CN105652079A - Alternating-current sampling device - Google Patents
Alternating-current sampling device Download PDFInfo
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- CN105652079A CN105652079A CN201610111662.5A CN201610111662A CN105652079A CN 105652079 A CN105652079 A CN 105652079A CN 201610111662 A CN201610111662 A CN 201610111662A CN 105652079 A CN105652079 A CN 105652079A
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Abstract
The invention provides an alternating-current sampling device which comprises a sampling unit and a processor unit. The processor unit receives and processes current signals and voltage signals collected by the sampling unit. The sampling unit comprises a voltage sampling circuit and a current sampling circuit. The current sampling circuit comprises a current transformer, an electric signal processing circuit and a differential motion amplifying circuit which are connected in sequence. The electric signal processing circuit comprises a resistor R39, a resistor R40, a resistor R45, a capacitor C109 and a capacitor C113. One end of the resistor R40 is connected with one input end of the differential motion amplifying circuit through the resistor R39, and the other end of the resistor R40 is connected with the other input end of the differential motion amplifying circuit through the resistor R45. One end of the capacitor C109 is connected with one input end of the differential motion amplifying circuit, and the other end of the capacitor C109 is grounded. One end of the capacitor C113 is connected with the other input end of the differential motion amplifying circuit, and the other end of the capacitor C113 is grounded. The connecting position of the resistor R40 and the resistor R39 is connected with one output end of the current transformer, and the connecting position of the resistor R40 and the resistor R45 is connected with other output end of the current transformer.
Description
Technical field
The present invention relates to electrical signal Sampling techniques field, it is specifically related to a kind of ac sampling device.
Background technology
Electrical signal sampling is by all continuous print analog current signal or analog voltage signal in upper for the time, amplitude, in the effect of sampling pulse, converts the time upper discrete (having fixed intervals on the time) to but still continuous print discrete analog signal in amplitude.
In computer control device, often to be used electrical signal collection module, be used for being converted to analog electrical signal the numerary signal that microprocessor can identify. Signals collecting for big alternating-current such as three-phase electrical networks generally adopts mutual inductor that big current is converted to small area analysis, then by sampling conditioning circuit, the electrical signal gathered is carried out filter and amplification and processes so that sampled signal glitch-free, that amplitude is suitable is input to subsequent disposal device. But mutual inductor carrys out work by electromagnetic induction, it is easy to be subject to the interference of electromagnetic field, electromagnetism interference poor performance, therefore easily causes being input to the sampled signal accuracy in microprocessor low. Other common alternating current sampling circuits adopt series connection sampling resistance, sampling umformer, sampling integrator etc. in switching tube or inductance to sample, but also exist output signal unstable, disturb the problems such as big.
And if be input to sampled signal in subsequent conditioning circuit to there is interference, accuracy low, so follow-up metering, pilot circuit is inevitable also be affected. Therefore, the interference in maximum degree suppression sampled signal is technical problem urgently to be resolved hurrily.
Summary of the invention
Therefore, the technical problem to be solved in the present invention is to utilize in the electrical signal of mutual inductor collection and there is larger interference, and accuracy is low, and the impact of subsequent process circuit is big.
For this reason, following technical scheme is embodiments provided:
A kind of ac sampling device, comprising:
Sampling unit, gathers electric current signal and the voltage signal of each phase of three-phase electrical network;
Treater unit, receives the electric current signal of sampling unit collection and voltage signal is gone forward side by side row relax;
Power subsystem, for sampling unit, treater unit provide electric energy;
Wherein, sampling unit comprises voltage sampling circuit and current sampling circuit, and current sampling circuit comprises the current transformer, electric signal processing circuit and the differential amplify circuit that connect successively;
Electric signal processing circuit comprises resistance R39, R40, R45 and electric capacity C109, C113, one end of resistance R40 is connected with an input terminus of differential amplify circuit by resistance R39, the other end of resistance R40 is connected with another input terminus of differential amplify circuit by resistance R45, one end of electric capacity C109 is connected with an input terminus of differential amplify circuit, the other end ground connection, one end of electric capacity C113 is connected with another input terminus of differential amplify circuit, the other end ground connection, resistance R40 is connected with an output terminal of current transformer with the junction of resistance R39, resistance R40 is connected with another output terminal of current transformer with the junction of resistance R45, the output terminal of differential amplify circuit is connected with treater unit.
Preferably, resistance R41 also it is provided with between the output terminal of differential amplify circuit and treater unit.
Preferably, also comprising electric capacity C112, one end of electric capacity C112 is connected with the output terminal of differential amplify circuit, the other end is connected with the reference voltage input of differential amplify circuit.
Preferably, power subsystem comprises primary source circuit and sampling reference circuit, primary source circuit comprises the first process circuit that low dropout voltage regulator is connected and the 2nd process circuit being connected with low dropout voltage regulator output terminal with low dropout voltage regulator input terminus, first process circuit comprises the first filtering circuit, and the 2nd process circuit comprises the first voltage stabilizing circuit; Sampling reference circuit comprises the 3rd process circuit that bandgap voltage reference chip is connected and the 4th process circuit being connected with bandgap voltage reference chip output with bandgap voltage reference chip input terminus, 3rd process circuit comprises the 2nd filtering circuit, and the 4th process circuit comprises the 2nd voltage stabilizing circuit.
Preferably:
Primary source circuit is connected with the power input of differential amplify circuit, for powering for differential amplify circuit;
Sampling reference circuit is connected with the reference voltage input of differential amplify circuit, for providing stable votage reference for differential amplify circuit.
Preferably, also comprising electric capacity C106, C107, one end of electric capacity C106 is connected with the power input of differential amplify circuit, the other end ground connection, and electric capacity C107 is in parallel with electric capacity C106.
Preferably, first filtering circuit comprises inductance B3, electric capacity C77 and C75, the first end of inductance B3 connects external source, the 2nd end is connected with the input terminus of low dropout voltage regulator, the first end of electric capacity C77 and the first end of electric capacity C75 are connected with the 2nd end of inductance B3 respectively, the 2nd end of electric capacity C77 and the 2nd common ground connection of end of electric capacity C75.
Preferably, first voltage stabilizing circuit comprises diode D1 and electric capacity C78, C76, the negative electrode of diode D1 is connected with the output terminal of low dropout voltage regulator, plus earth, the first end of electric capacity C78, the first end of electric capacity C76 are connected with the output terminal of low dropout voltage regulator respectively, 2nd end of electric capacity C78, the 2nd common ground connection of end of electric capacity C76, the junction of the first end of electric capacity C78 and the first end of electric capacity C76 is as the output terminal of primary source circuit.
Preferably, 2nd filtering circuit comprises electric capacity C85, C86, the first end of electric capacity C85, the first end of electric capacity C86 respectively input terminus with bandgap voltage reference chip be connected, 2nd end of electric capacity C85, the 2nd common ground connection of end of electric capacity C86, the input terminus of bandgap voltage reference chip connects the output terminal of primary source circuit.
Preferably, 2nd voltage stabilizing circuit comprises diode D3 and electric capacity C88, C89, the first end of electric capacity C88, the first end of electric capacity C89 respectively output terminal with bandgap voltage reference chip be connected, 2nd end of electric capacity C88, the 2nd common ground connection of end of electric capacity C89, the negative electrode of diode D3 is connected with the output terminal of bandgap voltage reference chip, the plus earth of diode D3.
Technical solution of the present invention, tool has the following advantages:
1. the ac sampling device that the embodiment of the present invention provides, its electric signal processing circuit and differential amplify circuit form current sampling signal conditioning circuit, its effect is: sampled signal carries out filtering process to eliminate interference wherein, and carry out the calibration on hardware, become the signal within the level scope that the microprocessor in treater unit can identify by sampled signal. Wherein, resistance R45 and electric capacity C113 forms a resistance-capacitance absorption network, and resistance R39 and electric capacity C109 forms another resistance-capacitance absorption network. The electric current that current transformer exports inputs the common mode anti-interference protective circuit formed by above-mentioned two resistance-capacitance absorption networks after resistance R40 samples and limits width. Wherein, the electric current signal that current transformer 11 is exported by the circuit that resistance R39, R40 and R45 forms is converted to voltage signal. Resistance-capacitance absorption network effectively suppression can operate moment vibration and the high-frequency current of superpotential, and the waveform of superpotential is slowed down, and steepness and amplitude reduce, and add the damping action of resistance, HF oscillation is decayed rapidly, play the effect of stable output voltage. In addition, the resistance of resistance R39 is preferably equal with the resistance of resistance R45, to ensure good common mode inhibition. Thus improve the accuracy of the sampled signal being input to treater unit.
2. the ac sampling device that the embodiment of the present invention provides, its differential amplify circuit adopts high speed and precision differentiating amplifier INA143, + IN the pin of high speed and precision differentiating amplifier and-IN pin two input terminuss respectively as differential amplify circuit, OUTPUT pin is as the output terminal of differential amplify circuit. Resistor network is placed on amplifier inside by this high speed and precision differentiating amplifier, mated by laser trimming resistor network, make differentiating amplifier common-mode rejection ratio can reach more than 80dB, there is higher efficiency of conversion, lower gain error, not only further suppress the interference in sampled signal, and improve the corresponding speed of sampling circuit.
Accompanying drawing explanation
In order to be illustrated more clearly in the specific embodiment of the invention or technical scheme of the prior art, it is briefly described to the accompanying drawing used required in embodiment or description of the prior art below, apparently, accompanying drawing in the following describes is some embodiments of the present invention, for those of ordinary skill in the art, under the prerequisite not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the structure block diagram of a kind of ac sampling device in the embodiment of the present invention;
Fig. 2 is the schematic circuit of current sampling circuit in the embodiment of the present invention;
Fig. 3 is the structure block diagram of power subsystem in Fig. 1;
Fig. 4 is the schematic circuit of the primary source circuit in Fig. 1;
Fig. 5 is the schematic circuit of sampling reference circuit in Fig. 1;
Fig. 6 is the electricity of a kind of ac sampling device in the embodiment of the present invention (not comprising power subsystem)
Line structure schematic diagram.
Embodiment
Below in conjunction with accompanying drawing, the technical scheme of the present invention is clearly and completely described, it is clear that described embodiment is the present invention's part embodiment, instead of whole embodiments. Based on the embodiment in the present invention, those of ordinary skill in the art, not making other embodiments all obtained under creative work prerequisite, belong to the scope of protection of the invention.
In describing the invention, it should be noted that, it is based on orientation shown in the drawings or position relation that the orientation of the instruction such as term " " center ", " on ", D score, "left", "right", " vertically ", " level ", " interior ", " outward " or position are closed; be only the present invention for convenience of description and simplified characterization; instead of the device that refers to of instruction or hint or element must have specific orientation, with specific orientation structure and operation, therefore can not be interpreted as limitation of the present invention. In addition, term " first ", " the 2nd ", " the 3rd " are only for describing object, and can not be interpreted as instruction or hint relative importance.
In describing the invention, it is necessary to explanation, unless otherwise clearly defined and limited, term " installation ", " being connected ", " connection " should be interpreted broadly, such as, it is possible to be fixedly connected with, it is also possible to be removably connect, or connect integratedly; Can be mechanically connected, it is also possible to be electrical connection; Can be directly be connected, it is also possible to be indirectly connected by intermediary, it is also possible to be the connection of two element internals, it is possible to be wireless connections, it is also possible to be wired connection. For the ordinary skill in the art, it is possible to particular case understands above-mentioned term concrete implication in the present invention.
In addition, if below in the described different enforcement mode of the present invention involved technology feature do not form conflict each other and just can be combined with each other.
Embodiment 1
As shown in Figure 1, originally execute example and provide a kind of ac sampling device, comprising:
Sampling unit 1, gathers electric current signal and the voltage signal of each phase of three-phase electrical network;
Treater unit 2, receives electric current signal that sampling unit 1 gathers and voltage signal is gone forward side by side row relax;
Power subsystem 3, for sampling unit 1, treater unit 2 provide electric energy;
Wherein, sampling unit 1 comprises voltage sampling circuit and current sampling circuit, and current sampling circuit comprises the current transformer 11, electric signal processing circuit 12 and the differential amplify circuit 13 that connect successively;
Electric signal processing circuit 12 comprises resistance R39, R40, R45 and electric capacity C109, C113, one end of resistance R40 is connected with an input terminus of differential amplify circuit 13 by resistance R39, the other end of resistance R40 is connected with another input terminus of differential amplify circuit 13 by resistance R45, one end of electric capacity C109 is connected with an input terminus of differential amplify circuit 13, the other end ground connection, one end of electric capacity C113 is connected with another input terminus of differential amplify circuit 13, the other end ground connection, resistance R40 is connected with an output terminal of current transformer 11 with the junction of resistance R39, resistance R40 is connected with another output terminal of current transformer 11 with the junction of resistance R45, the output terminal of differential amplify circuit 13 is connected with treater unit 2.
In the present embodiment, electric signal processing circuit 12 and differential amplify circuit 13 form current sampling signal conditioning circuit, its effect is: sampled signal carries out filtering process to eliminate interference wherein, and carry out the calibration on hardware, become the signal within the level scope that the microprocessor in treater unit can identify by sampled signal. Wherein, resistance R45 and electric capacity C113 forms a resistance-capacitance absorption network, and resistance R39 and electric capacity C109 forms another resistance-capacitance absorption network. The electric current that current transformer 11 exports inputs the common mode anti-interference protective circuit formed by above-mentioned two resistance-capacitance absorption networks after resistance R40 samples and limits width. Wherein, the electric current signal that current transformer 11 is exported by the circuit that resistance R39, R40 and R45 forms is converted to voltage signal. Resistance-capacitance absorption network effectively suppression can operate moment vibration and the high-frequency current of superpotential, and the waveform of superpotential is slowed down, and steepness and amplitude reduce, and add the damping action of resistance, HF oscillation is decayed rapidly, play the effect of stable output voltage. In addition, the resistance of resistance R39 is preferably equal with the resistance of resistance R45, to ensure good common mode inhibition. Thus improve the accuracy of the sampled signal being input to treater unit.
In addition, differential amplify circuit 13 in the present embodiment adopts high speed and precision differentiating amplifier INA143 (i.e. U17 in Fig. 2), + IN the pin of high speed and precision differentiating amplifier U17 and-IN pin two input terminuss respectively as differential amplify circuit 13, OUTPUT pin is as the output terminal of differential amplify circuit 13. Resistor network is placed on amplifier inside by this high speed and precision differentiating amplifier U17, mated by laser trimming resistor network, make differentiating amplifier common-mode rejection ratio can reach more than 80dB, there is higher efficiency of conversion, lower gain error, not only further suppress the interference in sampled signal, and improve the corresponding speed of sampling circuit. This high speed and precision differentiating amplifier U17 has two kinds of operating voltage patterns: two power supply, and operating voltage is at positive and negative 2.25V to positive and negative 18V; Single power supply, voltage is at positive 4.5V to positive 36V. The rapid precipitation time: 9 �� sto0.01%; Efficiency of conversion: 5V/ �� s; Quiescent current: 950 �� A; Gain: G=10V/V or G=0.1V/V; Benefit error: 0.01%.
In the present embodiment, this sampling apparatus treater adopts the dsp chip TMS320C6747 of TI. This device is by the UART1 serial ports access upper computer of dsp chip, it is achieved with the communication of upper computer. Dsp chip TMS320C6747 is double-core low power processor, dominant frequency can reach 300MHz, 2,400 hundred ten thousand fixed point instructions within every second, can be performed, 1,800 hundred ten thousand floating-point instructions within every second, can be performed, it is possible to realize the real-time process of sampling data and complete corresponding Industry Control according to result. This device is mainly used in the mass data to sampling unit 1 gathers and has carried out real-time computing, when for the collection of power quality analysis data, specifically complete the electric current to A, B, C three-phase, voltage acquisition, and the computing of wattful power, wattless power and power quality index.
As concrete enforcement mode, the voltage sampling circuit in above-mentioned sampling unit 1 is for gathering the voltage signal of main power circuit, and current sampling circuit is for gathering the electric current signal of main power circuit. Voltage sampling circuit specifically comprises voltage sample conditioning circuit. In addition, that the AD conversion chip in the present embodiment adopts is the ADS8365 of TI, and this chip is the modulus conversion chip that a kind of high speed, low-power consumption, 6 passage synchronized samplings and conversion, list+5V power. Change maximum sampling through-put rate and up to 5MHz, and passage and 6 difference sampling retainers can be inputted with the fully differential of the common mode inhibition of 80dB. Pin inner portions is also with votage reference and the high speed parallel port of 2.5V. Therefore adopt the ADS8365 of TI, the precision of this A/D chip and passage number, meet this device completely to the sampling request of the electric current of three-phase electricity and voltage. As shown in Figure 6, ADS8365 is connected by the 8Bit parallel port of EMIFA and dsp chip, the voltage of six passages difference sampling three-phase electricity of ADS8365 and electric current, being converted to numerary signal, by high speed parallel port, signal is inputted dsp chip, the computing through dsp chip can obtain the data such as the electric current of A, B, C three-phase, voltage, wattful power, wattless power and power quality index.
As concrete enforcement mode, as shown in Figure 2, resistance R41 also it is provided with between the output terminal of differential amplify circuit 13 and treater unit 2. Specifically, one end of resistance R41 respectively OUTPUT pin and SENSE pin with high speed and precision differentiating amplifier U17 (INA143) be connected, the other end is connected with the Signal reception pin of the dsp chip in treater unit 2 by A/D converter circuit. This resistance R41 is as sampling resistance, and according to Ohm's law, the voltage signal exported by differential amplify circuit 13 is again converted to electric current signal and is input to treater unit 2.
As preferred embodiment, also comprise electric capacity C112, as shown in Figure 2, one end of electric capacity C112 is connected (being specifically connected) with the junction of resistance R41 and treater unit 2 with the output terminal of differential amplify circuit 13, the other end is connected with the reference voltage input (i.e. the REF pin of high speed and precision differentiating amplifier U17) of differential amplify circuit 13. This electric capacity C112 is as electric capacity of voltage regulation, and when the voltage that differential amplify circuit 13 exports changes, electric capacity both end voltage can not instantaneous change, so that output voltage relative smooth. In other embodiment, the electric signal processing circuit 12 of this ac sampling device also comprises electric capacity C111, its two ends respectively with two input terminuss of differential amplify circuit 13, namely two input terminuss (+IN and-IN) of high speed and precision differentiating amplifier U17 connect. Electric capacity C111 is as bypass electric capacity, it is possible to further filtering interfering, stablize sampled signal.
As further preferred embodiment, this ac sampling device also comprises electric capacity C106, C107, one end of electric capacity C106 is connected with the power input (i.e. the V+ pin of high speed and precision differentiating amplifier U17) of differential amplify circuit 13, the other end ground connection, and electric capacity C107 is in parallel with electric capacity C106. This electric capacity C106, C107 are decoupling capacitance, form filtering voltage regulation loop. Decoupling capacitance C106, C107 are parallel between the positive and negative electrode of power supply, can prevent the positive feedback path that circuit is formed by power supply and the spurious oscillation caused. That is, the high frequency interference of the fluctuation and input circuit of eliminating power supply, on the impact of chip (high speed and precision differentiating amplifier U17), serves the effect of stable output voltage.
As concrete enforcement mode, as shown in Figure 3, power subsystem 3 comprises primary source circuit 31 and sampling reference circuit 32, primary source circuit 31 comprises the first process circuit 311 that low dropout voltage regulator 312 is connected and the 2nd process circuit 313 being connected with low dropout voltage regulator 312 output terminal with low dropout voltage regulator 312 input terminus, first process circuit 311 comprises the first filtering circuit, and the 2nd process circuit 313 comprises the first voltage stabilizing circuit; Sampling reference circuit 32 comprises the 3rd process circuit 321 that bandgap voltage reference chip 322 is connected and the 4th process circuit 323 being connected with bandgap voltage reference chip 322 output terminal with bandgap voltage reference chip 322 input terminus, 3rd process circuit 321 comprises the 2nd filtering circuit, and the 4th process circuit 323 comprises the 2nd voltage stabilizing circuit.
The ac sampling device that the present embodiment provides, primary source circuit 31 adopts the low dropout voltage regulator 312 (TPS73250DBVR) (i.e. U12 in Fig. 4) of 5V, can still stable in no-output electric capacity situation export, load transient response performance is good, reverse leakage current is low, and noise is low. Solve owing to direct supply module exists noise, indirectly cause the problem of output voltage instability. The input terminus of low dropout voltage regulator 312 is provided with the first filtering circuit, for external input power carrying out filtering process to eliminate alternating component wherein, it is to increase the stability of input voltage. The output terminal of low dropout voltage regulator 312 is provided with the first voltage stabilizing circuit, improves the stability of primary source circuit 31 output voltage further. Stable power supply is also an important guarantee of the sampled signal accuracy of ac sampling device.
The sampling apparatus that the present embodiment provides, its sampling reference circuit 32 adopts the superhigh precision bandgap voltage reference AD780BR (i.e. U14 in Fig. 5) of 2.5V, there is high precision, lower noise, low initial error, low quiescent current (being less than 1mA), the advantages such as wide input (4V-36V), low temperature drift (lower than 3ppm/ DEG C) and output voltage are stable, solve and indirectly cause the problem of output voltage instability owing to direct supply module exists noise and float the problem causing greatly output voltage instability due to the temperature of electronic component. The input terminus of bandgap voltage reference chip 322 (i.e. U14 in Fig. 5) is provided with the 2nd filtering circuit, for external input power being carried out the alternating component of filtering process to eliminate in input power, improve the stability of input voltage, solve the technical problem causing sampling reference circuit 32 output voltage instability owing to input voltage is unstable. The output terminal of bandgap voltage reference chip 322 (i.e. U14 in Fig. 5) is provided with the 2nd voltage stabilizing circuit, improves the stability of sampling reference circuit 32 output voltage further. The votage reference that nursing one's health circuit for ac sampling signal provides stable is also an important guarantee of ac sampling device sampled signal accuracy.
Above-mentioned sampling apparatus can be used for the collection of power quality analysis data, namely electric current and the voltage signal of each phase in three-phase alternating current electrical network is gathered in real time, then according to IEC61000-4-30 criterion calculation power quality index, electric energy adds up with carrying out, and also carries out quality of power supply transient state and transient affair judgement simultaneously. First sampling unit carries out 10 cycle data and calculates, and then calculates 3 number of seconds certificates by 10 cycle data. The effect of sampling apparatus is exactly carry out the calculating of power quality indexes and electric energy adds up, and ensures the reliability of accuracy and the metering measured.
Specifically:
Above-mentioned primary source circuit 31 is connected with the power input of differential amplify circuit 13, and namely V+ pin with high speed and precision differentiating amplifier U17 is connected, for powering for differential amplify circuit 13;
Sampling reference circuit 32 is connected with the reference voltage input of differential amplify circuit 13, and namely REF pin with high speed and precision differentiating amplifier U17 is connected, for providing stable votage reference for differential amplify circuit 13.
As preferred embodiment, as shown in Figure 4, first filtering circuit comprises inductance B3, electric capacity C77 and C75, the first end of inductance B3 connects external source, the 2nd end is connected with the input terminus of low dropout voltage regulator 312 (i.e. U12 in Fig. 4), the first end of electric capacity C77 and the first end of electric capacity C75 are connected with the 2nd end of inductance B3 respectively, the 2nd end of electric capacity C77 and the 2nd common ground connection of end of electric capacity C75. This first filtering circuit uses the inductance B3 of series connection, electric capacity C77 and C75 in parallel, before low dropout voltage regulator 312, input power is carried out filtering process, eliminates alternating component wherein.
As preferred embodiment, as shown in Figure 4, first voltage stabilizing circuit comprises diode D1 and electric capacity C78, C76, the negative electrode of diode D1 is connected with the output terminal of low dropout voltage regulator 312 (i.e. U12 in Fig. 4), plus earth, the first end of electric capacity C78, the first end of electric capacity C76 respectively output terminal with low dropout voltage regulator 312 be connected, 2nd end of electric capacity C78, the 2nd common ground connection of end of electric capacity C76, the junction of the first end of electric capacity C78 and the first end of electric capacity C76 is as the output terminal of primary source circuit 31. Diode D1 is Zener diode; can ensure to keep output voltage substantially constant when primary source circuit 31 outward current in very large range changes; diode D1 as electrostatic protection device, can also carry out noise processed and self protection after low dropout voltage regulator 312 output voltage in addition. Electric capacity C78, C76 in parallel can improve the stability of primary source circuit 31 output voltage further.
Specifically, above-mentioned primary source circuit 31 also comprises electric capacity C82, one end of electric capacity C82 is connected with the NR/FB pin of low dropout voltage regulator 312 (TPS73250DBVR) (i.e. U12 in Fig. 2), the other end ground connection, and this electric capacity C82 can the noise that produces of the inner band gap of filtering.
In other implementations, above-mentioned 2nd process circuit 313 also comprises inductance B4, and the first end of inductance B4 is connected with the junction of the first end of electric capacity C78 and the first end of electric capacity C76, and the 2nd end of inductance B4 is as the output terminal of primary source circuit 31.
In addition, in order to indicate the working order of this primary source circuit 31 in real time, this primary source circuit 31 also comprises LED 3, and the anode of LED 3 is connected with the 2nd end of inductance B4 by current limliting resistance R28, plus earth.
As preferred embodiment, as shown in Figure 5,2nd filtering circuit comprises electric capacity C85, C86, the first end of electric capacity C85, the first end of electric capacity C86 respectively input terminus with bandgap voltage reference chip 322 (i.e. U14 in Fig. 5) be connected, 2nd end of electric capacity C85, the 2nd common ground connection of end of electric capacity C86, the input terminus of bandgap voltage reference chip 322 connects the output terminal of primary source circuit 31. Before 2nd filtering circuit is arranged on bandgap voltage reference chip 322, it may also be useful to input power is carried out the alternating component of filtering process to eliminate in input power by electric capacity C85, C86 in parallel.
In addition, the 3rd process circuit 321 also comprises the electric capacity C87 falling for voltage stabilizing and making an uproar, and its one end is connected with the TEMP pin of bandgap voltage reference chip 322 (i.e. U14 in Fig. 5), the other end ground connection.
As preferred embodiment, as shown in Figure 5,2nd voltage stabilizing circuit comprises diode D3 and electric capacity C88, C89, the first end of electric capacity C88, the first end of electric capacity C89 respectively output terminal with bandgap voltage reference chip 322 (i.e. U14 in Fig. 5) be connected, 2nd end of electric capacity C88, the 2nd common ground connection of end of electric capacity C89, the negative electrode of diode D3 is connected with the output terminal of bandgap voltage reference chip 322 (i.e. U14 in Fig. 5), the plus earth of diode D3. Wherein, diode D3 is Zener diode, it is ensured that the stability of output voltage when the outward current of sampling reference circuit 32 in very large range changes. In addition, diode D3 is also electrostatic protection device, carries out noise processed and self protection after bandgap voltage reference chip 322 output voltage. Electric capacity C88, C89 in parallel can improve the stability of sampling reference circuit 32 output voltage further.
In other embodiment, this ac sampling device also comprises storage unit, and sampling data, program data and startup optimization data that receiving processor unit 2 sends also store. Specifically, as shown in Figure 6, storage unit comprises ferroelectric memory, synchronous dynamic random storer and can erasable nonvolatile memory (NORFLASH), data when ferroelectric memory is used for store sample data and falls electricity, synchronous dynamic random storer is used for storage system service data, can erasable nonvolatile memory (NORFLASH) for the startup data of storage of processor unit 2 and program data.
Above-mentioned ferroelectric memory adopts ferroelectric FM25V10RAM chip, is connected with dsp chip by SPI serial ports. Ferroelectric memory is by together with the advantages such as the unlimited read-write of the non-volatile storage character of ROM and RAM, high speed and low-power consumption. This device adopts ferroelectric memory FM25V10 based on spi bus technology, and spi bus has at a high speed and reliable advantage. It is applicable to deposit mass data that sampling obtains and needs the data that store when device falls electricity.
Synchronous dynamic random storer (i.e. SDRAM) adopts MT48LC16M16A2TG chip, is connected by the parallel port of the 16Bit of EMIFB and dsp chip. This device due to the current and voltage data amount gathered big, the store content therefore required in system cloud gray model is big, and the SDRAM of high-speed high capacity can meet this device to the requirement of handling up of mass data, is the internal memory that dsp chip is rely and run.
8Bit can be connected by the high speed parallel port of the 8Bit of EMIFA and dsp chip by erasable nonvolatile memory (NORFLASH).
As preferred embodiment, this device also comprises the automatic reset circuit with function for monitoring, and automatic reset circuit is connected with treater unit 2. DSP6747 process chip needs system to provide the reset pulse of a 100-200ms to reset at the Shi Weiqi that powers on, owing to may occur to disturb and disturbed phenomenon when the operating frequency of DSP6747 process chip reaches more than 300MHz, cause system in case of system halt, so needing to be equipped with the automatic reset circuit with function for monitoring to play the effect of dog of guarding the gate. The present embodiment adopts the MAX706 reset chip of Maxim company production, and this chip has reliability and the immunity from interference that peripheral circuit is simple, can effectively improve this device.
In addition, the sampling apparatus that the present embodiment provides also comprises the crystal oscillator of the 24M that the CLKIN interface with dsp chip is connected.
Obviously, above-described embodiment is only for example is clearly described, and not to the restriction of the mode of enforcement. For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description. Here without the need to also cannot all enforcement modes be given exhaustive. And the apparent change thus extended out or variation are still among the protection domain of the invention.
Claims (10)
1. an ac sampling device, it is characterised in that, comprising:
Sampling unit (1), gathers electric current signal and the voltage signal of each phase of three-phase electrical network;
Treater unit (2), receives electric current signal that described sampling unit (1) gathers and voltage signal is gone forward side by side row relax;
Power subsystem (3), for described sampling unit (1), described treater unit (2) provide electric energy;
Wherein, described sampling unit (1) comprises voltage sampling circuit and current sampling circuit, and described current sampling circuit comprises the current transformer (11), electric signal processing circuit (12) and the differential amplify circuit (13) that connect successively;
Described electric signal processing circuit (12) comprises resistance R39, R40, R45 and electric capacity C109, C113, one end of described resistance R40 is connected with an input terminus of described differential amplify circuit (13) by resistance R39, the other end of described resistance R40 is connected with another input terminus of described differential amplify circuit (13) by resistance R45, one end of described electric capacity C109 is connected with an input terminus of described differential amplify circuit (13), the other end ground connection, one end of described electric capacity C113 is connected with another input terminus of described differential amplify circuit (13), the other end ground connection, described resistance R40 is connected with an output terminal of described current transformer (11) with the junction of described resistance R39, described resistance R40 is connected with another output terminal of described current transformer (11) with the junction of described resistance R45, the output terminal of described differential amplify circuit (13) is connected with described treater unit (2).
2. ac sampling device as claimed in claim 1, it is characterised in that, also it is provided with resistance R41 between the output terminal of described differential amplify circuit (13) and described treater unit (2).
3. ac sampling device as claimed in claim 1 or 2, it is characterized in that, also comprising electric capacity C112, one end of described electric capacity C112 is connected with the output terminal of described differential amplify circuit (13), the other end is connected with the reference voltage input of described differential amplify circuit (13).
4. ac sampling device as according to any one of claim 1-3, it is characterized in that, described power subsystem (3) comprises primary source circuit (31) and sampling reference circuit (32), described primary source circuit (31) comprises low dropout voltage regulator (312), the first process circuit (311) being connected with described low dropout voltage regulator (312) input terminus and the 2nd process circuit (313) being connected with described low dropout voltage regulator (312) output terminal, described first process circuit (311) comprises the first filtering circuit, described 2nd process circuit (313) comprises the first voltage stabilizing circuit, described sampling reference circuit (32) comprises the 3rd process circuit (321) that bandgap voltage reference chip (322) is connected and the 4th process circuit (323) being connected with described bandgap voltage reference chip (322) output terminal with described bandgap voltage reference chip (322) input terminus, described 3rd process circuit (321) comprises the 2nd filtering circuit, and described 4th process circuit (323) comprises the 2nd voltage stabilizing circuit.
5. ac sampling device as according to any one of claim 1-4, it is characterised in that:
Described primary source circuit (31) is connected with the power input of described differential amplify circuit (13), for being the power supply of described differential amplify circuit (13);
Described sampling reference circuit (32) is connected with the reference voltage input of described differential amplify circuit (13), for providing stable votage reference for described differential amplify circuit (13).
6. ac sampling device as according to any one of claim 1-5, it is characterized in that, also comprise electric capacity C106, C107, one end of described electric capacity C106 is connected with the power input of described differential amplify circuit (13), the other end ground connection, and described electric capacity C107 is in parallel with described electric capacity C106.
7. ac sampling device as according to any one of claim 1-6, it is characterized in that, described first filtering circuit comprises inductance B3, electric capacity C77 and C75, the first end of described inductance B3 connects external source, the 2nd end is connected with the input terminus of described low dropout voltage regulator (312), the first end of described electric capacity C77 and the first end of described electric capacity C75 are connected with the 2nd end of described inductance B3 respectively, the 2nd end of described electric capacity C77 and the 2nd common ground connection of end of described electric capacity C75.
8. ac sampling device as according to any one of claim 1-7, it is characterized in that, described first voltage stabilizing circuit comprises diode D1 and electric capacity C78, C76, the negative electrode of described diode D1 is connected with the output terminal of described low dropout voltage regulator (312), plus earth, the first end of described electric capacity C78, the first end of described electric capacity C76 respectively output terminal with described low dropout voltage regulator (312) be connected, 2nd end of described electric capacity C78, the 2nd common ground connection of end of described electric capacity C76, the junction of the first end of described electric capacity C78 and the first end of described electric capacity C76 is as the output terminal of described primary source circuit (31).
9. ac sampling device as according to any one of claim 1-8, it is characterized in that, described 2nd filtering circuit comprises electric capacity C85, C86, the first end of described electric capacity C85, the first end of described electric capacity C86 respectively input terminus with described bandgap voltage reference chip (322) be connected, the 2nd common ground connection of end of the 2nd end of described electric capacity C85, described electric capacity C86, the input terminus of described bandgap voltage reference chip (322) connects the output terminal of described primary source circuit (31).
10. ac sampling device as claimed in any one of claims 1-9 wherein, it is characterized in that, described 2nd voltage stabilizing circuit comprises diode D3 and electric capacity C88, C89, the first end of described electric capacity C88, the first end of described electric capacity C89 respectively output terminal with described bandgap voltage reference chip (322) be connected, the 2nd common ground connection of end of the 2nd end of described electric capacity C88, described electric capacity C89, the negative electrode of described diode D3 is connected with the output terminal of described bandgap voltage reference chip (322), the plus earth of described diode D3.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610111662.5A CN105652079A (en) | 2016-02-29 | 2016-02-29 | Alternating-current sampling device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201610111662.5A CN105652079A (en) | 2016-02-29 | 2016-02-29 | Alternating-current sampling device |
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| CN105652079A true CN105652079A (en) | 2016-06-08 |
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| CN201610111662.5A Pending CN105652079A (en) | 2016-02-29 | 2016-02-29 | Alternating-current sampling device |
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Application publication date: 20160608 |