CN103018503B - High-precision power frequency micro differential source - Google Patents
High-precision power frequency micro differential source Download PDFInfo
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- CN103018503B CN103018503B CN201210510706.3A CN201210510706A CN103018503B CN 103018503 B CN103018503 B CN 103018503B CN 201210510706 A CN201210510706 A CN 201210510706A CN 103018503 B CN103018503 B CN 103018503B
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Abstract
The invention relates to a high-precision power frequency micro differential source. According to the high-precision power frequency micro differential source, a watchdog, a synchronous dynamic random access memory (SDRAM) and a flash unit (FLASH) are respectively connected with a main control chip through a data bus, output of the main control chip is divided into two ways by a 16 bit digital-to-analogue conversion (DAC) unit, and one way passes through a first pre-amplifier and then directly outputs V3 and V4 to serve as starting signals of voltage circuits of UP and UX; the other way is subjected to digital isolation, passes through a second pre-amplifier and outputs V1 and V2 to serve as starting signals of current circuits of IP and IX; a voltage reference DAC unit (VREFDAC) provides reference voltage for the 16 bit DAC unit; and an RS232 communication unit is subjected to optoelectronic isolation to be connected with a main control chip Blackfin531. According to the high-precision power frequency micro differential source, a full-digital waveform fitting technology is used for outputting, the amplitude and the phase position of output waveforms can be independently controlled and adjusted through software, the output accuracy is high, the adjustment automation degree is high, and a standard loop and a difference value loop use a digital isolation mode so that output signals can be overlaid at will.
Description
Technical field
The present invention relates to a kind of high precision power frequency elementary errors source for the precision of traditional mutual-inductor tester is tested.
Background technology
In order to guarantee power system security economical operation, must monitor the ruuning situation of power equipment.But general measurement and protective device can not directly access high-pressure side one time; and the high voltage of primary system and large current signal need to be converted to low-voltage and the little current signal of being convenient to secondary device measurement, this transfer process mainly completes by electric power mutual-inductor.Conventionally we are to realize by detecting voltage, the electric current of electric power mutual-inductor secondary side to the metering of electric weight.The accuracy of electric power mutual-inductor directly affects the metering accuracy of secondary side.Therefore,, for electric power mutual-inductor, we need to detect its ratio error and phase error.According to national metrological verification regulations, calibration method is mainly differential technique, is mainly ratio error and the phase error of comparison standard mutual inductor and tested mutual inductor.Means of testing is to use mutual-inductor tester measuring error.So the accuracy of mutual-inductor tester, directly affects the verification result of mutual inductor.Therefore, in measurement Law detailed rules for the implementation, mutual-inductor tester is also put into the measurement instrument catalogue of accepting mandatory administration, must carry out periodic calibration to it.Calibrating mode for mutual-inductor tester, rules have clearly regulation, concrete methods of realizing is two curtage signals of the poor and phase differential of mutual-inductor tester calibrating installation output known amplitude, output in two pairs of measurement terminal of tested tester, difference between the output valve of the measurement result of tested tester and mutual-inductor tester calibrating installation, is its measuring error.
Existing calibrating installation is mainly realized by ratio power-type calibrating installation, and the calibrating installation of ratio power-type is mainly to be accessed by civil power, then by a resonance filter, then forms a road operating voltage U through a pressure regulation transducer
p, a road working current I
p; Difference signal U
xand I
xbe mainly to convert by sampling mutual inductor, that the primary side of sampling mutual inductor accesses is U
pand I
psignal, U
xwith I
xratio to regulate be the output that the tap of the secondary side by transform sampling mutual inductor realizes different proportion, the adjusting of phase place be mainly by connecting some electric capacity, inductance component carrys out phase shift adjustment.The output degree of regulation of the power frequency ratio power supply of this kind of method realization is lower, and regulating gets up is manually to realize by controlling a lot of rotating disk knobs, regulates more complicated, and automaticity is not high.
2000.05.03 Chinese patent has been announced Chinese utility model patent < < program controlled power source used in testing > > that notification number is CN2376629Y for approaching most the application's prior art, its principal claim is: a kind of program controlled power source used in testing, it is characterized in that: comprise and take control circuit that CPU is core and being controlled by control circuit, the frequency conversion wave generator circuit being formed by frequency synthesizer circuit and Waveform generating circuit, the address generator that wherein Waveform generating circuit is connected with input end successively by output terminal, wave memorizer, D/A change-over circuit and waveform signal modulate circuit form.
Summary of the invention
Technical matters to be solved by this invention, just be to provide a kind of high precision power frequency elementary errors source, output adopts all-digital waveform fitting technique, output accuracy is high, the amplitude of output waveform and phase place can regulate by software control separately, regulate automaticity high and simple, standard loop and difference loop adopt digital isolation method, and the signal of output can be superposeed arbitrarily.
Solve the problems of the technologies described above, the technical solution used in the present invention is:
A high precision power frequency elementary errors source, comprises signal generating module and power amplifier module, it is characterized in that:
Described signal generating module comprises main control chip Blackfin531, watchdog circuit (watchdog), synchronous DRAM (SDRAM), flash cell (FLASH), D/A conversion unit (16 DAC), with reference to D/A conversion unit (VREFDAC), photoisolator, RS232 communication unit, digital isolated location and first, second preposition amplification, also have power supply AC-DC module to provide working power to all chips of signal generating module inside, and DC-DC module provide communication power supply;
Described watchdog, SDRAM, FLASH are connected with main control chip Blackfin531 by data bus respectively,
The output of described main control chip Blackfin531 is divided into two-way output after 16BitDAC: V3 is directly exported on a road after the first preposition amplification, V4, and V1 is exported again in another road after numeral isolation after the second preposition amplification, V2, V1, V2 and V3, V4 is not altogether; V1 and V3 are the enabling signal of the voltage amplification module of described power amplifier module, and V2 and V4 are the enabling signal of the electric current amplification module of described power amplifier module;
Described preposition amplification composition and annexation are: the output of D/A conversion unit is input to the inverting input of amplifier UB through a resistance R Q1, the positive input end grounding of amplifier, between the inverting input and output terminal of amplifier UB, be parallel with arm resistance RQ2 and building-out capacitor CQ, RQ2 and RQ1 form amplifying circuit, doubly, CQ is for the phase shift of compensating circuit for the RQ2/RQ1 that final output V is input;
Described VREFDAC provides reference voltage to 16BitDAC;
Described RS232 communication unit is connected with main control chip Blackfin531 after photoelectricity isolation.
Described power amplifier module comprises voltage amplification module and electric current amplification module;
Described voltage amplification module comprises: the first difference transport and placing device, first to fourth resistance R 1/R2/R3/R4, the first capacitor C, the first power amplifier U1, the first amplifier U2 and the first transformer T1;
The output voltage V that is input as main control chip Blackfin531 1 of the first difference amplifier or V3, export the first resistance to;
The in-phase input end of the first power amplifier U1 is inputted the output of the first resistance;
Output, the other end ground connection of one termination the first power amplifier U1 of primary, transformer secondary output is final voltage output end;
The second resistance two ends are connected between the in-phase input end and transformer secondary output output terminal of the first power amplifier U1;
Between the inverting input of the first power amplifier U1 and output terminal, be parallel with the first capacitor C, the 3rd resistance R 3, and the output terminal of the first amplifier U2 and inverting input;
The in-phase input end of the first amplifier U2 and output terminal ground connection all after the 4th resistance R 4.
Described electric current amplification module comprises: the second difference amplifier, the 5th resistance R 10, the 6th resistance R 20, the 7th resistance R 30, the 8th resistance R 40, the 9th resistance R 50, the second capacitor C 1, the second power amplifier U10, the second amplifier U20, the 3rd amplifier U30, the second transformer T10 and zero magnetic flux mutual inductor T20
The input signal of the second difference amplifier be signal generating module main control chip Blackfin531 output voltage V 2 or V4, export the 5th resistance R 10 to;
The output of in-phase input end input the 5th resistance R 10 of the second power amplifier U10;
Output, the other end ground connection of the termination second power amplifier U10 that the second transformer T10 is elementary;
Between the inverting input of the second power amplifier U10 and output terminal, be parallel with the second capacitor C 1, the 7th resistance R 30, and the output terminal of the second amplifier U20 and inverting input;
The in-phase input end of the second amplifier U20 and output terminal ground connection all after the 8th resistance R 40;
The homophase of the 3rd amplifier U30 and inverting input be the two ends of connecting to neutral magnetic flux mutual inductor T20 primary coil respectively, one end of a termination second transformer T10 secondary coil of the secondary coil of zero magnetic flux mutual inductor T20;
The output terminal of the 3rd amplifier U30 connects the in-phase input end of the second power amplifier U10 after the 6th resistance R 20;
The two ends of the 9th resistance R 50 are connected on respectively between the output terminal and inverting input of the 3rd amplifier U30;
The final output current of the other end of the secondary coil of the other end of the second transformer T10 secondary coil and zero magnetic flux mutual inductor T20;
Voltage circuit U
pand U
xenabling signal be V1 and V3, current return I
pand I
xenabling signal be V2 and V4.
Main working process:
All signals are processed and waveform fitting part completes by main control chip Blackfin531 processor, watchdog is partly mainly used in preventing program fleet, SDRAM is partly for providing the exchanges data place of program operation process, by data bus and Blackfin531, interconnect, FLASH is partly for store data, interconnected by data bus and Blackfin531.
Blackfin531 matching waveform out partly becomes simulating signal by 16BitDAC, pass through again preposition amplifier section by analog signal output, VREF partly provides reference voltage for the DAC to 16BIT, Blackfin531 and upper computer software communication realize by RS232 serial ports, and communication part mainly sends (T by two signal wires of Blackfin531
x) and receive (R
x) complete, send and receive signal wire is realized the isolation with external signal by photoisolator, guarantees that internal circuit is not subject to externalities.
4 road voltage signals of signal generating module output, wherein V1 is normal voltage U
penabling signal, V3 is difference voltage U
xenabling signal, V2 is normalized current I
penabling signal, V4 is difference electric current I
xenabling signal.
Voltage amplification module principle block diagram as shown in Figure 2, main working process is: the signal V1 of signal generating module output or V3 are after difference amplifier, output signal is more level and smooth, degree of distortion is less, then amplifies through power amplifier U1, and enlargement factor is by arm resistance R1, R2 determines, what R1 and R2 selected is the precision resister of 1PPM, and to guarantee the stability of output, power amplifier outputting drive voltage transformer T1 is as final output.Because transformer is to present low-impedance state for direct current signal, but the output of nearly all power amplifier all can contain DC component, so here we adopt amplifier U2 and R3, C to form low-pass filter, eliminate the direct current component of power amplifier output, to guarantee that transformer is operated under normal condition.
Electric current amplification module theory diagram as shown in Figure 3, main working process is: the signal V2 of signal generating module output or V4 are after difference amplifier, output signal is more level and smooth, degree of distortion is less, by power amplifier U10, amplified, enlargement factor determines by arm resistance R10 and R20 again, and what R10 and R20 selected is precision resister, to guarantee the stability of output, power amplifier output driving current transformer T10 output.The output of current transformer samples through zero passage magnetic flux mutual inductor T20, electric current after sampling is done I/V conversion through the I/V transducer of amplifier U30 and precision resistance R50 composition again, the output of I/V conversion feedbacks by resistance R 20 again, and the mutual inductor that zero magnetic flux mutual inductor employing precision is 1PPM is herein to guarantee the long-time stability of system.Because transformer is to present low-impedance state for direct current signal, but the output of nearly all power amplifier all can contain DC component, so here we adopt amplifier U20, resistance R 30 and capacitor C 1 form low-pass filter, eliminate the direct current component of power amplifier output, to guarantee that transformer is operated under normal condition.
This high precision power frequency elementary errors source major function is the performance of test mutual-inductor tester, and concrete method of testing is: high precision power frequency elementary errors source output high precision standard signal U
por I
p, the output of mock standard mutual inductor secondary side, U
por I
pbe connected to the standard input end of tested tester; Then by the differential pressure signal U of known value
xor poor stream signal I
xbe superimposed upon signal U
por I
pupper, the amount after stack and standard signal U
por I
pratio difference Δ ε and phase difference φ be known quantity, the amount after stack is input to the tested input end of mutual-inductor tester; Compare the measured value of mutual-inductor tester and the value of Δ ε, Δ φ, obtain ratio error and the phase error of tested mutual-inductor tester.
Beneficial effect: this high precision power frequency elementary errors source adopts full-electronic stored program control system output two-way high precision standard signal, two-way high precision elementary errors signal, wherein elementary errors signal can be superimposed upon on standard signal, and the signal after combination is the signal of a known proportion or known angular deviation with respect to standard signal.
Accompanying drawing explanation
Fig. 1 is signal generating module theory diagram in high precision power frequency elementary errors of the present invention source;
Fig. 2 is the pre-amplification circuit figure of signal generating module in high precision power frequency elementary errors of the present invention source;
Fig. 3 is voltage amplification module principle block diagram in high precision power frequency elementary errors of the present invention source;
Fig. 4 is electric current amplification module theory diagram in high precision power frequency elementary errors of the present invention source.
Embodiment
Below in conjunction with the drawings and specific embodiments, the present invention is described in detail.
Referring to Fig. 1 to Fig. 4, high precision power frequency elementary errors of the present invention source, mainly comprise 2 functional modules, be signal generating module and power amplifier module, power amplifier module comprises again voltage amplification module and electric current amplification module, and the AC signal of signal generating module output is exported to user after amplifying through power amplifier module again and used.
Paper signal generating module once below, as shown in Figure 1, signal generating module mainly comprises main control chip Blackfin531, watchdog part, SDRAM part, FLASH part, the DAC part of 16, VREF part, photoelectricity isolated part, RS232 communication part, digital isolated part, preposition amplifier section.The final output of signal generating module 4 road phase and magnitudes are adjustable voltage signal V1 separately all, V2, V3, V4, V1 wherein, V2 by digital isolated part isolation after output, with V
3, V
4not altogether.Power supply AC-DC module, its effect is that all chips to signal generating module inside provide working power, DC-DC module provides communication power supply for signal plate.Main working process: all signals are processed and waveform fitting part completes by main control chip Blackfin531 processor, watchdog is partly mainly used in preventing program fleet, SDRAM is partly for providing the exchanges data place of program operation process, by data bus and Blackfin531, interconnect, FLASH is partly for store data, interconnected by data bus and Blackfin531.Blackfin531 matching waveform out partly becomes simulating signal by 16BitDAC, pass through again preposition amplifier section by analog signal output, VREF partly provides reference voltage for the DAC to 16BIT, Blackfin531 and upper computer software communication realize by RS232 serial ports, and communication part mainly sends (T by two signal wires of Blackfin531
x) and receive (R
x) complete, send and receive signal wire is realized the isolation with external signal by photoisolator, guarantees that internal circuit is not subject to externalities.The 4 road voltage signals that signal plate is partly exported, wherein V1 is normal voltage U
penabling signal, V3 is difference voltage U
xenabling signal, V2 is normalized current I
penabling signal, V4 is difference electric current I
xenabling signal.
Referring to Fig. 2, preposition amplification composition and annexation are: the output of D/A conversion unit is input to the inverting input of amplifier UB through a resistance R Q1, the positive input end grounding of amplifier, between the inverting input and output terminal of amplifier UB, be parallel with arm resistance RQ2 and building-out capacitor CQ, RQ2 and RQ1 form amplifying circuit, and doubly, CQ is for the phase shift of compensating circuit for the RQ2/RQ1 that final output V is input.
Voltage amplification module principle block diagram as shown in Figure 3, comprises difference amplifier, resistance, electric capacity, power amplifier U1, amplifier U2, transformer.Main working process is: the signal V1 of signal generating module output or V3 are after difference amplifier, output signal is more level and smooth, degree of distortion is less, through power amplifier U1, amplify again, enlargement factor is by arm resistance R1, and R2 determines, what R1 and R2 selected is the precision resister of 1PPM, to guarantee the stability of output, power amplifier outputting drive voltage transformer T1 is as final output.Because transformer is to present low-impedance state for direct current signal, but the output of nearly all power amplifier all can contain DC component, so here we adopt amplifier U2 and R3, C to form low-pass filter, eliminate the direct current component of power amplifier output, to guarantee that transformer is operated under normal condition.
Electric current amplification module theory diagram as shown in Figure 4, comprises difference amplifier, resistance R 10, resistance R 20, resistance R 30, resistance R 40, capacitor C 1, power amplifier U10, amplifier U20, amplifier U30, transformer T10 and zero magnetic flux mutual inductor T20.Main working process is: the signal V2 of signal generating module output or V4 are after difference amplifier, output signal is more level and smooth, degree of distortion is less, by power amplifier U10, amplified again, enlargement factor is determined by arm resistance R10 and R20, what R10 and R20 selected is precision resister, to guarantee the stability of output, and power amplifier output driving current transformer T10 output.The output of current transformer samples through zero passage magnetic flux mutual inductor T20, electric current after sampling is done I/V conversion through the I/V transducer of amplifier U30 and precision resistance R50 composition again, the output of I/V conversion feedbacks by resistance R 20 again, and the mutual inductor that zero magnetic flux mutual inductor employing precision is 1PPM is herein to guarantee the long-time stability of system.Because transformer is to present low-impedance state for direct current signal, but the output of nearly all power amplifier all can contain DC component, so here we adopt amplifier U20, resistance R 30 and capacitor C 1 form low-pass filter, eliminate the direct current component of power amplifier output, to guarantee that transformer is operated under normal condition.
Claims (1)
1. a high precision power frequency elementary errors source, comprises signal generating module and power amplifier module, it is characterized in that:
Described signal generating module comprises: main control chip, watchdog circuit, synchronous DRAM, flash cell, D/A conversion unit, with reference to D/A conversion unit, photoisolator, communication unit, digital isolated location and the first preposition amplification, the second preposition amplification, also have power supply AC-DC module to provide working power to all chips of signal generating module inside, and DC-DC module provide communication power supply;
Described watchdog circuit, synchronous DRAM, flash cell are connected with main control chip by data bus respectively;
The output of described main control chip is divided into two-way output after D/A conversion unit: V3 is directly exported on a road after the first preposition amplification, V4, and V1 is exported again in another road after numeral isolation after the second preposition amplification, V2, V1, V2 and V3, V4 is not altogether; Wherein, V1 and V3 are the enabling signal of the voltage amplification module of described power amplifier module, and V2 and V4 are the enabling signal of the electric current amplification module of described power amplifier module;
Described preposition amplification composition and annexation are: the output of D/A conversion unit is input to the inverting input of amplifier UB through a resistance R Q1, the positive input end grounding of amplifier, between the inverting input and output terminal of amplifier UB, be parallel with arm resistance RQ2 and building-out capacitor CQ, RQ2 and RQ1 form amplifying circuit, doubly, CQ is for the phase shift of compensating circuit for the RQ2/RQ1 that final output V is input;
Described reference D/A conversion unit provides reference voltage to D/A conversion unit;
Described communication unit is connected with main control chip after photoelectricity isolation.
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|---|---|---|---|
| CN201210510706.3A CN103018503B (en) | 2012-11-29 | 2012-11-29 | High-precision power frequency micro differential source |
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|---|---|---|---|
| CN201210510706.3A CN103018503B (en) | 2012-11-29 | 2012-11-29 | High-precision power frequency micro differential source |
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| CN103018503B true CN103018503B (en) | 2014-10-22 |
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|---|---|---|---|---|
| CN103760392B (en) * | 2014-01-22 | 2016-05-25 | 西安电子科技大学 | Adjusting corrected signal for DC-DC converter produces circuit |
| CN108254709B (en) * | 2018-01-18 | 2020-04-21 | 国网浙江省电力有限公司电力科学研究院 | Conversion device for digital electric energy test |
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| CN203025222U (en) * | 2012-11-29 | 2013-06-26 | 广东电网公司电力科学研究院 | High-precision power frequency micro-differential source |
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|---|---|---|---|---|
| JP3072880B2 (en) * | 1994-06-02 | 2000-08-07 | 株式会社アドバンテスト | Voltage generator for IC test |
| JP3163232B2 (en) * | 1995-04-14 | 2001-05-08 | 松下電工株式会社 | Reference voltage generation circuit |
| CN2376629Y (en) * | 1999-05-05 | 2000-05-03 | 山东艾诺仪器有限公司 | Program-controlled testing power supply |
| CN202330486U (en) * | 2011-12-15 | 2012-07-11 | 西安四方机电有限责任公司 | Novel path signal source for detecting power cables |
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| CN203025222U (en) * | 2012-11-29 | 2013-06-26 | 广东电网公司电力科学研究院 | High-precision power frequency micro-differential source |
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Address after: 510080 Dongfeng East Road, Dongfeng, Guangdong, Guangzhou, Zhejiang Province, No. 8 Patentee after: Electric Power Research Institute of Guangdong Power Grid Co.,Ltd. Address before: 510080, No. 8, Qi Gang, Dongfeng East Road, Guangzhou, Guangdong Patentee before: ELECTRIC POWER RESEARCH INSTITUTE OF GUANGDONG POWER GRID Corp. |