance 63b, input resistance 63c, operational amplifier 63a and resistance 63e can be used and form; wherein; input resistance 63b is disposed between the inverting input of operational amplifier 63a and the amplifying circuit 22 in floating circuit portion 2; input resistance 63c is disposed between the in-phase input end of operational amplifier 63a and the guard electrode 11 in floating circuit portion 2, and resistance 63e is disposed between the in-phase input end of operational amplifier 63a and ground potential Vg.In addition, supply the power supply of each floating voltage Vf+, Vf-as each structural detail to floating circuit portion 2 in the formation shown in this Figure 12, can be used above-mentioned power supply unit 13,13A any one.

In addition, for contrast signal efferent 31, as shown in figure 11, also can adopt by adding the operational amplifier A P4 being configured to voltage follower circuit (Voltage Follower Circuit) in contrast signal efferent 31, and entirety plays a role as new contrast signal efferent, thus by formation that the contrast signal Ss that utilizes contrast signal efferent 31 to generate exports with more Low ESR.

In example described above, following form is illustrated, that is: the amplitude of the signal content of the contrast signal that the amplification detection signal exported with amplifying circuit 41 comprises, become adding or subtracting calculation of the amplification detection signal that contrast signal by exporting from contrast signal efferent 31 (or 31A or 31B) and amplifying circuit 41 export, and the value that the signal content of the contrast signal that this contrast signal and this amplification detection signal comprise is cancelled is such, and control the gain of amplifying circuit 41, and from amplification detection signal, the signal that the signal content of the contrast signal comprised by this signal is cancelled as detected object alternating voltage signal content and extract.In addition, the amplitude of the signal content of the contrast signal that the amplification detection signal that also can export with amplifying circuit 41 comprises, become the gain that prespecified fixed value controls amplifying circuit 41 like that, and from amplification detection signal extraction at least with reference to the signal content that the frequency content of signal removes.For such example, be below described.

[the 3rd example]

The voltage check device 103 that 3rd example of the present invention relates to is voltage check devices of non-contact type, be provided with floating circuit portion 2 and main body circuit portion 3A as shown in figure 13, and be configured to detect non-contactly with ground potential Vg for benchmark and the alternating voltage V1 (detected object alternating voltage) that produces in detected object 4.In addition, except the formation of signal extraction portion 32A in main body circuit portion 3A and the action of handling part 33A, other are the formation identical with the voltage check device 101 shown in Fig. 1 and action, therefore also the repetitive description thereof will be omitted to give identical symbol, is mainly described the signal extraction portion 32A different from voltage check device 101 and handling part 33A.

Signal extraction portion 32A, an example like that as shown in fig. 13 that, be provided with amplifying circuit 41, synchro detection circuit 43A, control circuit 44A and wave filter 45, and comprise with amplification detection signal S3 to become fixed amplitude (prespecified amplitude) such with the amplitude of the contrast signal Ss signal content that is same frequency, Insulation monitoring signal S2 is amplified and generates amplification detection signal S3, simultaneously, the signal content that removing is identical with contrast signal Ss from this amplification detection signal S3, and export as output signal So.In this situation; the signal content of the contrast signal Ss that so-called amplification detection signal S3 comprises; be the output to guard electrode 11 (adding) according to contrast signal Ss and signal content (that is, what amplification detection signal S3 comprised is the signal content of same frequency with contrast signal Ss) that the reference voltage composition Vs1 that comprised by detection signal S1 produces.

Specifically, amplifying circuit 41 is while isolated input detection signal S2, (gain both can be more than 1 to the magnification be prescribed with the level (DC level) according to control signal (the being specially control voltage) Sc exported from control circuit 44A, also 1 can be less than) Insulation monitoring signal S2 is amplified, thus generate amplification detection signal S3 and export.As amplifying circuit 41, the circuit shown in Fig. 3 can be used in the same manner as the first example.

Synchro detection circuit 43A, while inputting amplification detection signal S3 from amplifying circuit 41, contrast signal Ss is inputted from contrast signal efferent 31, and by utilizing this contrast signal Ss to carry out synchronous detection to this amplification detection signal S3, and generate rectified signal Vd and export.

Control circuit 44A, generate control signal Sc according to the voltage of rectified signal Vd of input and target voltage Ve (the inner voltage that generates or the voltage from outside input are the voltage inputted from the outside of control circuit 44A in this example as an example) and export.Specifically, control circuit 44A, makes level increase at the voltage of rectified signal Vd lower than during target voltage Ve, higher than during target voltage Ve, level is reduced at the voltage of rectified signal Vd, thus exports control signal Sc.By above formation, in signal extraction portion 32A, the FEEDBACK CONTROL of the gain (magnification) of amplifying circuit 41 is undertaken by synchro detection circuit 43A and control circuit 44A, control circuit 44A, become fixing with the amplitude of the inversion signal composition (be the signal content of same frequency with contrast signal Ss) forming amplification detection signal S3, and control the magnification of amplifying circuit 41 according to rectified signal Vd.In this situation, as the amplitude that this is prespecified, arbitrary value can be adopted.In addition, make the voltage in handling part 33A calculate the aftermentioned voltage used in process calculate with chart TB time, make according to numerical data D1, wherein, numerical data D1 is as prespecified amplitude using the value of this employing, and under the state of FEEDBACK CONTROL being carried out to the magnification of amplifying circuit 41 at synchro detection circuit 43A and control circuit 44A, the data obtained by handling part 33A.

Wave filter 45, inputs the amplification detection signal S3 exported from amplifying circuit 41, meanwhile, extracts the signal content of alternating voltage V1 and export as output signal So from this amplification detection signal S3.Such as, wave filter 45 is made up of passive filter circuit (Passive Filter Circuit) or active filter circuit (Active Filter Circuit), stoping with contrast signal Ss is passing through of the signal content of same frequency, and the voltage component of the detected object electric current I v1 produced based on the alternating voltage V1 by detected object 4 (be the signal content of same frequency with alternating voltage V1) is passed through, wherein, passive filter circuit or active filter circuit are configured to bandpass filter (Bandpass Filter) or low-pass filter (Low-Pass Filter).By this formation, signal extraction portion 32A, generate the output signal So that is made up of the voltage component based on detected object electric current I v1 and export, wherein, detected object electric current I v1 is the electric current produced by the alternating voltage V1 of detected object 4.

In this voltage check device 103, according to the size of the electrostatic capacitance C0 formed between detected object 4 and detecting electrode 12, the reference electric current I s1 that current signal I comprises changes with identical ratio with detected object electric current I v1, and the reference voltage composition Vs1 that detection signal S1 comprises also changes with identical ratio with detected object voltage component Vv1.Therefore, for forming the inversion signal composition (be the signal content of same frequency with contrast signal Ss) of amplification detection signal S3 and being the signal content of same frequency with alternating voltage V1, two compositions also change with identical ratio, but, in signal extraction portion 32A, by above-mentioned FEEDBACK CONTROL, amplification detection signal S3 becomes fixing with the amplitude of the inversion signal composition (be the signal content of same frequency with contrast signal Ss) forming this signal S3, and is generated by amplifying circuit 41.Therefore, in the voltage check device 103 that this example is formed, based on the voltage component of the detected object electric current I v1 that output signal So comprises, regardless of the size of electrostatic capacitance C0, its amplitude all becomes the size (proportional size) corresponding with the amplitude of the alternating voltage V1 produced in detected object 4.Therefore, from the output signal So that signal extraction portion 32A exports, the signal that the amplitude becoming the alternating voltage V1 of its amplitude and detected object 4 changes pro rata.

Handling part 33A is provided with A/D transducer and CPU (all not shown) and forms, and perform stores processor, voltage calculate process and output processing, wherein, stores processor utilizes the voltage waveform (level) of the sampling clock of assigned frequency to output signal So sample and be transformed to numerical data D1 and be stored in the process of storage part 34, it is the process calculating alternating voltage V1 according to this numerical data D1 that voltage calculates process, and output processing is the process exported by the alternating voltage V1 calculated.Storage part 34 is made up of ROM or RAM etc., and the voltage be previously stored with in handling part 33A calculates the voltage used in process calculates and use chart TB.

Being made sequentially with chart TB is calculated for the voltage in this example, its summary is described.As an example, undertaken by synchro detection circuit 43A and control circuit 44A in the FEEDBACK CONTROL of the gain (magnification) for amplifying circuit 41, and control circuit 44A to become fixing (prespecified amplitude) with the amplitude of the inversion signal composition (be the signal content of same frequency with contrast signal Ss) forming amplification detection signal S3 such, and under the state controlling the magnification of amplifying circuit 41 according to rectified signal Vd, numerical data D1 is obtained while make the amplitude of the alternating voltage V1 produced in detected object 4 change with the voltage step size of regulation, and contrast with the alternating voltage V1 changed by this voltage step size and the magnitude of voltage of numerical data D1 and alternating voltage V1 is together stored, calculate use chart TB by being made voltage like this.By this formation, handling part 33A calculates the magnitude of voltage obtaining the alternating voltage V1 corresponding with the numerical data D1 obtained with chart TB by referring to voltage, thus can calculate the alternating voltage V1 of detected object 4.Efferent 35, is made up of display device as an example in this example, and in the output processing of handling part 33A, the waveform making alternating voltage V1 or voltage parameter (amplitude or the effective value) display calculated.

Next, the detection action of the alternating voltage V1 for detected object 4 utilizing voltage check device 103 to carry out is described.

In the same manner as the first example, export the Insulation monitoring signal S2 with detection signal S1 electrical isolation from the insulation division 15 in floating circuit portion 2.In the signal extraction portion 32A of main body circuit portion 3A, as shown in figure 13, amplifying circuit 41 is while isolated input detection signal S2, the magnification be prescribed with the level according to the control signal Sc exported from control circuit 44A, Insulation monitoring signal S2 is amplified, thus the amplitude that generation and contrast signal Ss are the signal content of same frequency becomes fixing amplification detection signal S3 and exports.

As an example, first, synchro detection circuit 43A is while input amplification detection signal S3 and contrast signal Ss, by utilizing contrast signal Ss, synchronous detection is carried out to amplification detection signal S3, and generate rectified signal Vd and export, wherein, rectified signal Vd is the increase and decrease of the amplitude of the signal content of the contrast signal Ss that voltage comprises according to amplification detection signal S3 and the signal increased and decreased.

Next, control circuit 44A generates control signal Sc according to the voltage of the rectified signal Vd of input and target voltage Ve and exports.Specifically, control circuit 44A, makes level increase at the voltage of rectified signal Vd lower than during target voltage Ve, higher than during target voltage Ve, level is reduced at the voltage of rectified signal Vd, thus exports control signal Sc.By above formation, in signal extraction portion 32A, FEEDBACK CONTROL for the gain (magnification) of amplifying circuit 41 is undertaken by synchro detection circuit 43A and control circuit 44A, and control circuit 44A becomes fixing (prespecified amplitude with the amplitude of the inversion signal composition (be the signal content of same frequency with contrast signal Ss) forming amplification detection signal S3.Voltage calculates with amplitude during being made of chart TB) like that, and the magnification of amplifying circuit 41 is controlled according to rectified signal Vd.By like this, the Insulation monitoring signal S2 of input amplifies by amplifying circuit 41, and generates and contrast signal Ss is that the amplitude of the signal content of same frequency becomes the amplification detection signal S3 of fixing (above-mentioned prespecified amplitude) and exports.Then, wave filter 45, while the amplification detection signal S3 will exported from amplifying circuit 41 inputs, extracts the signal content of alternating voltage V1 and exports as output signal So from this amplification detection signal S3.

Next, handling part 33A performs stores processor, is transformed to numerical data D1 and is stored in storage part 34 while input/output signal So.Then, handling part 33A performs voltage and calculates process.Calculate in process at this voltage, handling part 33A reads the numerical data D1 being stored in storage part 34, and meanwhile, reference voltage calculates with chart TB and obtains the alternating voltage V1 corresponding with the numerical data D1 read.In addition, the alternating voltage V1 that handling part 33A obtains according to this, and calculate the effective value or amplitude etc. of such as alternating voltage V1 and be stored in storage part 34.Finally, handling part 33A performs output processing, makes the effective value of the alternating voltage V1 being stored in storage part 34 or amplitude etc. be shown in the efferent 35 be made up of display device.By like this, the detection of the alternating voltage V1 of the detected object 4 of voltage check device 103 is utilized to terminate.In addition, also can adopt in output processing, handling part 33A makes the voltage waveform of alternating voltage V1 be shown in the formation of efferent 35 according to the alternating voltage V1 obtained.

In this example, contrast signal efferent 31 exports contrast signal Ss to guard electrode 11, receive floating voltage Vf+, the supply of Vf-and carry out the test section 14 of work, the detection signal S1 that amplitude carries out according to the electric potential difference (V1-Vr) exchanged changing is exported according to current signal 1, wherein, current signal I be by detecting electrode 12 between detected object 4 and guard electrode 11, the current signal circulated is carried out with the current value that the electric potential difference (V1-Vr) with the interchange between alternating voltage V1 and the voltage Vr of guard electrode 11 is corresponding, insulation division 15 inputs detection signal S1 and exports as Insulation monitoring signal S2, signal extraction portion 32A comprise with Insulation monitoring signal S2 to become prespecified amplitude such with the amplitude of the signal content of contrast signal Ss same frequency, namely become like that fixing, and control the amplitude of Insulation monitoring signal S2 and export as amplification detection signal S3, simultaneously, by amplitude adding or subtracting calculation by the amplification detection signal S3 controlled like this and the contrast signal Ss exported from contrast signal efferent 31, and removing with the signal content of contrast signal Ss same frequency that amplification detection signal S3 is comprised, thus export as output signal So.

Therefore, adopt the words of this example, the amplitude of amplification detection signal S3 is controlled to become like that fixing with the amplitude of the contrast signal Ss signal content that is same frequency by signal extraction portion 32A, even if the coupling capacitance (electrostatic capacitance C0) between detected object 4 and detecting electrode 12 is unknown (value regardless of electrostatic capacitance C0), also the sensitivity be controlled as alternating voltage V1 becomes fixing sensitivity, namely the amplitude being controlled as the voltage component of the detected object electric current I v1 comprised based on output signal So becomes the size corresponding with the amplitude of alternating voltage V1, therefore, by detecting this voltage component that output signal So comprises, calculating of electrostatic capacitance C0 need not be carried out, also alternating voltage V1 can be detected non-contactly.

In addition, in this example, in signal extraction portion 32A, synchro detection circuit 43A is by employing the synchronous detection of contrast signal Ss, and detecting the rectified signal Vd of the amplitude of the signal content representing the relevant contrast signal Ss that amplification detection signal S3 comprises, control circuit 44A controls the gain of amplifying circuit 41 according to this rectified signal Vd.Therefore, adopt the words of this example, the signal content of contrast signal S correctly can be detected by synchronous detection, consequently, the amplitude controlling of the signal content of the contrast signal Ss that can be comprised by amplification detection signal S3 is accurately fixing, therefore, it is possible to improve the accuracy of detection of alternating voltage V1 further.

In addition, as extracting the signal content of alternating voltage V1 from amplification detection signal S3 and the gimmick of generating output signal So, also the gimmick of amplification detection signal S3 being carried out to digital signal processing in handling part 33A can be adopted, adopt the words of this example, by being configured to use the wave filter 45 that can be made up of the known filtering circuit with above-mentioned characteristic to extract alternating voltage V1, simultaneously simple in formation, can generate with low cost the output signal So be made up of the voltage component produced according to detected object electric current I v1.In addition, adopting this example, by changing target voltage Ve, the scope of detectable alternating voltage V1 can be changed.

In addition, adopt the words of this example, by being provided with the handling part 33A detecting alternating voltage V1 according to output signal So, alternating voltage V1 can be detected at certain intervals to handling part 33A, or make the alternating voltage V1 detected be stored in storage part 34 and preserve, or make the voltage waveform of alternating voltage V1 be shown in efferent 35 according to the alternating voltage V1 being stored in storage part 34.

In addition, in this example, handling part 33A calculates the magnitude of voltage of alternating voltage V1 according to output signal So.As an example, handling part 33A inputs the output signal So be made up of the voltage component produced according to detected object electric current I v1 (be namely the voltage component of same frequency with the frequency of alternating voltage V1), and obtain its numerical data D1, calculate the magnitude of voltage obtaining the alternating voltage V1 corresponding with the numerical data D1 obtained with chart TB by referring to voltage, and calculate the alternating voltage V1 of detected object 4.Therefore, adopt this example, the magnitude of voltage of alternating voltage V1 itself can be detected.

In the 3rd example described above, have employed by by detecting electrode 12, power supply unit 13, test section 14 and insulation division 15 are contained in guard electrode 11, and do not form floating circuit portion 2 with main body circuit portion 3 consubstantiality, thus while raising CMRR (Common Mode Rejection Ratio), the formation of the detection of the alternating voltage V1 of high pressure can be carried out, but, when not needing to make test section 14 to carry out work with quick condition (such as, alternating voltage V1 is comparatively low pressure, or when not being required high CMRR), also can adopt in the same manner as the second example and not use guard electrode 11, the formation of power supply unit 13 and insulation division 15.Below, such example is described.

[the 4th example]

As shown in figure 14, the voltage check device 104 that 4th example of the present invention relates to, replace the floating circuit portion 2 of the voltage check device 103 that the 3rd example relates to, and be provided with detecting electrode 12 and test section 14A in the same manner as the voltage check device 102 related to the second example.Therefore, voltage check device 104 is provided with detecting electrode 12, test section 14 and main body circuit portion 3A, and is configured to detect non-contactly the alternating voltage V1 produced in detected object 4.In addition, for detecting electrode 12 and main body circuit portion 3A, form, for test section 14 identically with the voltage check device 103 that the 3rd example relates to, form, also the repetitive description thereof will be omitted thus to give identical symbol identically with the voltage check device 102 that the second example relates to.

The voltage check device 103 that multiple 3rd example relates to can be utilized, the line voltage distribution pick-up unit 51 shown in pie graph 8 in the same manner as the voltage check device 101 that the first example relates to.In addition, the voltage check device 104 that multiple 4th example relates to can be utilized, the line voltage distribution pick-up unit 51A shown in pie graph 9 in the same manner as the voltage check device 102 that the second example relates to.

In order to improve the reliability for the alternating voltage detected, the function whether detection (measurement) action that also can arrange inspection (diagnosis) voltage is normally carried out.Below, such example is described.

[the 5th example]

The voltage check device 105 that 5th example of the present invention relates to is voltage check devices of non-contact type, as shown in figure 15, be provided with floating circuit portion 2 and main body circuit portion 3B, and be configured to detect non-contactly with ground potential Vg for benchmark and the alternating voltage V1 (detected object alternating voltage) that produces in detected object 4.In addition, except except being provided with the action of the handling part 33B in wave filter 38 and main body circuit portion 3B in main body circuit portion 3B, other are the formation identical with the voltage check device 101 shown in Fig. 1 and action, therefore, also the repetitive description thereof will be omitted to give identical symbol, is mainly described the part different from voltage check device 101.

Wave filter 38 optionally makes to be the wave filter (be bandpass filter as an example) that the signal content of same frequency passes through with contrast signal Ss, as shown in phantom in Figure 15, input at the Insulation monitoring signal S2 detected as the A point from insulation division 15 to the input point in signal extraction portion 32, meanwhile, extract the signal content Ss2 of the contrast signal Ss that Insulation monitoring signal S2 comprises and export to handling part 33B.

Handling part 33B is provided with A/D transducer and CPU (all not shown) and forms, and perform stores processor, voltage calculate process and output processing, wherein, stores processor utilizes the voltage waveform (level) of the sampling clock of assigned frequency to output signal So sample and be transformed to numerical data D1 and be stored in the process of storage part 34, it is the process calculating alternating voltage V1 according to this numerical data D1 that voltage calculates process, and output processing is the process exported by the alternating voltage V1 calculated.In addition, handling part 33B plays a role as judging part, the voltage waveform of the signal content Ss2 exported from wave filter 38 is transformed to numerical data, and detect its level (DC level (absolute value of DC voltage) after the amplitude level of this signal content Ss2 or the rectification of this signal content Ss2), compared by the level Va that detects this (be amplitude level as an example) and prespecified specified level Vre, and execution is for the diagnostic process of the detection action of the alternating voltage V1 in voltage check device 105.

In this situation, in voltage check device 105, when under the state that device normally carries out work, detecting electrode 12 and detected object 4 have carried out capacitive coupling, become the current signal I (being specially with reference to electric current I s1) produced by the contrast signal Ss exported from contrast signal efferent 31 to circulate between detected object 4 and floating circuit portion 2, the signal content produced by this reference electric current I s1 is often contained in the state in Insulation monitoring signal S2 and amplification detection signal S3.Therefore, as an example, by the lower limit of the above-mentioned level Va of contrast signal Ss in advance Insulation monitoring signal S2 during this regular event comprised, as specified level Vre theoretical property ground or tentatively calculate and be stored in storage part 34, the following at least one process (be two kinds as an example in this example and judge process) judged in process performs as above-mentioned diagnostic process by handling part 33B, by like this, the action of voltage check device 105 can be diagnosed to be normal (normally carrying out the detection action of alternating voltage V1) or abnormal (normally not carrying out the detection action of alternating voltage V1), wherein, judge process, be judged as that when the level Va of the signal content Ss2 of the contrast signal Ss detected is more than specified level Vre the action of device is that normal (action is normal) judges process, with the judgement process being judged as the danger (remarkable action) that the action existence generation of device is abnormal when the level Va of the signal content Ss2 detected is less than specified level Vre.

The basic action of this voltage check device 105 is identical with the action of the voltage check device 101 that the first example shown in Fig. 1 relates to.In this action, wave filter 38 performs continuously while isolated input detection signal S2, extract the signal content Ss2 of the contrast signal Ss that Insulation monitoring signal S2 comprises and the action exported to handling part 33B, handling part 33B, calculates process with the stores processor in the first example and voltage and side by side performs the diagnostic process using the signal content Ss2 exported from wave filter 38.In this diagnostic process, first the voltage waveform of the signal content Ss2 of input is transformed to numerical data by handling part 33B, and detect the level Va amplitude level of signal content Ss2 (in this example for) of signal content Ss2, and the level Va that this is detected and comparing from the specified level Vre that storage part 34 reads.Then, handling part 33B, when the result that this compares be level Va is more than specified level Vre, be judged as that the action of device is normal (action is normal), when level Va is less than specified level Vre, be judged as that the action of device exists abnormal (remarkable action), and this judged result is stored in storage part 34.Terminated by such diagnostic process.

Finally, handling part 33B performs output processing, will be stored in the effective value or amplitude etc. of the alternating voltage V1 of storage part 34, and together be shown in the judged result in diagnostic process the efferent 35 be made up of display device.By like this, the detection of the alternating voltage V1 to detected object 4 of voltage check device 105 is utilized to terminate.In addition, also following formation can be adopted, that is: in output processing, when the judged result of handling part 33B in diagnostic process is judged as that action is normal, the effective value of alternating voltage V1 or amplitude etc. are shown in efferent 35, when judged result in diagnostic process is judged as remarkable action, only makes judgment result displays in diagnostic process in efferent 35, and the effective value of alternating voltage V1 or amplitude etc. are not shown in the formation of efferent 35.

Adopt the words of this example; process is judged because handling part 33B performs; therefore; the diagnosis (judgement) whether the result that operator can process according to this judgement and the detection action carrying out voltage in voltage check device 105 are normally carried out; wherein; judge process; while the level Va (amplitude level of signal content Ss2) of the signal content Ss2 detecting the relevant contrast signal Ss that Insulation monitoring signal S2 comprises; compare with specified level Vre, thus judge that the action of voltage check device 105 is normal or abnormal process.Therefore, adopt this example, due to the alternating voltage V1 that operator can be made to distinguish detect be action normal time voltage or remarkable action time voltage, therefore, it is possible to improve the reliability for the alternating voltage V1 detected.

In addition, at this, illustrate the Insulation monitoring signal S2 adopting handling part 33B to detect according to the A point in the input point as signal extraction portion 32, perform the example of the formation of the diagnosis of voltage check device 105 and be illustrated, but, as described above by the signal content produced with reference to electric current I s1, be not only contained in Insulation monitoring signal S2, be also contained in amplification detection signal S3.Therefore, the amplification detection signal S3 that handling part 33B also can be adopted to detect according to the B point at the output point as amplifying circuit 41 and perform the formation of diagnostic process.In this formation, as shown in phantom in Figure 15, wave filter 38, while B point input amplification detection signal S3, extracts the signal content of the contrast signal Ss that amplification detection signal S3 comprises, and exports to handling part 33B as signal content Ss2.Handling part 33B, in the same manner as perform the situation of the diagnosis of voltage check device 105 according to the Insulation monitoring signal S2 detected at A point, perform the diagnostic process using the signal content Ss2 exported from wave filter 38, be judged as that when the level Va of signal content Ss2 is more than specified level Vre the action of device is normal (action is normal), be judged as that when level Va is less than specified level Vre the action of device exists abnormal (remarkable action), and this judged result is stored in storage part 34.As specified level Vre now, calculate the lower limit of the above-mentioned level Va of the contrast signal Ss that amplification detection signal S3 comprises when the regular event of voltage check device 105 in advance and use.

In addition, in voltage check device 105, when regular event, FEEDBACK CONTROL for the gain (magnification) of amplifying circuit 41 is undertaken by synchro detection circuit 43 and control circuit 44, the amplitude forming the inversion signal composition (be the signal content of same frequency with contrast signal Ss) of amplification detection signal S3 is controlled as, be identical amplitude with the amplitude of the contrast signal Ss being transfused to adding circuit 42 as reference signal Sr, by like this, in adding circuit 42, the inversion signal composition forming amplification detection signal S3 is referenced signal Ss and offsets (elimination).That is, not only output signal the level (such as amplitude level) of the signal content of the reference signal Sr (being reference wire size Ss in this example) that So comprises, and also become low level from the level (DC level) of the rectified signal Vd of synchro detection circuit 43 output.On the other hand, such as floating circuit portion 2 or for the feedback control action of the gain (magnification) of amplifying circuit 41 in produce abnormal time the remarkable action of the voltage check device 105 (time), the level not only outputing signal the signal content of the reference signal Sr that So comprises becomes high level, and also becomes high level from the level (DC level) of the rectified signal Vd of synchro detection circuit 43 output.

Therefore, also following formation can be adopted, that is: handling part 33B, the output signal So detected according to the C point at the output point as adding circuit 42 and at least one signal of rectified signal Vd detected at the D point of the output point as synchro detection circuit 43, and perform the formation of the diagnosis of voltage check device 105.In this situation, performing in the formation of diagnosis according to output signal So, as shown in phantom in Figure 15, wave filter 38 is while C point input/output signal So, extract the signal content of the contrast signal Ss that output signal So comprises, and export to handling part 33B as signal content Ss2.In the diagnostic process of the output signal So detected based on C point, when handling part 33B and the diagnostic process based on the Insulation monitoring signal S2 detected at A point on the contrary, when the level Va of signal content Ss2 is below specified level Vre, be judged as that the action of device is normal (action is normal), when level Va exceedes specified level Vre, be judged as that the action of device exists abnormal (remarkable action), and this judged result is stored in storage part 34.As specified level Vre now, output signal the higher limit of the above-mentioned level Va of the contrast signal Ss that So comprises and use when calculating the regular event of voltage check device 105 in advance.

In addition, performing in the formation of diagnosis according to rectified signal Vd, as shown in phantom in Figure 15, handling part 33B is while D point input rectified signal Vd, in the same manner as the diagnostic process based on the output signal So detected at C point, when level (being also described as level Va for this level) Va of rectified signal Vd is below specified level Vre, be judged as that the action of device is normal (action is normal), when level Va exceedes specified level Vre, be judged as that the action of device exists abnormal (remarkable action), and this judged result is stored in storage part 34.As specified level Vre now, the higher limit of the above-mentioned level Va of rectified signal Vd when calculating the regular event of voltage check device 105 in advance and using.

[the 6th example]

The voltage check device 106 that 6th example of the present invention relates to, is provided with floating circuit portion 2 and main body circuit portion 3C as shown in figure 16, and is configured to detect non-contactly the alternating voltage V1 produced in detected object 4.

The voltage check device 106 that 6th example of the present invention relates to is voltage check devices of non-contact type, be provided with floating circuit portion 2 and main body circuit portion 3C as shown in figure 16, and be configured to detect non-contactly the alternating voltage V1 produced in detected object 4.Formation in main body circuit portion 3C, it is formation identical with the voltage check device 105 shown in Figure 15 except signal extraction portion 32A, the formation of signal extraction portion 32A be with Figure 13, Figure 14 respectively shown in voltage check device 103,104 identical formations, because the explanation of its formation and action repeats, therefore omit.

[the 7th example]

In addition, even if the voltage check device 107 that the 7th example as shown in figure 17 relates to is such, adopt and export while according to Insulation monitoring signal S2 formation voltage signal S4 (adding) to guard electrode 11, and carry out the formation of FEEDBACK CONTROL like that close to alternating voltage V1 with the voltage V4 of this voltage signal S4, with first, second and the 5th the voltage check device 101 that relates to of each example, the formation that the basic comprising of 102 and 105 uses together, also the alternating voltage V1 of detected object 4 can be detected non-contactly, and, in the same manner as voltage check device 105, handling part 33B can according at A, B, C, any one and the diagnostic process performed voltage check device 107 of each signal that D point detects.

Below, the voltage check device 107 that this example relates to is described from Figure 17 with reference to Fig. 5 ~ Figure 22.In addition, for the formation identical with the voltage check device 106 that the 6th example relates to, also the repetitive description thereof will be omitted to give identical symbol.

Voltage check device 107 is voltage check devices of non-contact type, be provided with floating circuit portion 2 and main body circuit portion 3D as shown in figure 17, and be configured to detect non-contactly with ground potential Vg for benchmark and the alternating voltage V1 (detected object alternating voltage) that produces in detected object 4.

As shown in figure 17, floating circuit portion 2 is provided with guard electrode 11, detecting electrode 12, power supply unit 13, test section 14 and insulation division 15, and identical to form with voltage check device 105,106.In this floating circuit portion 2, test section 14, according to the current signal I (detection electric current) carrying out circulating with the current value corresponding with the electric potential difference (V1-Vr) exchanged, generates the detection signal S1 of its amplitude change according to the electric potential difference (V1-Vr) exchanged and exports.In this situation, export (add) contrast signal Ss via capacitor 31a to guard electrode 11 from contrast signal efferent 31 described later, meanwhile, export (adding) voltage signal S4 from feedback control section 37 described later.By this formation, voltage Vr becomes the resultant voltage of voltage (feedback voltage) V4 of voltage signal S4 and the voltage Vs of contrast signal Ss.By like this, above-mentioned current signal I, by the reference electric current I s1 produced by contrast signal Ss, the current signal composition produced by voltage signal S4 is (following, also referred to as " FB current component ") Ib1, and the detected object electric current I v1 to be produced by the alternating voltage V1 of detected object 4 and forming, based on the detection signal S1 of this current signal I, also by the reference voltage composition Vs1 based on reference electric current I s1, voltage signal composition based on FB current component Ib1 is (following, also referred to as " FB voltage component ") Vb1, and based on detected object electric current I v1 detected object voltage component Vv1 and form.In addition; detection signal S1 is generated because test section 14 carries out action using the voltage carrying out the guard electrode 11 changed by referring to the voltage Vs of signal Ss and the voltage V4 of voltage signal S4 as benchmark; therefore; it is anti-phase signal that the reference voltage composition Vs1 that detection signal S1 comprises becomes relative to contrast signal Ss, and it is anti-phase signal that the FB voltage component Vb1 that detection signal S1 comprises also becomes relative to voltage signal S4.

Insulation division 15, carries out electrical isolation and exports as Insulation monitoring signal S2 while input detection signal S1.Below the floating circuit portion 2 formed like that, in the wide frequency band range from low frequency (number Hz) paramount frequency (hundreds of Hz), there is flat frequency characteristic, and as described above, detect to carry out the current signal I (detection electric current) circulated with current value corresponding to electric potential difference (V1-Vr) exchanged, thus generate Insulation monitoring signal S2 that its amplitude changes according to the electric potential difference (V1-Vr) of this interchange and export.

As shown in figure 17, main body circuit portion 3D is provided with contrast signal efferent 31, signal extraction portion 32, handling part 33B, storage part 34, efferent 35, amplitude changing unit 36 and feedback control section 37.In this situation, contrast signal efferent 31 generates contrast signal Ss (AC signal that frequency and amplitude are fixed) and exports to guard electrode 11 via capacitor 31a.In this example, as an example, the frequency f s of contrast signal Ss be defined in as described later exceed can responsive feedback control part 37 frequency band W1,2 frequency band W3 in (with reference to Figure 18).Amplitude changing unit 36 is made up of attenuator (as an example two resistance 36a, 36b for being connected in series); and using the voltage Vr of guard electrode 11 as while voltage signal Sr inputs, change (k doubly: k is arithmetic number) its amplitude and also export as reference signal Sr1.

Signal extraction portion 32, amplifying circuit 41 is provided with as an example, adding circuit 42, synchro detection circuit 43 and control circuit 44, Insulation monitoring signal S2 is amplified with the gain of regulation and generates amplification detection signal S3, and gain when passing through the amplification controlling Insulation monitoring signal S2, generate the output signal So that is made up of the signal content of alternating voltage V1 as described later and export, wherein, the control of the gain during amplification of Insulation monitoring signal S2, using can adding or subtracting and calculate (in this example as an example for adding) by amplification detection signal S3 and reference signal Sr1, and the signal content of the contrast signal Ss comprised by amplification detection signal S3 is (following, also referred to as the first signal content) and the signal content of the contrast signal Ss that comprises of reference signal Sr1 (following, also referred to as secondary signal composition) offset like that and carry out.In this situation; first signal content of the contrast signal Ss that so-called amplification detection signal S3 comprises; be the output to guard electrode 11 (adding) according to contrast signal Ss and signal content (that is, what amplification detection signal S3 comprised is the signal content of same frequency with contrast signal Ss) that the reference voltage composition Vs1 that comprised by detection signal S1 produces.In addition; the secondary signal composition of the contrast signal Ss that so-called reference signal Sr1 comprises, is the output to guard electrode 11 (adding) according to contrast signal Ss and is the signal content of same frequency with the contrast signal Ss that reference signal Sr1 comprises.

Two signal S3, Sr1 are added by adding circuit 42 while input amplification detection signal S3 and reference signal Sr1, and are exported as output signal So by the signal that adds obtained by adding.In this situation, as described above, detection signal S1, by being anti-phase reference voltage composition Vs1 relative to contrast signal Ss, being anti-phase FB voltage component Vb1 and forming with the detected object voltage component Vv1 that alternating voltage V1 is homophase relative to voltage signal S4.Therefore, the Insulation monitoring signal S2 generated according to detection signal S1 and the amplification detection signal S3 being amplified by Insulation monitoring signal S2 and generate, also by being anti-phase signal content relative to contrast signal Ss, being anti-phase signal content and forming with the signal content that alternating voltage V1 is homophase relative to voltage signal S4.In this situation, amplification detection signal S3 is controlled as, what self comprise is that anti-phase the first signal content is (following relative to contrast signal Ss, also referred to as " inversion signal composition ") amplitude, by aftermentioned final like that become with the amplitude of the secondary signal composition of the contrast signal Ss that the reference signal Sr1 exported from amplitude changing unit 36 comprises (with reference to signal Ss amplitude K doubly after amplitude: k × Ss) identical amplitude.

On the other hand, voltage Vr due to voltage signal Sr is the resultant voltage of the voltage V4 of voltage signal S4 and the voltage Vs of contrast signal Ss as described above, therefore, by the amplitude k of this voltage signal Sr doubly reference signal Sr1 generated, by the signal content (signal with reference to after amplitude k times of signal Ss) relative to contrast signal Ss being homophase, and form relative to the signal content (signal by after the amplitude k of voltage signal S4 times) that voltage signal S4 is homophase.

Therefore, by utilizing the process that adds of two signal S3, Sr1 of adding circuit 42, form the inversion signal composition (the first signal content) of the contrast signal Ss of amplification detection signal S3 and be cancelled (elimination) relative to the secondary signal composition (hereinafter also referred to as " in-phase signal composition ") that the contrast signal Ss forming reference signal Sr1 is homophase.Therefore, output signal So, to comprise relative to voltage signal S4 be anti-phase signal content and be the signal content of homophase relative to alternating voltage V1 and form the signal content of amplification detection signal S3, and relative to voltage signal S4 be homophase signal content and form reference signal Sr1 signal content (by the amplitude k of voltage signal S4 doubly after signal) form.

Synchro detection circuit 43, while input/output signal So and contrast signal Ss, by utilizing contrast signal Ss to carry out synchronous detection to output signal So, and generates rectified signal Vd and exports.Control circuit 44, the control signal Sc that formation voltage increases and decreases according to the polarity of the rectified signal Vd of input also exports to amplifying circuit 41.

By above formation, in signal extraction portion 32, FEEDBACK CONTROL for the gain (magnification) of amplifying circuit 41 is undertaken by synchro detection circuit 43 and control circuit 44, control circuit 44, becoming with the amplitude of the inversion signal composition (being same frequency with contrast signal Ss and the first anti-phase signal content) forming amplification detection signal S3 fixes like that (in this example, such with the amplitude that the amplitude of the in-phase signal composition become with formed the reference signal Sr1 being transfused to adding circuit 42 (being same frequency and the secondary signal composition of homophase with contrast signal Ss) is identical), and the magnification of amplifying circuit 41 is controlled according to rectified signal Vd.By like this, form the amplitude of the inversion signal composition of amplification detection signal S3, consistent with the amplitude of in-phase signal composition of the reference signal Sr1 being transfused to adding circuit 42.Therefore, adding circuit 42 generating output signal So exporting as described above, wherein, So is outputed signal by being anti-phase signal content relative to voltage signal S4, being the signal content of homophase (the above signal content for forming amplification detection signal S3) relative to alternating voltage V1 and being signal content (forming the signal content of the reference signal Sr1) formation of homophase relative to voltage signal S4.

In this situation, according to the size of the electrostatic capacitance C0 formed between detected object 4 and detecting electrode 12, the reference electric current I s1 that current signal I comprises changes with identical ratio with detected object electric current I v1, and the reference voltage composition Vs1 that detection signal S1 comprises also changes with identical ratio with detected object voltage component Vv1.Therefore, for forming the inversion signal composition (be the signal content of same frequency with contrast signal Ss) of amplification detection signal S3 and being the signal content of same frequency with alternating voltage V1, two compositions also change with identical ratio, but, in signal extraction portion 32, by above-mentioned FEEDBACK CONTROL, amplification detection signal S3 is consistent with the amplitude of the in-phase signal composition (secondary signal composition) being formed reference signal Sr1 with the amplitude forming the inversion signal composition (the first signal content) of this signal S3, and is generated by amplifying circuit 41.Therefore, in the formation of this example, based on the detected object electric current I v1 that comprises of output signal So voltage component, namely form the signal content (be anti-phase signal content relative to voltage signal S4 and be the signal content of homophase with alternating voltage V1) of amplification detection signal S3, regardless of the size of electrostatic capacitance C0, its amplitude all becomes the size corresponding with the difference of the alternating voltage V1 produced in detected object 4 and voltage signal S4.In addition, the formation reference signal Sr1's that output signal So comprises is the signal content of homophase relative to voltage signal S4, is the signal content independently produced with the size of electrostatic capacitance C0 originally.Therefore, output signal So to become not by the signal that the size of electrostatic capacitance C0 affects.

Feedback control section (voltage generation circuit) 37, is amplified by isolated input detection signal S2, and the voltage signal S4 of formation voltage V4 (feedback voltage) also exports (adding) to guard electrode 11.In this situation; feedback control loop is formed together with the guard electrode 11 in feedback control section 37 and floating circuit portion 2, detecting electrode 12, test section 14 and insulation division 15; and amplify the amplification action of Insulation monitoring signal S2 by carrying out making the electric potential difference Vdi of the voltage Vr of alternating voltage V1 and guard electrode 11 reduce like that, and formation voltage signal S4.In this example, as an example, feedback control section 37 is provided with ac amplifier circuit 37a, phase compensating circuit 37b and booster circuit 37c and forms.At this, ac amplifier circuit 37a, is undertaken amplifying and formation voltage signal V4a by isolated input detection signal S2.In this situation, ac amplifier circuit 37a is by amplifying action, and absolute value and the increase of the absolute value of the magnitude of voltage of Insulation monitoring signal S2 of formation voltage value reduce corresponding and carry out the voltage signal V4a that changes.

Phase compensating circuit 37b, in order to seek the stabilization (prevent vibration) of feedback control action, and input voltage signal V4a exporting as voltage signal V4b after adjusting its phase place.Booster circuit 37c, uses step-up transformer and forming as an example, and by specify that multiplying power is by voltage signal V4b boosting (making absolute value increase by not changing polarity), and formation voltage signal S4 exporting to guard electrode 11.In addition, booster circuit 37c, its output impedance is defined as high impedance.The feedback control section 37 of such formation, generating amplitude carries out with the frequency characteristic shown in Figure 18 the voltage signal S4 that changes and exports.According to this frequency characteristic, feedback control section 37 is followed well for the signal (alternating voltage V1) of the frequency of the frequency band W1 of the lower frequency side in the frequency band W1,2 that can respond, and generates the voltage signal S4 of the voltage V4 identical with alternating voltage V1 and export.In addition, the signal (alternating voltage V1) of the frequency that feedback control section 37 comprises for the frequency band W2 of the high frequency side in the frequency band W1,2 that can respond, generates the voltage signal S4 of the voltage V4 not reaching alternating voltage V1 because gain is not enough and exports.In addition, feedback control section 37 is not followed on earth for the signal (comprising contrast signal Ss) of the frequency band W3 exceeding frequency band W2, and formation voltage V4 is almost the voltage signal S4 of zero volt and exports.

Handling part 33B, execution stores processor, voltage calculate process, output processing and diagnostic process, wherein, stores processor utilizes the voltage waveform (level) of the sampling clock of assigned frequency to output signal So sample and be transformed to numerical data D1 and be stored in the process of storage part 34, it is the process calculating alternating voltage V1 according to this numerical data D1 that voltage calculates process, output processing is the process exported by the alternating voltage V1 calculated, and diagnostic process is the process of the level Va based on the signal content Ss2 from wave filter 38.In storage part 34, be previously stored with and calculate at the voltage of handling part 33B the voltage used in process and calculate specified level Vre with using in chart TB and diagnostic process.

Next, to utilize voltage check device 107, the detection action of the alternating voltage V1 of detected object 4 is described.

First, relative with detected object 4 with non-contacting state with detecting electrode 12, floating circuit portion 2 (or voltage check device 1B is overall) is positioned near detected object 4.By like this, as shown in figure 17, become the state being formed with electrostatic capacitance C0 between detecting electrode 12 and detected object 4.In this situation, the capacitance of electrostatic capacitance C0, with the distance of detecting electrode 12 and detected object 4 inversely proportional change, but, once after being arranged in floating circuit portion 2, under the condition that the environment of temperature etc. is certain, become fixed value (not changing).In addition, due to electrostatic capacitance C0 capacitance generally minimum (such as count pF ~ tens of about pF), therefore, even if the frequency of alternating voltage V1 is hundreds of about Hz, the impedance between detected object 4 and detecting electrode 12 also becomes very large value (number M Ω).Therefore; in this voltage check device 107; even if in the situation (situation that electric potential difference Vdi is large) that the alternating voltage V1 of the detected object 4 and voltage Vr of guard electrode 11 differs widely; also can use the product of the resistance to cheapness forced down of input in the operational amplifier 21a (with reference to Fig. 2) forming test section 14, in this formation, also can avoid the destruction of the operational amplifier 21a caused by electric potential difference Vdi.

In addition; be connected by AC deposition via electrostatic capacitance C0 with detected object 4 by detecting electrode 12, and formed from ground potential Vg via detected object 4, detecting electrode 12, test section 14, guard electrode 11, capacitor 31a, contrast signal efferent 31 and feedback control section 37 the current path A (path shown in Figure 17 chain lines) of the ground potential Vg that arrives.Therefore; under the duty in floating circuit portion 2 and main body circuit portion 3; in this current path A, circulation has current signal I; wherein, the reference electric current I s1, the detected object electric current I v1 produced because of the alternating voltage V1 of detected object 4 that are produced by the voltage Vs because of contrast signal Ss of current signal I and FB current component Ib1 from feedback control section 37 to guard electrode 11 that produce because of the voltage V4 of the voltage signal S4 exported from is formed.

By like this, in floating circuit portion 2, as shown in Figure 17 and Fig. 2, the integrating circuit 21 of test section 14 is formation voltage signal S0 by current signal I integration, and this voltage signal S0 amplifies and exports as detection signal S1 by amplifying circuit 22.In addition, insulation division 15, inputs this detection signal S1 and exports as the Insulation monitoring signal S2 with detection signal S1 electrical isolation.

In addition, in main body circuit portion 3, feedback control section 37 is formation voltage signal S4 exporting to guard electrode 11 according to this Insulation monitoring signal S2.In this situation; feedback control section 37 generating amplitude carries out the voltage signal S4 changed with the frequency characteristic shown in Figure 18; namely in low-frequency band W1, the amplitude identical with alternating voltage V1 is become; in high frequency band W3, amplitude is zero; in the frequency band W2 of centre, amplitude is along with the rising of frequency from the voltage signal S4 that the state identical with alternating voltage V1 reduces gradually to zero, and exports to guard electrode 11.Amplitude changing unit 36; the voltage Vr (resultant voltage of the voltage V4 of voltage signal S4 and the voltage Vs of contrast signal Ss) produced in guard electrode 11 is inputted as voltage signal Sr; and by changing (k doubly) its amplitude, and export as the reference signal Sr1 of the frequency characteristic shown in Figure 19.

In addition; feedback control section 37 carries out action as described above; and generate the voltage signal S4 of the frequency characteristic shown in Figure 18 and export to guard electrode 11; therefore; the Insulation monitoring signal S2 that floating circuit portion 2 generates according to the electric potential difference Vdi of alternating voltage V1 and this voltage signal S4 as described above; become about the signal content (with alternating voltage V1 identical frequency content) of alternating voltage V1 with voltage signal S4, the signal that amplitude changes with the frequency characteristic (with reference to Figure 20) contrary with the frequency characteristic (with reference to Figure 18) of voltage signal S4.That is, floating circuit portion 2 generates Insulation monitoring signal S2 and exports, wherein, Insulation monitoring signal S2 as shown in figure 20, in low-frequency band W1, because by the voltage V4 of voltage signal S4 is feedback controlled to the voltage identical with alternating voltage V1, electric potential difference Vdi is zero, therefore amplitude is zero, in high frequency band W3, because by the voltage V4 of voltage signal S4 is almost nil, electric potential difference Vdi becomes alternating voltage V1, therefore the amplitude proportional with alternating voltage V1 is become, in the frequency band W2 of centre, little by little increase to the amplitude frequency band W3 from the state of zero along with the rising of frequency.In signal extraction portion 32, as described above, FEEDBACK CONTROL for the gain (magnification) of amplifying circuit 41 is undertaken by synchro detection circuit 43 and control circuit 44, control circuit 44, becoming with the amplitude of the inversion signal composition (being same frequency with contrast signal Ss and the first anti-phase signal content) forming amplification detection signal S3 fixes like that (in this example, such with the amplitude that the amplitude of the in-phase signal composition become with formed the reference signal Sr1 being transfused to adding circuit 42 (being same frequency and the secondary signal composition of homophase with contrast signal Ss) is identical), and the magnification of amplifying circuit 41 is controlled according to rectified signal Vd.By like this, amplifying circuit 41 generates amplification detection signal S3 and exports, wherein, amplification detection signal S3 is the amplitude of the inversion signal composition signal consistent with the amplitude of in-phase signal composition of the reference signal Sr1 being transfused to adding circuit 42, and has the frequency characteristic shown in Figure 21.In this situation, the amplitude of the amplification detection signal S3 in frequency band W3, as as shown in same figure, become the k of alternating voltage V1 doubly, and become state consistent with the amplitude (k of alternating voltage V1 doubly) of the reference signal Sr1 in frequency band W1 as shown in Figure 19.

Therefore, as shown in figure 22, adding circuit 42, by in the reference signal Sr1 (signal be made up of the signal content relative to voltage signal S4 being homophase) of the frequency characteristic (with the characteristic represented by dot-and-dash line in Figure 20) shown in above-mentioned Figure 19, the amplification detection signal S3 (by the signal relative to voltage signal S4 being anti-phase signal content and formed relative to the signal content that alternating voltage V1 is homophase) of the frequency characteristic (with the characteristic represented by thin solid line in Figure 22) shown in above-mentioned Figure 21 that adds, generate and be only made up of the signal content relative to alternating voltage V1 being homophase, and in the wide frequency band range from low-frequency band W1 paramount frequency band W3 flat frequency characteristic (with the characteristic represented by thick solid line in Figure 22) output signal So (amplitude becomes the k signal doubly of the amplitude of alternating voltage V1 in broadband) and export.In this situation, each signal content of the relevant contrast signal Ss that amplification detection signal S3 and reference signal Sr1 comprises, as shown in dotted line thick in Figure 22, due to the state consistent in mutual amplitude, is therefore cancelled.

Next, handling part 33B performs stores processor, is transformed to numerical data D1 and is stored in storage part 34 while being inputted by output signal So.Then, handling part 33B performs voltage and calculates process.Calculate in process at this voltage, handling part 33B is while reading is stored in the numerical data D1 of storage part 34, and reference voltage calculates with chart TB and obtains the alternating voltage V1 corresponding with the numerical data D1 read.In addition, the alternating voltage V1 that handling part 33B obtains according to this, calculates the effective value or amplitude etc. of such as alternating voltage V1 and is stored in storage part 34.In addition, handling part 33B also performs the diagnostic process of the detection action for the alternating voltage V1 in voltage check device 1B, and whether normally the judged result of voltage check device 1B action is stored in storage part 34.Finally, handling part 33B performs output processing, makes the judged result etc. in the effective value of the alternating voltage V1 being stored in storage part 34 or amplitude and diagnostic process be shown in efferent 35.By like this, the detection of the alternating voltage V1 of the detected object 4 of voltage check device 1B is utilized to terminate.

Therefore; in this example; process is judged because handling part 33B also performs; therefore; the diagnosis (judgement) whether the result that operator can process according to this judgement and the detection action carrying out voltage in voltage check device 107 are normally carried out; wherein; judge that process is while detecting the level Va of signal content Ss2 of the relevant contrast signal Ss that Insulation monitoring signal S2 comprises; compare with specified level Vre, and judge that the action of voltage check device 107 is normal or abnormal process.Consequently, adopt this example, due to the alternating voltage V1 that operator can be made to distinguish detect be action normal time voltage or remarkable action time voltage, therefore, it is possible to improve the reliability for the alternating voltage V1 detected.

In addition, adopt the words of this example, due to can according in signal extraction portion 32 generate amplification detection signal S3, and detect by means of only utilizing the detection action of feedback control section 37 to be alternating voltage V1 of the high frequency band that cannot detect, therefore, it is possible to detect alternating voltage V1 non-contactly in wide frequency band range.In addition, in this example, owing to can detect output signal So as the signal of the impact of the coupling capacitance that can not be subject between detected object 4 and detecting electrode 12 (electrostatic capacitance C0), therefore, calculating of electrostatic capacitance C0 need not be carried out and also can detect alternating voltage V1 non-contactly.

In addition, in the voltage check device 107 that this example relates to, following formation can certainly be adopted, that is: in the same manner as the voltage check device 105 related to above-mentioned 5th example, as shown in phantom in Figure 17, handling part 33B is substituted in the level Va of the signal content Ss2 of the relevant contrast signal Ss that Insulation monitoring signal S2 that A point detects comprises, and be used in the level Va of the signal content of the relevant contrast signal Ss that amplification detection signal S3 that B point detects comprises, the level Va of the signal content of the relevant contrast signal Ss that the output signal So detected at C point comprises, or at the level Va of the relevant rectified signal Vd that D point detects, and perform the formation of diagnostic process, the diagnosis (judgement) whether the detection action can both carrying out voltage in voltage check device 1B according to any one level Va is normally carried out.

In addition, the voltage check device 105 that each example the 5th and the 6th relates to, in 106, have employed by by detecting electrode 12, power supply unit 13, test section 14 and insulation division 15 are contained in guard electrode 11, and with main body circuit portion 3, 3A does not form floating circuit portion 2 in consubstantiality ground, thus while raising CMRR (Common Mode Rejection Ratio), the formation of the detection of the alternating voltage V1 of high pressure can be carried out, but, when not needing to make test section 14 to carry out work with quick condition (such as, alternating voltage V1 is comparatively low pressure, or when not being required high CMRR), also can replace test section 14 and adopt the test section 14A shown in Fig. 5 (not use guard electrode 11, the test section of power supply unit 13 and insulation division 15).

In addition, adopting the voltage check device 105 of test section 14A, in 106, process is judged because handling part 33B also performs, therefore, the result that operator can process according to this judgement and carry out voltage check device 105, the diagnosis (judgement) that in 106, whether the detection action of voltage is normally carried out, wherein, while judging that process is the level Va (amplitude level of signal content Ss2) of the signal content Ss2 of the relevant contrast signal Ss that the detection signal S1 inputted detecting replacement Insulation monitoring signal S2 comprises, compare with specified level Vre, and judge voltage check device 105, the action of 106 is normal or abnormal process.Therefore, due to the voltage check device 105,106 by have employed this test section 14A, also can make operator distinguish the alternating voltage V1 detected be action normal time voltage or remarkable action time voltage, therefore, it is possible to improve for the reliability of the alternating voltage V1 detected.

In addition, in the voltage check device 1 that have employed this test section 14A, following formation can certainly be adopted, that is: in the same manner as the situation of the voltage check device 1 of above-mentioned employing test section 14, as shown in phantom in Figure 15, handling part 33B is substituted in the detection signal S1 that A point detects and (replaces in same figure from the Insulation monitoring signal S2 that insulation division 15 exports, and from the detection signal that the test section 14A of Fig. 5 exports) the level Va of the signal content Ss2 of relevant contrast signal Ss that comprises, and be used in the level Va of the signal content of the relevant contrast signal Ss that amplification detection signal S3 that B point detects comprises, or the level Va of the signal content of the relevant contrast signal Ss comprised at the output signal So that C point detects, or at the level Va of the relevant rectified signal Vd that D point detects, and perform the formation of diagnostic process, the diagnosis (judgement) whether the detection action can both carrying out voltage in voltage check device 1 according to any one level Va is normally carried out.

In addition, in the voltage check device 106 that have employed this test section 14A, following formation can certainly be adopted, that is: in the same manner as the above-mentioned situation that have employed the voltage check device 106 of test section 14, as shown in phantom in Figure 16, handling part 33B is substituted in the detection signal S1 that A point detects and (replaces in same figure from the Insulation monitoring signal S2 that insulation division 15 exports, and from the detection signal that the test section 14A of Fig. 5 exports) the level Va of the signal content Ss2 of relevant contrast signal Ss that comprises, and be used in the level Va of the signal content of the relevant contrast signal Ss that amplification detection signal S3 that B point detects comprises, or at the level Va of the relevant rectified signal Vd that D point detects, and perform the formation of diagnostic process, the diagnosis (judgement) whether the detection action can both carrying out voltage in voltage check device 106 according to any one level Va is normally carried out.

Claims

1. a voltage check device, it detects the detected object alternating current produced in detected object, and it is characterized in that, described voltage check device is provided with: detecting electrode, contrast signal efferent, test section and signal extraction portion;

Described detecting electrode is relative with described detected object and arranged and carry out capacitive coupling with this detected object;

Described contrast signal efferent exports contrast signal;

Described test section is connected to described detecting electrode, simultaneously, input described contrast signal and by according to detected object electric current with the detection signal of amplitude variations exports with reference to two current values of electric current, wherein, described detected object electric current is the electric current circulated according to detected object alternating voltage, and described is the electric current circulated according to described contrast signal with reference to electric current;

Described signal extraction portion, it is such that the amplitude of the signal content of the described contrast signal comprised with described detection signal becomes setting, and ride gain described detection signal is amplified, from the amplification detection signal that its result obtains, extract the signal content of described detected object alternating voltage, and export as output signal;

Described signal extraction portion has: become with described setting the control circuit that prespecified fixed value controls described gain like that, and extracted and the wave filter exported from described amplification detection signal by the signal content of described detected object alternating voltage.

2. a line voltage distribution pick-up unit, is characterized in that,

Be provided with: the multiple voltage check devices detecting the alternating voltage produced respectively in the multiple circuit as detected object, and

Calculate the differential voltage of the alternating voltage detected by described multiple voltage check device, thus obtain the calculating section of the line voltage distribution between described multiple circuit;

As described multiple voltage check device, use the voltage check device described in claim 1 respectively.