CN202721656U - After current phase demodulation circuit - Google Patents
After current phase demodulation circuit Download PDFInfo
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- CN202721656U CN202721656U CN 201220449007 CN201220449007U CN202721656U CN 202721656 U CN202721656 U CN 202721656U CN 201220449007 CN201220449007 CN 201220449007 CN 201220449007 U CN201220449007 U CN 201220449007U CN 202721656 U CN202721656 U CN 202721656U
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Abstract
The utility model provides an after current phase demodulation circuit, comprising a power supply voltage reference square wave generation circuit, an after current signal square wave generation circuit and a controller, wherein the power supply voltage reference square wave generation circuit comprises a first filtering circuit, an isolation voltage drop circuit and a first square wave generation circuit, the after current signal square wave generation circuit comprises an after current induction circuit, a signal state conversion circuit, a second filtering circuit, a signal primary amplification circuit, a signal secondary amplification circuit and a second square wave generation circuit, and the controller comprises an AD conversion unit, a timing unit and an interruption unit. The after current phase demodulation circuit employs two stages of amplification circuits, and can enable smaller after current signals to use a rear second channel and larger after current signals to use a first channel and the second channel, thereby greatly increasing sampling precision; and square wave comparison signals are generated from the second channel, and an after current generation phase can be accurately detected when the after current signals are small in intensity, thereby effectively avoiding the problems that in the prior art the larger and smaller after current detection accuracy can not considered simultaneously in the process of after current phase detection.
Description
Technical field
The utility model relates to a kind of three-phase residual current detection circuit, and specifically a kind of phase discriminator of residual current phase place belongs to the residual current detection technical field.
Background technology
Residual current circuit breaker is more and more wider in use in market; wherein simulate discrete and still occupy the mass market; the product that has can only carry out residual current protecting and not have the residual current display unit; although what have has a residual current display unit; but can only detect total residual current; do not occur in wherein which phase and can not accurately detect residual current; yet; residual current substantially all occurs in single-phase usually; when causing the large-area power-cuts maintenance in case residual current occurs; particularly in rural power grids, circuit is long, uses electrodispersion; and be distributed in the mountain area more; the maintainer need to be to A; B; the C three-phase is all investigated, and has greatly increased maintainer's workload, and efficient is relatively low.
Chinese patent literature CN101162834A discloses sound-deadening electricity-saving vector type electrical leakage testing method and earth leakage protective device, detects the vector of low-voltage distributing line Leaked Current of Line to Ground and is residual current by zero sequence current mutual inductor.The residual current of the prior art is after rectification is amplified, one the tunnel delivers to the size that interface microcontroller PC4 obtains leakage current, interface microcontroller PC0 is delivered to through phase detecting circuit in another road, utilize single-chip microcomputer to measure the poor of two adjacent AC signal and phase reference, thereby it is poor to obtain two adjacent phase of ac signal.Residual current after the method for detecting phases of the residual current of the prior art amplifies rectification only uses an operational amplifier to come detected phase, during this Design of Amplifiers, if design for little electric current, need to arrange larger multiplication factor, could satisfy the needs that little electric current amplifies, if but the electric current that detect this moment is large electric current, then the multiple of method is excessive; If arrange for large electric current, then can not satisfy the amplification demand of little electric current.That is to say that the arranging of operational amplifier in this circuit is difficult to take into account large electric current and little electric current.Because and the size of our unpredictable residual current in the reality, so the method for detecting phases of this residual current can't be taken into account the detection accuracy of large and small residual current.
The utility model content
Technical problem to be solved in the utility model is to take into account the detection accuracy of large and small residual current in the prior art to the phase-detection of residual current, thereby provides a kind of large and small leakage current can both carry out the circuit of phase-detection.
For solving the problems of the technologies described above, the utility model is achieved through the following technical solutions:
A kind of phase discriminator of residual current phase place comprises the reference square wave generative circuit of power supply voltage, signal square wave generative circuit and the controller of residual current, wherein
The reference square wave generative circuit of described power supply voltage comprises
The first filter circuit: its input termination alternating current, carry out exporting after the filtering to described alternating current;
Isolated buck circuit: be connected with the output of described the first filter circuit, described filtered supply voltage carried out step-down process;
The first square wave generative circuit: be connected with the output of described isolated buck circuit, convert the supply voltage after the described step-down to square-wave signal by sine wave signal, described square-wave signal is the reference square wave of power supply voltage;
The signal square wave generative circuit of described residual current comprises residual current sensor circuit, signal condition change-over circuit, the second filter circuit, the elementary amplifying circuit of signal, signal secondary amplification circuit and the second square wave generative circuit, wherein:
The residual current sensor circuit: its input is connected on the circuit to be measured, is used for the residual current of induction line;
The signal condition change-over circuit: the output of its input termination described residual current sensor circuit, export after the residual current signal is converted to voltage signal;
The second filter circuit: the output of the described signal condition change-over circuit of its input termination, carry out described voltage signal to export after the filtering;
The elementary amplifying circuit of signal: the voltage signal after the residual current signal conversion is raised reference voltage place at 0.5 times, make this voltage signal that complete sinusoidal waveform be arranged, the elementary amplifying circuit of described signal comprises two inputs and an output, the first input end of the elementary amplifying circuit of described signal connects the output of described the second filter circuit, the reference voltage that the second input termination of the elementary amplifying circuit of described signal is 0.5 times;
Signal secondary amplification circuit: the voltage signal after the elementary amplifying circuit amplification of described signal is amplified again, described signal secondary amplification circuit comprises two inputs and two outputs, the first input end of described signal secondary amplification circuit connects the output of the elementary amplifying circuit of described signal, the reference voltage that the second input termination of described signal secondary amplification circuit is 0.5 times;
The second square wave generative circuit: the voltage after will amplifying converts square-wave signal to by sine wave signal, described the second square wave generative circuit comprises two inputs and an output, the first input end of described the second square wave generative circuit connects the first output of described signal secondary amplification circuit, the reference voltage that the second input termination of described the second square wave generative circuit is 0.5 times, the output signal of described output is the signal square wave of described residual current;
Described controller comprises
AD converting unit: for detection of the size of residual current, comprise AD conversion mouth and the 2nd AD conversion mouth, described AD conversion mouth connects the output of the elementary amplifying circuit of described signal, and described the 2nd AD conversion mouth connects the second output of described signal secondary amplification circuit;
Interrupt location, comprise for the first fracture of the reference square wave that receives power supply voltage with for signal square wave the second fracture that receives residual current, fracture connects the output of described the first square wave generative circuit in described first, and fracture connects the output of described the second square wave generative circuit in described second;
Timing unit, record fracture in the reference square wave and described second that fracture in described first receives described power supply voltage and receive the rising edge of signal square wave of described residual current or the time difference of trailing edge, the phase difference that residual current lags behind the benchmark phase obtains by formula φ=2 π tl/Tl, Tl is power frequency period, start timing by the square wave after the reference signal shaping, square wave after the residual current signal shaping stops timing, is tl between institute's timing.
The phase discriminator of described residual current phase place, the signal square wave generative circuit of described residual current also comprises protective circuit, the described signal condition change-over circuit of the input termination of described protective circuit, described the second filter circuit of the output termination of described protective circuit.
The phase discriminator of described residual current phase place, described the first filter circuit comprises piezo-resistance U1, common mode inductance T1, capacitor C 1, alternating current connects the two ends of described piezo-resistance U1, two inputs of the described common mode inductance T1 of two terminations of described piezo-resistance U1, two outputs of described common mode inductance T1 and the input that jointly connects described isolated buck circuit after the two ends of described capacitor C 1 are connected.
The phase discriminator of described residual current phase place, described isolated buck circuit comprises two winding transformer S1.
The phase discriminator of described residual current phase place, described the first square wave generative circuit comprises resistance R 1, R2, R3, R4, capacitor C 2, diode D1, triode Q1, the output of described isolated buck circuit is connected with the base stage of described triode Q1 by resistance R 1, described capacitor C 2, diode D1, resistance R 2 in parallel rear one terminates at the link of described resistance R 1 and described triode Q1 base stage, ground connection after the other end is connected with the emitter of described triode Q1, the collector electrode of described triode Q1 connects an end of described resistance R 3, another termination DC power supply of described resistance R 3, one of described resistance R 4 terminates at the collector electrode of described triode Q1 and the link of described resistance R 3, the other end of described resistance R 4 and described controller first in fracture link to each other.
The phase discriminator of described residual current phase place, described residual current sensor circuit comprises zero sequence current mutual inductor.
The phase discriminator of described residual current phase place, described signal condition change-over circuit comprises resistance R 5.
The phase discriminator of described residual current phase place, described the second filter circuit comprises capacitor C 3, the two ends of described capacitor C 3 connect the first input end of the output of described signal condition change-over circuit, the elementary amplifying circuit of described signal simultaneously.
The phase discriminator of described residual current phase place, the elementary amplifying circuit of described signal comprises resistance R 6, R7, R8, R9, capacitor C 4, operational amplifier U1C, the first output of one termination, second filter circuit of described resistance R 6, the reverse input end of the described operational amplifier U1C of another termination, second output that connects the second filter circuit of described resistance R 7 one ends, the in the same way input of the described operational amplifier U1C of another termination, be connected described resistance R 8 between the output of described operational amplifier U1C and the reverse input end, described output connects described signal secondary amplification circuit first input end simultaneously, the one AD changes mouth, the link of the in the same way input of the described resistance R 7 of one termination of described capacitor C 4 and described operational amplifier U1C, the other end ground connection of described capacitor C 4, the link of the in the same way input of the described resistance R 7 of one termination of described resistance R 9 and described operational amplifier U1C, the reference voltage that another termination is 0.5 times.
The phase discriminator of described residual current phase place, described signal secondary amplification circuit comprises resistance R 10, R11, R12, R13, capacitor C 5, C6, operational amplifier U1D; The reverse input end of described operational amplifier U1D is connected by the output of described resistance R 10 with the elementary amplifying circuit of described signal, the in the same way input of described operational amplifier U1D connects 0.5 times reference voltage by described resistance R 11, be connected capacitor C 5 between the in the same way input of described operational amplifier U1D and the reverse input end, be connected by described resistance R 12 between the output of described operational amplifier U1D and the reverse input end, the output of described operational amplifier U1D is connected with the first input end of described the second square wave generative circuit, the output of described operational amplifier U1D is by described resistance R 13 and ground connection again after described capacitor C 6 is connected, described resistance R 13 and described capacitor C 6 be connected termination the 2nd AD conversion mouthful.
The phase discriminator of described residual current phase place, described the second square wave generative circuit comprises resistance R 14, R15, operational amplifier U1B; The in the same way input of described operational amplifier U1B is connected with the first output of described signal secondary amplification circuit by described resistance R 14, the reverse input end of described operational amplifier U1B connects 0.5 times reference voltage, and the output of described operational amplifier U1B connects fracture in described second by described resistance R 15.
The phase discriminator of described residual current phase place, described controller are single-chip microcomputer.
The phase discriminator of described residual current phase place; described protective circuit comprises diode D2, D3; ground connection after the negative pole of described diode D2 is connected with the positive pole of described diode D3; the positive pole of described diode D2 connects the negative pole of described diode D3, and jointly connects the output of described signal condition change-over circuit.
The phase discriminator of described residual current phase place, described reference voltage are the operating voltage of controller.
The phase discriminator of described residual current phase place, the operating voltage of single-chip microcomputer are 5V.
The phase discriminator of described residual current phase place, the operating voltage of single-chip microcomputer are 3.3V.
Technique scheme of the present utility model has the following advantages compared to existing technology:
(1) phase discriminator of residual current phase place described in the utility model, the reference square wave generative circuit that comprises power supply voltage, signal square wave generative circuit and the controller of residual current, the reference square wave generative circuit of this power supply voltage, comprise the first filter circuit, isolated buck circuit and the first square wave generative circuit, the signal square wave generative circuit of this residual current comprises the residual current sensor circuit, the signal condition change-over circuit, the second filter circuit, the elementary amplifying circuit of signal, signal secondary amplification circuit and the second square wave generative circuit, this controller comprises the AD converting unit, timing unit, interrupt location.The phase discriminator of above-mentioned residual current phase place has been used amplifying circuit twice, use the second channel of back in the time of can making little residual electricity signal, use first passage to add the mode of second channel during large residual electricity signal, greatly improved the precision of sampling, produce the square wave comparison signal from high channel, make it in the less situation of residual electricity signal, also can accurately measure the phase place that residual current occurs, effectively avoided to take into account the phase-detection of residual current in the prior art problem of the detection accuracy of large and small residual current.
(2) phase discriminator of residual current phase place described in the utility model; the signal square wave generative circuit of this residual current also comprises protective circuit; make the voltage of signal condition change-over circuit output in restricted portion, in order to avoid damage operational amplifier, guarantee the normal operation of circuit.
(3) phase discriminator of residual current phase place described in the utility model, a 0.5VREF(Voltage Reference is set, reference voltage) reference power supply is raised the residual electricity signal, makes it that complete sinusoidal waveform be arranged, and has improved real-time and the accuracy of residual current detection.
(4) phase discriminator of residual current phase place described in the utility model utilizes triode and operational amplifier to realize, and only has one road power supply, avoids using the two-way power supply, and circuit is oversimplified.
Description of drawings
For content of the present utility model is more likely to be clearly understood, below in conjunction with accompanying drawing, the utility model is described in further detail, wherein,
Fig. 1 is an example structure schematic diagram of the phase discriminator of residual current phase place described in the utility model;
Fig. 2 is the circuit theory diagrams of reference square wave generative circuit of power supply voltage of the phase discriminator of the described residual current phase place of Fig. 1;
Fig. 3 is the circuit theory diagrams of signal square wave generative circuit of residual current of the phase discriminator of the described residual current phase place of Fig. 1;
Fig. 4 is another example structure schematic diagram of the phase discriminator of residual current phase place described in the utility model;
Fig. 5 is the circuit theory diagrams of signal square wave generative circuit of residual current of the phase discriminator of the described residual current phase place of Fig. 4;
Fig. 6 is phase measurement each point waveform schematic diagram.
Reference numeral is expressed as among the figure: the reference square wave generative circuit of 1-power supply voltage; 11-the first filter circuit, 12-isolated buck circuit, 13-the first square wave generative circuit; the signal square wave generative circuit of 2-residual current; 21-residual current sensor circuit, 22-signal condition change-over circuit, 23-the second filter circuit; the elementary amplifying circuit of 24-signal; 25-signal secondary amplification circuit, 26-the second square wave generative circuit, 27-protective circuit; the 3-controller; the 31-AD converting unit, 311-the one AD changes mouth, and 312-the 2nd AD changes mouth; the 32-timing unit; the 33-interrupt location, fracture among the 331-first, fracture among the 332-second.
Embodiment
Embodiment 1:
The structure of the phase discriminator of residual current phase place described in the utility model as shown in Figure 1, it comprises the reference square wave generative circuit 1 of power supply voltage, signal square wave generative circuit 2 and the controller 3 of residual current.
The reference square wave generative circuit 1 of described power supply voltage comprises the first filter circuit 11, isolated buck circuit 12 and the first square wave generative circuit 13, and described the first filter circuit 11 input termination 220V alternating currents carry out exporting after the filtering to described alternating current; Referring to shown in Figure 2, in the present embodiment, described the first filter circuit 11 comprises piezo-resistance U1, common mode inductance T1, capacitor C 1, the 220V alternating current connects the two ends of described piezo-resistance U1, two inputs of the described common mode inductance T1 of two terminations of described piezo-resistance U1, two outputs of described common mode inductance T1 and the input that jointly connects described isolated buck circuit after the two ends of described capacitor C 1 are connected.Described isolated buck circuit 12 is connected with the output of described the first filter circuit, to described filtered supply voltage isolate, step-down processes; Referring to shown in Figure 2, in the present embodiment, described isolated buck circuit 12 comprises can further reduce the two winding transformer S1 that EMC disturbs, the elementary two ends that are connected on described capacitor C 1 of described two winding transformer S1, S1 level of described two winding transformer is as the input of the described first square wave generative circuit 13 of output termination of described isolated buck circuit 12.Described the first square wave generative circuit 13 is connected with the output of described isolated buck circuit 12, converts the supply voltage after the described step-down to square-wave signal by sine wave signal, and described square-wave signal is the reference square wave of power supply voltage.Referring to shown in Figure 2, in the present embodiment, described the first square wave generative circuit 13 comprises resistance R 1, R2, R3, R4, capacitor C 2, diode D1, triode Q1, end ground connection in the winding of S1 level of described two winding transformer, the other end is connected with the base stage of described triode Q1 by resistance R 1, described capacitor C 2, diode D1, resistance R 2 in parallel rear one terminates at the link of described resistance R 1 and described triode Q1 base stage, ground connection after the other end is connected with the emitter of described triode Q1, the collector electrode of described triode Q1 connects an end of described resistance R 3, another termination of described resistance R 3+5V DC power supply, one of described resistance R 4 terminates at the collector electrode of described triode Q1 and the link of described resistance R 3, the other end of described resistance R 4 and described controller 3 first in fracture 331 be that IRQ1 among Fig. 2 links to each other, export a square-wave signal.
The signal square wave generative circuit 2 of described residual current comprises residual current sensor circuit 21, signal condition change-over circuit 22, the second filter circuit 23, the elementary amplifying circuit 24 of signal, signal secondary amplification circuit 25 and the second square wave generative circuit 26.
Described residual current sensor circuit 21 inputs are connected on the circuit to be measured, are used for the residual current of induction line; Referring to shown in Figure 3, in the present embodiment, described residual current sensor circuit 21 comprises zero sequence current mutual inductor TA, in its input termination phase three-wire three circuit, and an end ground connection of secondary side.
As other execution modes, in the input termination three-phase and four-line circuit of described zero sequence current mutual inductor TA.
The output of the described residual current sensor circuit 21 of described signal condition change-over circuit 22 input terminations is exported after the residual current signal of described zero sequence current mutual inductor TA output is converted to voltage signal; Referring to shown in Figure 3, in the present embodiment, described signal condition change-over circuit 22 comprises resistance R 5, and two of described resistance R 5 terminates at the secondary side of described zero sequence current mutual inductor TA.
The output of the described signal condition change-over circuit 22 of described the second filter circuit 23 input terminations carries out described voltage signal to export after the filtering; Referring to shown in Figure 3, in the present embodiment, described the second filter circuit 23 comprises capacitor C 3, and the two ends of described capacitor C 3 connect the two ends of described resistance R 5 simultaneously.
Voltage signal after the elementary amplifying circuit 24 of described signal is changed the residual current signal is raised at the 0.5VREF place, makes this voltage signal that complete sinusoidal waveform be arranged; The elementary amplifying circuit 24 of described signal comprises two inputs and an output, and the first input end of the elementary amplifying circuit 24 of described signal connects the output of described the second filter circuit 23, the second input termination 0.5VREF of the elementary amplifying circuit 24 of described signal; Referring to shown in Figure 3, in the present embodiment, the elementary amplifying circuit 24 of described signal comprises resistance R 6, R7, R8, R9, capacitor C 4, operational amplifier U1C, one end of the described capacitor C 3 of one termination of described resistance R 6, the reverse input end of the described operational amplifier U1C of another termination, the other end that connects described capacitor C 3 of described resistance R 7 one ends, the in the same way input of the described operational amplifier U1C of described resistance R 7 another terminations, be connected described resistance R 8 between the output of described operational amplifier U1C and the reverse input end, described output connects described signal secondary amplification circuit 25 first input ends simultaneously, the one AD conversion mouth 311 of the AD converting unit 31 of controller 3, the link of the in the same way input of the described resistance R 7 of one termination of described capacitor C 4 and described operational amplifier U1C, the other end ground connection of described capacitor C 4, the link of the in the same way input of the described resistance R 7 of one termination of described resistance R 9 and described operational amplifier U1C, another termination 0.5VREF.
Voltage signal after the elementary amplifying circuit 24 of 25 pairs of described signals of described signal secondary amplification circuit amplifies amplifies again, described signal secondary amplification circuit 25 comprises two inputs and two outputs, the first input end of described signal secondary amplification circuit 25 connects the output of the elementary amplifying circuit 24 of described signal, the second input termination 0.5VREF of described signal secondary amplification circuit 25; Referring to shown in Figure 3, in the present embodiment, described signal secondary amplification circuit 25 comprises resistance R 10, R11, R12, R13, capacitor C 5, C6, operational amplifier U1D; The reverse input end of described operational amplifier U1D is connected with the output of described operational amplifier U1C by described resistance R 10, the in the same way input of described operational amplifier U1D meets 0.5VREF by described resistance R 11, be connected capacitor C 5 between the in the same way input of described operational amplifier U1D and the reverse input end, be connected by described resistance R 12 between the output of described operational amplifier U1D and the reverse input end, the output of described operational amplifier U1D is connected with the first input end of described the second square wave generative circuit 26, the output of described operational amplifier U1D is by described resistance R 13 and ground connection again after described capacitor C 6 is connected, the 2nd AD conversion of described resistance R 13 and the AD converting unit 31 that is connected termination controller 3 of described capacitor C 6 mouthfuls 312.
Voltage after described the second square wave generative circuit 26 will amplify converts square-wave signal to by sine wave signal, described the second square wave generative circuit 26 comprises two inputs and an output, the first input end of described the second square wave generative circuit 26 connects the first output of described signal secondary amplification circuit 25, the second input termination 0.5VREF of described the second square wave generative circuit 26, the output signal of described output is the signal square wave of described residual current; Referring to shown in Figure 3, in the present embodiment, described the second square wave generative circuit 26 comprises resistance R 14, R15, operational amplifier U1B; The in the same way input of described operational amplifier U1B is connected with described operational amplifier U1D output by described resistance R 14, the reverse input end of described operational amplifier U1B meets 0.5VREF, the output of described operational amplifier U1B connect by described resistance R 15 described controller 3 interrupt location 33 second in fracture 332, i.e. IRQ2 among Fig. 3.
The AD1 place links to each other with AD conversion mouthful the 311, the 2nd AD conversion mouth 312 of AD converting unit 31 respectively with the AD2 place, can gather and calculate the residual current signal.The AD1 place samples to the first passage residual current, the AD2 place samples to the second channel residual current, when single-chip microcomputer detects AD2 and is in undersaturated condition or saturation condition, be that voltage signal after the residual current conversion is between 0-2.5V the time, utilize the AD1 place that the first passage residual current is sampled, when single-chip microcomputer detects AD2 and is in state after saturated, be that voltage signal after the residual current conversion is during greater than 2.5V, utilize the AD1 place that the first passage residual current is sampled, simultaneously, utilize the AD2 place that the second channel residual current is sampled.
Residual current when AD2 is in undersaturated condition or saturation condition is little residual current, and the residual current that AD2 is in saturated rear state is large residual current.In the present embodiment, during little residual current signal, when namely the voltage signal after the residual current conversion is between 0-2.5V, use the AD2 place that the second channel leakage current is sampled; During large residual current signal, i.e. voltage signal after the residual current conversion uses AD1 place that the sampling of first passage residual current, AD2 place are sampled to the second channel residual current during greater than 2.5V simultaneously, and the two residual current addition is large residual current; Then fracture 332 is processed in second of the interrupt location 33 by single-chip microcomputer, can accurately judge that residual current is to occur in which phase place, makes things convenient for the staff to overhaul.
As other execution modes, controller is that operating voltage is the single-chip microcomputer of 3.3V, and described reference voltage is the operating voltage of controller, and 0.5VREF is 1.8V or 2V.
The phase discriminator of residual current phase place described in the utility model, two winding transformer S1 secondary side produces a reference square wave, the residual current square wave that detects with described zero sequence current mutual inductor TA forms relatively, process and calculate by single-chip microcomputer, calculate accurately residual current and occur in which phase place, make things convenient for the staff to overhaul fast.
With power supply phase (A phase) as the benchmark phase, convert power supply, residual current shaping to corresponding with it sine wave signal, square-wave signal, send into respectively single-chip microcomputer first in fracture 332 in the fracture 331 and second, utilize the timing unit 32 of single-chip microcomputer, time difference to the rising edge of two square-wave signals measures, and then through calculating, thereby the measurement of realization phase place.The each several part waveform of relevant phase measurement as shown in Figure 6.(a) figure is benchmark phase signals waveform among Fig. 6, (b) figure is square wave corresponding after the shaping of benchmark phase signals among Fig. 6, (c) figure is the residual current signal waveform among Fig. 6, and (d) figure is square wave corresponding after the residual current signal shaping among Fig. 6, and Tl is power frequency period 20ms.Start timing by the square wave after the shaping of benchmark phase signals, square wave after the residual current signal shaping stops timing, be tl between institute's timing, as shown in (c) figure, figure (d) among Fig. 6, tl has namely represented the phase difference that residual current lags behind the benchmark phase=2 π tl/Tl.
Embodiment 2:
On the basis of above-described embodiment 1; the signal square wave generative circuit 2 of described residual current also comprises protective circuit 27; referring to shown in Figure 4, the described signal condition change-over circuit 22 of the input termination of described protective circuit 27, described the second filter circuit 23 of the output termination of described protective circuit 27.Referring to shown in Figure 5; in the present embodiment; described protective circuit 27 comprises diode D2, D3; make the residual current of zero sequence current mutual inductor TA output through after the described resistance R 5; the voltage of output is no more than 0.7V, in order to avoid damage described operational amplifier U1C, and the negative pole of described diode D2 and the earth terminal that is connected on described resistance R 5 after the positive pole of described diode D3 is connected; the positive pole of described diode D2 connects the negative pole of described diode D3, and jointly connects the other end of described resistance R 5.
Obviously, above-described embodiment only is for example clearly is described, and is not the restriction to execution mode.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here need not also can't give all execution modes exhaustive.The apparent variation of being extended out thus or change still are among the protection range of the invention.
Claims (16)
1. the phase discriminator of a residual current phase place is characterized in that, comprises the reference square wave generative circuit of power supply voltage, signal square wave generative circuit and the controller of residual current, wherein
The reference square wave generative circuit of described power supply voltage comprises
The first filter circuit: its input termination alternating current, carry out exporting after the filtering to described alternating current;
Isolated buck circuit: be connected with the output of described the first filter circuit, described filtered supply voltage carried out step-down process;
The first square wave generative circuit: be connected with the output of described isolated buck circuit, convert the supply voltage after the described step-down to square-wave signal by sine wave signal, described square-wave signal is the reference square wave of power supply voltage;
The signal square wave generative circuit of described residual current comprises residual current sensor circuit, signal condition change-over circuit, the second filter circuit, the elementary amplifying circuit of signal, signal secondary amplification circuit and the second square wave generative circuit, wherein:
The residual current sensor circuit: its input is connected on the circuit to be measured, is used for the residual current of induction line;
The signal condition change-over circuit: the output of its input termination described residual current sensor circuit, export after the residual current signal is converted to voltage signal;
The second filter circuit: the output of the described signal condition change-over circuit of its input termination, carry out described voltage signal to export after the filtering;
The elementary amplifying circuit of signal: the voltage signal after the residual current signal conversion is raised reference voltage place at 0.5 times, make this voltage signal that complete sinusoidal waveform be arranged, the elementary amplifying circuit of described signal comprises two inputs and an output, the first input end of the elementary amplifying circuit of described signal connects the output of described the second filter circuit, the reference voltage that the second input termination of the elementary amplifying circuit of described signal is 0.5 times;
Signal secondary amplification circuit: the voltage signal after the elementary amplifying circuit amplification of described signal is amplified again, described signal secondary amplification circuit comprises two inputs and two outputs, the first input end of described signal secondary amplification circuit connects the output of the elementary amplifying circuit of described signal, the reference voltage that the second input termination of described signal secondary amplification circuit is 0.5 times;
The second square wave generative circuit: the voltage after will amplifying converts square-wave signal to by sine wave signal, described the second square wave generative circuit comprises two inputs and an output, the first input end of described the second square wave generative circuit connects the first output of described signal secondary amplification circuit, the reference voltage that the second input termination of described the second square wave generative circuit is 0.5 times, the output signal of described output is the signal square wave of described residual current;
Described controller comprises
AD converting unit: for detection of the size of residual current, comprise AD conversion mouth and the 2nd AD conversion mouth, described AD conversion mouth connects the output of the elementary amplifying circuit of described signal, and described the 2nd AD conversion mouth connects the second output of described signal secondary amplification circuit;
Interrupt location, comprise for the first fracture of the reference square wave that receives power supply voltage with for signal square wave the second fracture that receives residual current, fracture connects the output of described the first square wave generative circuit in described first, and fracture connects the output of described the second square wave generative circuit in described second;
Timing unit, record fracture in the reference square wave and described second that fracture in described first receives described power supply voltage and receive the rising edge of signal square wave of described residual current or the time difference of trailing edge, the phase difference that residual current lags behind the benchmark phase obtains by formula φ=2 π tl/Tl, Tl is power frequency period, start timing by the square wave after the reference signal shaping, square wave after the residual current signal shaping stops timing, is tl between institute's timing.
2. the phase discriminator of residual current phase place according to claim 1; it is characterized in that; the signal square wave generative circuit of described residual current also comprises protective circuit; the described signal condition change-over circuit of the input termination of described protective circuit, described the second filter circuit of the output termination of described protective circuit.
3. the phase discriminator of residual current phase place according to claim 1 and 2, it is characterized in that, described the first filter circuit comprises piezo-resistance U1, common mode inductance T1, capacitor C 1, alternating current connects the two ends of described piezo-resistance U1, two inputs of the described common mode inductance T1 of two terminations of described piezo-resistance U1, two outputs of described common mode inductance T1 and the input that jointly connects described isolated buck circuit after the two ends of described capacitor C 1 are connected.
4. the phase discriminator of residual current phase place according to claim 3 is characterized in that, described isolated buck circuit comprises two winding transformer S1.
5. the phase discriminator of residual current phase place according to claim 4, it is characterized in that, described the first square wave generative circuit comprises resistance R 1, R2, R3, R4, capacitor C 2, diode D1, triode Q1, the output of described isolated buck circuit is connected with the base stage of described triode Q1 by resistance R 1, described capacitor C 2, diode D1, resistance R 2 in parallel rear one terminates at the link of described resistance R 1 and described triode Q1 base stage, ground connection after the other end is connected with the emitter of described triode Q1, the collector electrode of described triode Q1 connects an end of described resistance R 3, another termination DC power supply of described resistance R 3, one of described resistance R 4 terminates at the collector electrode of described triode Q1 and the link of described resistance R 3, the other end of described resistance R 4 and described controller first in fracture link to each other.
6. the phase discriminator of residual current phase place according to claim 5 is characterized in that, described residual current sensor circuit comprises zero sequence current mutual inductor.
7. the phase discriminator of residual current phase place according to claim 6 is characterized in that, described signal condition change-over circuit comprises resistance R 5.
8. the phase discriminator of residual current phase place according to claim 7, it is characterized in that, described the second filter circuit comprises capacitor C 3, and the two ends of described capacitor C 3 connect the first input end of the output of described signal condition change-over circuit, the elementary amplifying circuit of described signal simultaneously.
9. the phase discriminator of residual current phase place according to claim 8, it is characterized in that, the elementary amplifying circuit of described signal comprises resistance R 6, R7, R8, R9, capacitor C 4, operational amplifier U1C, the first output of one termination, second filter circuit of described resistance R 6, the reverse input end of the described operational amplifier U1C of another termination, second output that connects the second filter circuit of described resistance R 7 one ends, the in the same way input of the described operational amplifier U1C of another termination, be connected described resistance R 8 between the output of described operational amplifier U1C and the reverse input end, described output connects described signal secondary amplification circuit first input end simultaneously, the one AD changes mouth, the link of the in the same way input of the described resistance R 7 of one termination of described capacitor C 4 and described operational amplifier U1C, the other end ground connection of described capacitor C 4, the link of the in the same way input of the described resistance R 7 of one termination of described resistance R 9 and described operational amplifier U1C, the reference voltage that another termination is 0.5 times.
10. the phase discriminator of residual current phase place according to claim 9 is characterized in that, described signal secondary amplification circuit comprises resistance R 10, R11, R12, R13, capacitor C 5, C6, operational amplifier U1D; The reverse input end of described operational amplifier U1D is connected by the output of described resistance R 10 with the elementary amplifying circuit of described signal, the in the same way input of described operational amplifier U1D connects 0.5 times reference voltage by described resistance R 11, be connected capacitor C 5 between the in the same way input of described operational amplifier U1D and the reverse input end, be connected by described resistance R 12 between the output of described operational amplifier U1D and the reverse input end, the output of described operational amplifier U1D is connected with the first input end of described the second square wave generative circuit, the output of described operational amplifier U1D is by described resistance R 13 and ground connection again after described capacitor C 6 is connected, described resistance R 13 and described capacitor C 6 be connected termination the 2nd AD conversion mouthful.
11. the phase discriminator of residual current phase place according to claim 10 is characterized in that, described the second square wave generative circuit comprises resistance R 14, R15, operational amplifier U1B; The in the same way input of described operational amplifier U1B is connected with the first output of described signal secondary amplification circuit by described resistance R 14, the reverse input end of described operational amplifier U1B connects 0.5 times reference voltage, and the output of described operational amplifier U1B connects fracture in described second by described resistance R 15.
12. the phase discriminator of residual current phase place according to claim 11 is characterized in that, described controller is single-chip microcomputer.
13. the phase discriminator of residual current phase place according to claim 12; it is characterized in that; described protective circuit comprises diode D2, D3; ground connection after the negative pole of described diode D2 is connected with the positive pole of described diode D3; the positive pole of described diode D2 connects the negative pole of described diode D3, and jointly connects the output of described signal condition change-over circuit.
14. the phase discriminator of residual current phase place according to claim 13 is characterized in that, described reference voltage is the operating voltage of controller.
15. according to claim 12 or the phase discriminator of 14 described residual current phase places, it is characterized in that the operating voltage of single-chip microcomputer is 5V.
16. according to claim 12 or the phase discriminator of 14 described residual current phase places, it is characterized in that the operating voltage of single-chip microcomputer is 3.3V.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220449007 CN202721656U (en) | 2012-09-05 | 2012-09-05 | After current phase demodulation circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201220449007 CN202721656U (en) | 2012-09-05 | 2012-09-05 | After current phase demodulation circuit |
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| Publication Number | Publication Date |
|---|---|
| CN202721656U true CN202721656U (en) | 2013-02-06 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 201220449007 Withdrawn - After Issue CN202721656U (en) | 2012-09-05 | 2012-09-05 | After current phase demodulation circuit |
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| CN (1) | CN202721656U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102830266A (en) * | 2012-09-05 | 2012-12-19 | 德力西电气有限公司 | Phase discriminating circuit of residual current phase |
| CN109061759A (en) * | 2018-11-08 | 2018-12-21 | 江苏师范大学 | A kind of acceleration of gravity measuring instrument based on freely falling body method |
| CN110658367A (en) * | 2019-09-24 | 2020-01-07 | 深圳供电局有限公司 | Residual current simulation generation device and residual current action protection system |
| CN110658369A (en) * | 2019-09-24 | 2020-01-07 | 深圳供电局有限公司 | Residual current simulation generation device and residual current action protection system |
| CN110687328A (en) * | 2019-09-24 | 2020-01-14 | 深圳供电局有限公司 | Residual current simulation generation device and residual current action protection system |
-
2012
- 2012-09-05 CN CN 201220449007 patent/CN202721656U/en not_active Withdrawn - After Issue
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102830266A (en) * | 2012-09-05 | 2012-12-19 | 德力西电气有限公司 | Phase discriminating circuit of residual current phase |
| CN102830266B (en) * | 2012-09-05 | 2014-09-24 | 德力西电气有限公司 | Phase discriminating circuit of residual current phase |
| CN109061759A (en) * | 2018-11-08 | 2018-12-21 | 江苏师范大学 | A kind of acceleration of gravity measuring instrument based on freely falling body method |
| CN110658367A (en) * | 2019-09-24 | 2020-01-07 | 深圳供电局有限公司 | Residual current simulation generation device and residual current action protection system |
| CN110658369A (en) * | 2019-09-24 | 2020-01-07 | 深圳供电局有限公司 | Residual current simulation generation device and residual current action protection system |
| CN110687328A (en) * | 2019-09-24 | 2020-01-14 | 深圳供电局有限公司 | Residual current simulation generation device and residual current action protection system |
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