CN103698638A - D/A (Digital-to-Analog) conversion circuit unit for relay protection experiment instrument - Google Patents
D/A (Digital-to-Analog) conversion circuit unit for relay protection experiment instrument Download PDFInfo
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- CN103698638A CN103698638A CN201310737053.7A CN201310737053A CN103698638A CN 103698638 A CN103698638 A CN 103698638A CN 201310737053 A CN201310737053 A CN 201310737053A CN 103698638 A CN103698638 A CN 103698638A
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Abstract
The invention relates to a D/A (Digital-to-Analog) conversion circuit unit for a relay protection experiment instrument. A relay protection device uses a self-coupling regulator, a high-current generator, a phase shifter and a slide rheostat to achieve the goal of check through amplitude, frequency and phase conversion of three-phase voltage and three-phase current. The D/A conversion circuit unit for the relay protection experiment instrument plays a very important role in the entire experiment instrument and the accuracy of the D/A conversion circuit unit directly influences the signal output accuracy of the relay protection experiment instrument. However, the signal output accuracy of the relay protection instrument which uses a wood comb for converting power is low and the experiment effect is affected. The D/A conversion circuit unit for the relay protection experiment instrument comprises a microprocessor (1). The microprocessor is connected with a group of high-speed optical couplers (2), the high-speed optical couplers (2) are connected with the a D/A conversion chip (3), the D/A conversion chip (3) is connected with a voltage conversion circuit (4), the voltage conversion circuit (4) is connected with a low-pass filter circuit (5) and the low-pass filter circuit (5) is connected with a power amplifier circuit (6). The D/A conversion circuit unit is used for the relay protection experiment instrument.
Description
technical field:
the present invention relates to a kind of D/A converting circuit unit for relay protection experimental instrument.
background technology:
phase early 1970s, the measuring technology of China's electric system is also in the stage of utilizing analog proving installation.Protective relaying device utilizes autocoupling type pressure regulator, current lifting device, phase shifter and slide rheostat by the amplitude-frequency phase tranformation to three-phase voltage and three-phase current, reaches the object of verification.Whole test process is worked in coordination and is made for completing the verification to relay equipment by precision instrumentation.Due to this method of testing, to exist proving installation heavier, be difficult to carry, and field adjustable task burdensome, the shortcoming such as wiring is complicated, and test accuracy is not high, stops using now substantially.D/A converting circuit unit for relay protection experimental instrument is very important in whole experiment instrument effect,the precision of D/A converting circuit unit directly affects
the signal output accuracy of relay protection experimental instrument, but use at present the signal output accuracy of wooden comb conversion electric power low, affect experiment effect.
summary of the invention:
the object of this invention is to provide a kind of D/A converting circuit unit for relay protection experimental instrument.
above-mentioned object realizes by following technical scheme:
a kind of D/A converting circuit unit for relay protection experimental instrument; its composition comprises: microprocessor; described microprocessor is connected with one group of High-Speed Coupled Device, described High-Speed Coupled Device is connected with D/A conversion chip; described D/A conversion chip is connected with voltage conversion circuit, described voltage conversion circuit is connected with low-pass filter circuit, and described low-pass filter circuit is connected with power amplifier.
the described D/A converting circuit unit for relay protection experimental instrument, described D/A conversion chip adopts MAX542 chip; Described MAX542 chip has 14 pins, and wherein in analog, pin 12 accesses digitally in pin 3,4 accesses; Pin 14 connects external power source, the power supply reference voltage of access+5V; At pin 5,6 end inputs, the reference voltage of external+5V; Pin 2 is output as bipolar voltage signal output part, need between pin 1 and pin 13, amplify by external high-operational amplifier to signal, and the while is reinforcing band load capacity also; Pin 10 is serial data input port; The chip selection signal that pin 7 is chip, when its low level, in running order; Pin 8 accesses, for the pulse of serial data displacement, are selected the frequency of operation of 6MHz; Pin 11 is D/A conversion transmission data input pin, when the rising edge of chip selection signal, what LDAC output pulse declined exports along input register data being carried out to D/A conversion, and be loaded into shift register process in 16 bit serial data, to keep high level always, after D/A conversion, adopt bipolarity output.
the described D/A converting circuit unit for relay protection experimental instrument; described power amplification circuit comprises voltage power amplifying unit, current power amplifying unit; described voltage power amplifying unit comprises prime input circuit, intermediate amplifying circuit, three grades of circuit of output dilatation; the described power amplification circuit RC circuit of connecting between pin 7,8; selecting capacitor C 21 is that 20pF, resistance R 17 are 330 Ω; in order to guarantee circuit steady operation, between pin 1,2, connect current-limiting resistance R18.
the described D/A converting circuit unit for relay protection experimental instrument, described current power amplifying unit comprises input circuit, amplifying circuit and feedback circuit, 1 pin of described current power amplifying unit, 2 pins, 3 pins, 4 pins, 9 pins, 10 pins, 11 pins, 5 pins, 7 pins, 6 pins connect respectively output terminal, output terminal, reverse input end, positive input,, positive supply V+ end, positive supply V+ end, negative supply V-end, negative supply V-end and current-limiting resistance, the external current-limiting resistance of 8 pin, is chosen as 10K herein; The output terminal of described current power amplifying unit is connected with R39 and R40 respectively, to after two output terminal IOUT parallel connection, meet pull-up resistor R42, meanwhile, the input end using load output terminal as differential amplifier, feed back to the initial input end of whole circuit, realize negative feedback function.
beneficial effect:
1. D/A conversion chip of the present invention is selected MAX542 chip.It has advantages of high precision, slewing rate is fast, reliability is high, serial transmission mode.
2. the present invention affects transformation result for reducing high-frequency interferencing signal, and the high-frequency signal that the signal after D/A conversion adulterated before ingoing power amplifying unit need to carry out low-pass filtering removing and process [26].The design adopt for the active filter of Butter-worth be low-pass filter, 1 rank LPF of the 1st grade of employing, that the 2nd grade and 3rd level adopt is all 2 rank LPF, three grades of low-pass filters that are combined into 5 rank, 2nd, 3 grades is all the filtering circuit that adopts multiple feedback, and this circuit can effectively be removed high-frequency signal.
3. power amplification circuit of the present invention unit is the important component part of relay protection experimental instrument.Consider the reason of reliability, security and stability; relay protection experimental instrument power amplifier chip in power amplification unit circuit design is selected respectively PA85 and OPA549; above two kinds of chips are all linear; not only meet the technical requirement of voltage and current output; chip has self-protection function, has strengthened the stability of circuit
4. the output terminal of current power amplifier of the present invention is connected with R39 and R40 respectively, to after two output terminal IOUT parallel connection, meet pull-up resistor R42, meanwhile, the input end using load output terminal as differential amplifier, feed back to the initial input end of whole circuit, realize negative feedback function.
5. circuit oscillation of the present invention and signal harmonic restrict the levels of precision of whole circuit, therefore need to correctly choose leading phase compensation C37 and compensation C30.Due to when power is exaggerated, voltage also will amplify thereupon, and impact output, therefore adopts the method for attachment of voltage follower to build power operational amplifier circuit, in the situation that not changing output voltage, by power amplification.
accompanying drawing explanation:
accompanying drawing 1 is structural representation of the present invention.
accompanying drawing 2 is circuit theory diagrams of D/A conversion chip in accompanying drawing 1.
accompanying drawing 3 is circuit theory diagrams of low-pass filter circuit in accompanying drawing 1.
accompanying drawing 4 is circuit theory diagrams of voltage power amplifying circuit in accompanying drawing 1.
accompanying drawing 5 is circuit theory diagrams of current power amplifying circuit in accompanying drawing 1.
embodiment:
embodiment 1:
a kind of D/A converting circuit unit for relay protection experimental instrument; its composition comprises: microprocessor 1; described microprocessor is connected with one group of High-Speed Coupled Device 2, described High-Speed Coupled Device is connected with D/A conversion chip 3; described D/A conversion chip is connected with voltage conversion circuit 4, described voltage conversion circuit is connected with low-pass filter circuit 5, and described low-pass filter circuit is connected with power amplifier 6.
embodiment 2:
according to the D/A converting circuit unit for relay protection experimental instrument described in embodiment 1, described D/A conversion chip adopts MAX542 chip; Described MAX542 chip has 14 pins, and wherein in analog, pin 12 accesses digitally in pin 3,4 accesses; Pin 14 connects external power source, the power supply reference voltage of access+5V; At pin 5,6 end inputs, the reference voltage of external+5V; Pin 2 is output as bipolar voltage signal output part, need between pin 1 and pin 13, amplify by external high-operational amplifier to signal, and the while is reinforcing band load capacity also; Pin 10 is serial data input port; The chip selection signal that pin 7 is chip, when its low level, in running order; Pin 8 accesses, for the pulse of serial data displacement, are selected the frequency of operation of 6MHz; Pin 11 is D/A conversion transmission data input pin, when the rising edge of chip selection signal, what LDAC output pulse declined exports along input register data being carried out to D/A conversion, and be loaded into shift register process in 16 bit serial data, to keep high level always, after D/A conversion, adopt bipolarity output.
embodiment 3:
according to the D/A converting circuit unit for relay protection experimental instrument described in embodiment 1 or 2; described power amplification circuit comprises voltage power amplifying unit, current power amplifying unit; described voltage power amplifying unit comprises prime input circuit, intermediate amplifying circuit, three grades of circuit of output dilatation; the described power amplification circuit RC circuit of connecting between pin 7,8; selecting capacitor C 21 is that 20pF, resistance R 17 are 330 Ω; in order to guarantee circuit steady operation, between pin 1,2, connect current-limiting resistance R18.
embodiment 4:
according to the D/A converting circuit unit for relay protection experimental instrument described in embodiment 1 or 2, described current power amplifying unit comprises input circuit, amplifying circuit and feedback circuit, 1 pin of described current power amplifying unit, 2 pins, 3 pins, 4 pins, 9 pins, 10 pins, 11 pins, 5 pins, 7 pins, 6 pins connect respectively output terminal, output terminal, reverse input end, positive input, ground, positive supply V+ end, positive supply V+ end, negative supply V-end, negative supply V-end and current-limiting resistance, the external current-limiting resistance of 8 pin, be chosen as 10K herein, the output terminal of described current power amplifying unit is connected with R39 and R40 respectively, to after two output terminal IOUT parallel connection, meet pull-up resistor R42, meanwhile, the input end using load output terminal as differential amplifier, feed back to the initial input end of whole circuit, realize negative feedback function.
Claims (4)
1. the D/A converting circuit unit for relay protection experimental instrument; its composition comprises: microprocessor; it is characterized in that: described microprocessor is connected with one group of High-Speed Coupled Device, described High-Speed Coupled Device is connected with D/A conversion chip; described D/A conversion chip is connected with voltage conversion circuit, described voltage conversion circuit is connected with low-pass filter circuit, and described low-pass filter circuit is connected with power amplifier.
2. the D/A converting circuit unit for relay protection experimental instrument according to claim 1, is characterized in that: described D/A conversion chip adopts MAX542 chip; Described MAX542 chip has 14 pins, and wherein in analog, pin 12 accesses digitally in pin 3,4 accesses; Pin 14 connects external power source, the power supply reference voltage of access+5V; At pin 5,6 end inputs, the reference voltage of external+5V; Pin 2 is output as bipolar voltage signal output part, need between pin 1 and pin 13, amplify by external high-operational amplifier to signal, and the while is reinforcing band load capacity also; Pin 10 is serial data;
Input port; The chip selection signal that pin 7 is chip, when its low level, in running order; Pin 8 accesses, for the pulse of serial data displacement, are selected the frequency of operation of 6MHz; Pin 11 is D/A conversion transmission data input pin, when the rising edge of chip selection signal, what LDAC output pulse declined exports along input register data being carried out to D/A conversion, and be loaded into shift register process in 16 bit serial data, to keep high level always, after D/A conversion, adopt bipolarity output.
3. the D/A converting circuit unit for relay protection experimental instrument according to claim 1 and 2; it is characterized in that: described power amplification circuit comprises voltage power amplifying unit, current power amplifying unit; described voltage power amplifying unit comprises prime input circuit, intermediate amplifying circuit, three grades of circuit of output dilatation; the described power amplification circuit RC circuit of connecting between pin 7,8; selecting capacitor C 21 is that 20pF, resistance R 17 are 330 Ω; in order to guarantee circuit steady operation, between pin 1,2, connect current-limiting resistance R18.
4. the D/A converting circuit unit for relay protection experimental instrument according to claim 1 and 2, it is characterized in that: described current power amplifying unit comprises input circuit, amplifying circuit and feedback circuit, 1 pin of described current power amplifying unit, 2 pins, 3 pins, 4 pins, 9 pins, 10 pins, 11 pins, 5 pins, 7 pins, 6 pins connect respectively output terminal, output terminal, reverse input end, positive input, ground, positive supply V+ end, positive supply V+ end, negative supply V-end, negative supply V-end and current-limiting resistance, the external current-limiting resistance of 8 pin, be chosen as 10K herein, the output terminal of described current power amplifying unit is connected with R39 and R40 respectively, to after two output terminal IOUT parallel connection, meet pull-up resistor R42, meanwhile, the input end using load output terminal as differential amplifier, feed back to the initial input end of whole circuit, realize negative feedback function.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310737053.7A CN103698638A (en) | 2013-12-27 | 2013-12-27 | D/A (Digital-to-Analog) conversion circuit unit for relay protection experiment instrument |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310737053.7A CN103698638A (en) | 2013-12-27 | 2013-12-27 | D/A (Digital-to-Analog) conversion circuit unit for relay protection experiment instrument |
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| CN103698638A true CN103698638A (en) | 2014-04-02 |
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| CN201310737053.7A Withdrawn CN103698638A (en) | 2013-12-27 | 2013-12-27 | D/A (Digital-to-Analog) conversion circuit unit for relay protection experiment instrument |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104539254A (en) * | 2014-12-30 | 2015-04-22 | 苏州优谱德精密仪器科技有限公司 | Signal filtering module |
| CN105827247A (en) * | 2016-03-21 | 2016-08-03 | 成都天进仪器有限公司 | Small signal output circuit for intelligent relay protection tester |
| CN112187277A (en) * | 2020-10-09 | 2021-01-05 | 中国船舶重工集团公司第七0七研究所九江分部 | Analog-digital signal conversion circuit with built-in test function |
| CN114233845A (en) * | 2021-11-12 | 2022-03-25 | 中国北方车辆研究所 | Wheeled chariot prevents putting into gear AT derailleur control system of two |
| CN114442519A (en) * | 2021-12-20 | 2022-05-06 | 南京铁道职业技术学院 | Rail vehicle sliding fault simulation system |
-
2013
- 2013-12-27 CN CN201310737053.7A patent/CN103698638A/en not_active Withdrawn
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104539254A (en) * | 2014-12-30 | 2015-04-22 | 苏州优谱德精密仪器科技有限公司 | Signal filtering module |
| CN105827247A (en) * | 2016-03-21 | 2016-08-03 | 成都天进仪器有限公司 | Small signal output circuit for intelligent relay protection tester |
| CN112187277A (en) * | 2020-10-09 | 2021-01-05 | 中国船舶重工集团公司第七0七研究所九江分部 | Analog-digital signal conversion circuit with built-in test function |
| CN112187277B (en) * | 2020-10-09 | 2024-01-02 | 中国船舶重工集团公司第七0七研究所九江分部 | Analog-to-digital signal conversion circuit with built-in test function |
| CN114233845A (en) * | 2021-11-12 | 2022-03-25 | 中国北方车辆研究所 | Wheeled chariot prevents putting into gear AT derailleur control system of two |
| CN114442519A (en) * | 2021-12-20 | 2022-05-06 | 南京铁道职业技术学院 | Rail vehicle sliding fault simulation system |
| CN114442519B (en) * | 2021-12-20 | 2023-09-22 | 南京铁道职业技术学院 | Rail vehicle slides trouble analog system |
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Application publication date: 20140402 |