CN102944736B - Circuit for detecting wide-range, high-precision and multichannel currents based on optical couplings - Google Patents
Circuit for detecting wide-range, high-precision and multichannel currents based on optical couplings Download PDFInfo
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- CN102944736B CN102944736B CN201210478442.8A CN201210478442A CN102944736B CN 102944736 B CN102944736 B CN 102944736B CN 201210478442 A CN201210478442 A CN 201210478442A CN 102944736 B CN102944736 B CN 102944736B
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Abstract
The invention provides a circuit for detecting wide-range, high-precision and multichannel currents based on optical couplings. The circuit comprises a current sampling circuit, an analog selection circuit, an analog optical coupling circuit which are connected successively, a secondary differential amplification circuit, an impedance conversion circuit, an effective value conversion circuit and a data processing unit. The current sampling circuit is connected in series in a load by using a low resistance wire wound resistor to send a plurality of channels of low voltage signals to the analog selection circuit, and the analog selection circuit completes more choose one in time division; the analog optical coupling circuit separates a voltage signal portion and a data processing portion on left and right sides; the effective value conversion circuit converts alternating current voltage signals into direct current voltage signals; and the data processing unit samples and calculates the direct current signals to obtain actual current values. The circuit for detecting wide-range, high-precision and multichannel currents based on optical couplings has the advantages that the sampling reliability is high, loaded effects are few, multichannel integration is facilitated, and the cost is low; the system disturbance resisting capability is high; the sampling accuracy is high, and the range is wide; and small signal processing distortion is small. The whole system circuit is simple and easy to implement.
Description
Technical field
The present invention relates to analyze and measure control field, specifically a kind of wide region high-precision multi-path current detection circuit based on optocoupler.
Background technology
In road traffic signal controller, need to carry out real-time sample control to the alternating current numerical value of every street lamp driver output, to guarantee the correctness of output and the situation of change of monitoring load current, the security that improves traffic signal controlling machine.But at present a lot of these classes application are all based on transformer feedback sample, and transformer not only volume is large, the large and price of weight, has brought very burden to follow-up circuit board making and processing.Also have and adopt Hall element to sample, but Hall element cost is high, volume is unfavorable for greatly hyperchannel service condition.
Summary of the invention
The object of the invention is to overcome the deficiencies in the prior art, a kind of multi-channel high-accuracy alternating current numerical value testing circuit is provided, its antijamming capability is strong, simple in structure, use cost is low, high isolation, and precision is high, measurement range is wide, safe and reliable, and volume is little, and to be easy to hyperchannel integrated.
According to technical scheme provided by the invention, the described wide region high-precision multi-path current detection circuit based on optocoupler comprises: the current sampling circuit, analog selection circuit, optocoupler circuit, secondary differential amplifier circuit, impedance inverter circuit, effective value translation circuit, the data processing unit that connect successively; The output of Multi-current Sampling circuit is connected to analog selection circuit, described current sampling circuit is used the wire-wound resistor of the little resistance of high precision to be connected in load, by load current, at the two ends of resistance, produce voltage difference, then this multichannel small voltage signal is sent into analog selection circuit, by the timesharing of analog selection circuit, completed the function of multiselect one, the selection control end of analog selection circuit is connected with data processing unit after by digital light-coupled isolation; Described optocoupler circuit completes the isolation of the right and left voltage signal part and data processing section, and the elementary amplification that completes voltage signal; Described secondary differential amplifier circuit completes the amplification again of voltage signal; Described effective value translation circuit completes ac voltage signal and is transformed into d. c. voltage signal, and the A/D input end of the output of effective value translation circuit and data processing unit is connected; Described data processing unit completes the A/D sampling of direct current signal, then the result of sampling is carried out to analytic operation and draws actual current value, and outwards send data by Peripheral Interface.
Wherein, a road current sampling circuit comprises wire-wound resistor and sampling protective resistance, and the live wire of wire-wound resistor one end and alternating current is connected, and the other end is connected with bulb and is connected to analog selection circuit Yi road by sampling protective resistance and inputs.
Described analog selection circuit comprises that multichannel selects chip CD4051, and 16 pin of CD4051 are connected with+5V power supply, and the power supply of 7 pin and-5V is connected, and the power supply of 8 pin, 6 pin and 0V is connected and is connected with the live wire of alternating current; 13,14,15,12,1,5,2,4 pin of CD4051 are used for connecting Multi-current Sampling circuit; 9 pin of CD4051,10 pin, 11 pin are that 3 scale-of-two are selected control end, by being connected with data processing unit after digital light-coupled isolation, are used for selecting 8 input Zhong mono-tunnels, tunnel to carry out circuit sampling; 3 pin of CD4051 are that output pin is connected with the input end of optocoupler circuit.
Described optocoupler circuit comprises isolated amplifier HCPL7840,3 pin of the 9th resistance one end and described CD4051 are connected, 2 pin of the 9th resistance other end and HCPL7840 are connected and are connected with the anode tap of the second diode with the cathode terminal of the first diode, by the first diode and the second diode, pull down to 0V current potential; 1 pin of HCPL7840 is connected respectively the right and left voltage signal partly and the operating voltage of data processing section with 8 pin, 3 pin, 4 pin of HCPL7840 connect 0V current potential, 5 pin connect the ground of data processing section, 6 pin of HCPL7840 and 7 pin are negative pole and positive poles of difference output, are connected respectively with the input of secondary differential amplifier circuit.
Described secondary differential amplifier circuit comprises the first operational amplifier, and the first operational amplifier in-phase input end connects the positive pole of optocoupler circuit difference output by the tenth resistance, and by the parallel branch ground connection of the 12 resistance and the first electric capacity; The first operational amplifier inverting input connects the negative pole of optocoupler circuit difference output by the 11 resistance, and by the 13 resistance, is connected the output terminal of the first operational amplifier with the parallel branch of the second electric capacity; The output terminal of the first operational amplifier is the output stage of secondary differential amplifier circuit, is connected with the input end of impedance inverter circuit.
Described impedance inverter circuit comprises the second operational amplifier, the in-phase input end of the second operational amplifier is connected with the output terminal of the first operational amplifier, the inverting input of the second operational amplifier is connected with the output terminal of the second operational amplifier by the 14 resistance, the output terminal of the second operational amplifier is the output terminal of impedance inverter circuit, is connected with the input end of effective value translation circuit.
Described effective value translation circuit comprises effective measurement value transformer AD536AJH, and 4 pin of AD536AJH connect the output terminal of impedance inverter circuit by the 15 resistance, and pulls down to ground by the 3rd electric capacity; 1 pin of AD536AJH is all connected with ground with 2 pin, and 3 pin of AD536AJH connect positive source, and 5 pin of AD536AJH connect power cathode, and 6 pin of AD536AJH are connected by 3 pin of the 6th electric capacity and AD536AJH; 8 pin of one end of the 17 resistance and AD536AJH are connected and 10 pin by the 4th electric capacity and AD536AJH are connected, and the other end of the 17 resistance pulls down to ground by the 7th electric capacity, and as the output terminal of imitating value transform circuit; 9 pin of one end of the 16 resistance and AD536AJH are connected, and pull down to ground by the 5th electric capacity, and 10 pin of the other end of the 16 resistance and AD536AJH are connected; The output terminal of effective value translation circuit is connected with the A/D of data processing unit end.
Described data processing unit can adopt STM32F103RC chip.
Advantage of the present invention is: the resistance by the little resistance of connecting carrys out sample rate current, makes the reliability of sampling high, and little on the impact of load, sensing range is wide, is convenient to hyperchannel integrated, and cost is low; Use the isolation of optocoupler settling signal, make system safer, antijamming capability is strong; Adopt 10 A/D, make sampling precision high, wide ranges; Adopt effective value translation circuit to make small signal process distortion little, accuracy is high.Whole system circuit is simple, and thinking is clear and definite, easily implements.
Accompanying drawing explanation
Fig. 1 is circuit structure block diagram of the present invention.
Fig. 2 current sampling circuit and analog selection circuit theory diagrams.
Fig. 3 optocoupler circuit, secondary differential amplifier circuit, impedance inverter circuit schematic diagram.
Fig. 4 effective value translation circuit schematic diagram.
Embodiment
Below in conjunction with drawings and Examples, the invention will be further described.
As shown in Figure 1, the described wide region high-precision multi-path current detection circuit based on optocoupler comprises: the current sampling circuit, analog selection circuit, optocoupler circuit, secondary differential amplifier circuit, impedance inverter circuit, effective value translation circuit, the data processing unit that connect successively.By described optocoupler circuit, completed the isolation of left side voltage signal part and right side data processing section.
Current sample is partly by Multi-current Sampling the electric circuit constitute, described current sampling circuit is used is that the wire-wound resistor of the little resistance of high precision is connected in load, by load current, at the two ends of resistance, produce voltage difference, then this multichannel small voltage signal is sent into analog selection circuit; The timesharing of described analog selection circuit completes the function of multiselect one, and the output of described analog selection circuit is connected to optocoupler circuit; Described optocoupler circuit completes the isolation of voltage signal part and data processing section, improves safety and the antijamming capability of system, and suitably completes elementary amplification; The output of optocoupler circuit is connected with secondary differential amplifier circuit, and described secondary differential amplifier circuit completes the amplification again of voltage signal, can adjust voltage signal enlargement factor here and reach the scope that we want; The output of secondary differential amplifier circuit is connected with impedance inverter circuit, and it is low that described impedance inverter circuit makes the signal of input have output impedance, and the feature that driving force is strong, is convenient to the input of subsequent process circuit, improves accuracy and antijamming capability; The output of described impedance inverter circuit is connected with effective value translation circuit, and described effective value translation circuit completes ac voltage signal and is transformed into d. c. voltage signal; The A/D input end of the output of effective value translation circuit and data processing unit is connected; Described data processing unit completes the A/D sampling of direct current signal, then the result of sampling is carried out to analytic operation and draws actual current value, owing to adopting the A/D of 10, so precision can reach 1/1000 precision.Described data processing unit can send to other display terminal by serial ports the data of processing.
As shown in Figure 2, described current sampling circuit is to be comprised of the wire-wound resistor RL1 and the sampling protective resistance R1 that are connected in load circuit.Wire-wound resistor RL1 is the little resistance sampling resistor of high precision; the live wire AC/L of its one end and alternating current is connected; the other end is connected with traffic lights LAMP1 and is connected to analog selection circuit Yi road by sampling protective resistance R1 and inputs, and the needs on border can reach the such sample circuit in 8 roads factually.
Described analog selection circuit comprises that multichannel selects chip CD4051, and 16 pin of CD4051 are connected with+5V power supply, and the power supply of 7 pin and-5V is connected, and the power supply of 8 pin, 6 pin and 0V is connected and is connected with the live wire AC/L of alternating current; 13,14,15,12,1,5,2,4 pin of CD4051 can connect nearly 8 road current sampling circuits; 9 pin of CD4051,10 pin, 11 pin are that 3 scale-of-two are selected control end, by being connected with data processing unit after digital light-coupled isolation, are used for selecting 8 input Zhong mono-tunnels, tunnel to carry out circuit sampling; 3 pin of CD4051 are that output pin is connected with the input end of optocoupler circuit.
As shown in Figure 3, described optocoupler circuit comprises isolated amplifier HCPL7840,3 pin of the 9th resistance R 9 one end and described CD4051 are connected, 2 pin of the 9th resistance R 9 other ends and HCPL7840 are connected and are connected with the anode tap of the second diode D2 with the cathode terminal of the first diode D1, by the first diode D1 and the second diode D2, pull down to 0V current potential; 1 pin of HCPL7840 (is two groups of incoherent power supplys with the operating voltage that 8 pin are connected respectively the right and left voltage signal part and data processing section, their ground keeps apart), 3 pin, 4 pin of HCPL7840 connect 0V current potential, 5 pin connect the ground of data processing section, 6 pin of HCPL7840 and 7 pin are negative pole and positive poles of difference output, are connected respectively with the input of secondary differential amplifier circuit.
Described secondary differential amplifier circuit consists of dual operational amplifier LM258 with impedance inverter circuit: 7 pin of one end of the tenth resistance R 10 and HCPL7840 are connected, 3 pin of the other end and LM258 are connected, and pull down to ground by the parallel branch of the 12 resistance R 12 and the first capacitor C 1; 6 pin of one end of the 11 resistance R 11 and HCPL7840 are connected, 2 pin of the other end and LM258 are connected, and be connected by the 13 the resistance R 13 and parallel branch of the second capacitor C 2 and 1 pin of LM258,1 pin of LM258 is the output stage of secondary differential amplifier circuit, is connected with the input end of impedance inverter circuit.Described impedance inverter circuit comprises: 5 pin of LM258 are connected with 1 pin, and 6 pin are connected with 7 pin by the 14 resistance R 14, and 7 pin of LM258 are output terminals of impedance inverter circuit, are connected with the input end of effective value translation circuit.
As shown in Figure 4, described effective value translation circuit is mainly to consist of effective value transducer AD536AJH: 7 pin of one end of the 15 resistance R 15 and LM258 are connected, and 4 pin of the other end and AD536AJH are connected, and pull down to ground by the 3rd capacitor C 3.1 pin of AD536AJH is all connected with ground with 2 pin.3 pin of AD536AJH are connected with positive source+V50.5 pin of AD536AJH are connected with power cathode-V50.6 pin of AD536AJH are connected by 3 pin of the 6th capacitor C 6 and AD536AJH.7 pin of AD536AJH are unsettled not to be connect.8 pin of one end of the 17 resistance R 17 and AD536AJH are connected and 10 pin by the 4th capacitor C 4 and AD536AJH are connected, and the other end of the 17 resistance R 17 pulls down to ground by the 7th capacitor C 7, and as the output terminal of imitating value transform circuit.9 pin of one end of the 16 resistance R 16 and AD536AJH are connected, and pull down to ground by the 5th capacitor C 5, and 10 pin of the other end of the 16 resistance R 16 and AD536AJH are connected.The output of effective value translation circuit is connected with the A/D of data processing unit end.
The STM32F103RC chip of the main Shi You ST of described data processing unit company forms: STM32F103RC inside is integrated with 10 A/D unit, can carry out A/D conversion to the output of effective value translation circuit, and carry out the calculating of the actual current value size of finishing dealing with of data, and the current value of each passage reality is sent to display terminal by serial ports.
Claims (2)
1. the wide region high-precision multi-path current detection circuit based on optocoupler, comprises the current sampling circuit, analog selection circuit, optocoupler circuit, secondary differential amplifier circuit, impedance inverter circuit, effective value translation circuit, the data processing unit that connect successively; The output of Multi-current Sampling circuit is connected to analog selection circuit, described current sampling circuit is used the wire-wound resistor of the little resistance of high precision to be connected in load, by load current, at the two ends of resistance, produce voltage difference, then this multichannel small voltage signal is sent into analog selection circuit, by the timesharing of analog selection circuit, completed the function of multiselect one, the selection control end of analog selection circuit is connected with data processing unit after by digital light-coupled isolation; Described optocoupler circuit completes the isolation of the right and left voltage signal part and data processing section, and the elementary amplification that completes voltage signal; Described secondary differential amplifier circuit completes the amplification again of voltage signal; Described effective value translation circuit completes ac voltage signal and is transformed into d. c. voltage signal, and the A/D input end of the output of effective value translation circuit and data processing unit is connected; Described data processing unit completes the A/D sampling of direct current signal, then the result of sampling is carried out to analytic operation and draws actual current value, and outwards send data by Peripheral Interface;
It is characterized in that: described analog selection circuit comprises that multichannel selects chip CD4051,16 pin of CD4051 are connected with+5V power supply, and the power supply of 7 pin and-5V is connected, and the power supply of 8 pin, 6 pin and 0V is connected and is connected with the live wire of alternating current; 13,14,15,12,1,5,2,4 pin of CD4051 are used for connecting Multi-current Sampling circuit; 9 pin of CD4051,10 pin, 11 pin are that 3 scale-of-two are selected control end, by being connected with data processing unit after digital light-coupled isolation, are used for selecting 8 input Zhong mono-tunnels, tunnel to carry out circuit sampling; 3 pin of CD4051 are that output pin is connected with the input end of optocoupler circuit;
Described optocoupler circuit comprises isolated amplifier HCPL7840,3 pin of the 9th resistance (R9) one end and described CD4051 are connected, 2 pin of the 9th resistance (R9) other end and HCPL7840 are connected and are connected with the anode tap of the second diode (D2) with the cathode terminal of the first diode (D1), by the first diode (D1) and the second diode (D2), pull down to 0V current potential; 1 pin of HCPL7840 is connected respectively the right and left voltage signal partly and the operating voltage of data processing section with 8 pin, 3 pin, 4 pin of HCPL7840 connect 0V current potential, 5 pin connect the ground of data processing section, 6 pin of HCPL7840 and 7 pin are negative pole and positive poles of difference output, are connected respectively with the input of secondary differential amplifier circuit;
Described secondary differential amplifier circuit comprises the first operational amplifier, the first operational amplifier in-phase input end connects the positive pole of optocoupler circuit difference output by the tenth resistance (R10), and by the parallel branch ground connection of the 12 resistance (R12) and the first electric capacity (C1); The first operational amplifier inverting input connects the negative pole of optocoupler circuit difference output by the 11 resistance (R11), and by the 13 resistance (R13), is connected the output terminal of the first operational amplifier with the parallel branch of the second electric capacity (C2); The output terminal of the first operational amplifier is the output stage of secondary differential amplifier circuit, is connected with the input end of impedance inverter circuit;
Described impedance inverter circuit comprises the second operational amplifier, the in-phase input end of the second operational amplifier is connected with the output terminal of the first operational amplifier, the inverting input of the second operational amplifier is connected with the output terminal of the second operational amplifier by the 14 resistance (R14), the output terminal of the second operational amplifier is the output terminal of impedance inverter circuit, is connected with the input end of effective value translation circuit;
Described effective value translation circuit comprises effective measurement value transformer AD536AJH, and 4 pin of AD536AJH connect the output terminal of impedance inverter circuit by the 15 resistance (R15), and pulls down to ground by the 3rd electric capacity (C3); 1 pin of AD536AJH is all connected with ground with 2 pin, and 3 pin of AD536AJH connect positive source (+V50), and 5 pin of AD536AJH connect power cathode (V50), and 6 pin of AD536AJH are connected by 3 pin of the 6th electric capacity (C6) and AD536AJH; And 8 pin of AD536AJH are connected and 10 pin by the 4th electric capacity (C4) and AD536AJH are connected in the 17 one end of resistance (R17), the other end of the 17 resistance (R17) pulls down to ground by the 7th electric capacity (C7), and as the output terminal of imitating value transform circuit; The 16 one end of resistance (R16) and 9 pin of AD536AJH are connected, and pull down to ground by the 5th electric capacity (C5), and the 16 other end of resistance (R16) and 10 pin of AD536AJH are connected; The output terminal of effective value translation circuit is connected with the A/D of data processing unit end.
2. the wide region high-precision multi-path current detection circuit based on optocoupler as claimed in claim 1, is characterized in that, described data processing unit adopts STM32F103RC chip.
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| CN201210478442.8A CN102944736B (en) | 2012-11-22 | 2012-11-22 | Circuit for detecting wide-range, high-precision and multichannel currents based on optical couplings |
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| CN103543319B (en) * | 2013-09-06 | 2016-06-15 | 国家电网公司 | The measuring method of the high-precision rapid survey circuit of power system inner width range current |
| CN104374995A (en) * | 2014-11-17 | 2015-02-25 | 擎翌(上海)智能科技有限公司 | 220 VAC load current detecting circuit |
| CN106645927A (en) * | 2017-01-23 | 2017-05-10 | 上海理工大学 | Power detection circuit for switching power supply |
| CN107192958B (en) * | 2017-05-26 | 2019-08-06 | 上海空间电源研究所 | Test method for the failure of solar battery array hot vacuum environment |
| CN109387691A (en) * | 2018-12-14 | 2019-02-26 | 中核新科（天津） 精密机械制造有限公司 | The atomic low current linear measuring circuit of femto-ampere grade |
| CN110032114A (en) * | 2019-04-24 | 2019-07-19 | 江苏泰坤环保科技有限公司 | A kind of high-precision analog signal acquisition processing circuit |
| CN113949449B (en) * | 2021-09-24 | 2023-11-17 | 昂纳科技(深圳)集团股份有限公司 | Photodiode detection circuit, optical module, monitoring system and monitoring method thereof |
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| JPH05209903A (en) * | 1992-01-31 | 1993-08-20 | Tokyo Electric Power Co Inc:The | Measurement of asymmetric component of ac current |
| CN2603399Y (en) * | 2002-12-02 | 2004-02-11 | 北京曙光天演信息技术有限公司 | Measuring card for three-phase ac power |
| CN2694283Y (en) * | 2004-01-13 | 2005-04-20 | 北京金自天正智能控制股份有限公司 | Isolated form synchronizing voltage metering circuit |
| CN201449411U (en) * | 2009-07-02 | 2010-05-05 | 苏州经贸职业技术学院 | Multichannel current sampling circuit |
| CN201637773U (en) * | 2010-04-13 | 2010-11-17 | 浙江容大电力设备制造有限公司 | Collecting circuit of true effective value of multi-path alternating current signals |
| CN201886075U (en) * | 2010-12-16 | 2011-06-29 | 河南光彩电器有限公司 | Current signal collection module |
| CN201955389U (en) * | 2010-12-22 | 2011-08-31 | 川铁电气（天津）集团有限公司 | Single-phase alternating-current voltage and current acquisition circuit |
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Address after: 214101 Xishan Economic Development Zone, Jiangsu Province, science and Technology Industrial Park, No. 1, No. Patentee after: Jiangsu aerospace Polytron Technologies Inc Address before: 214101 Xishan, Jiangsu, East Road, South District, No. 39, No. Patentee before: Jiangsu Daway Technologies Co., Ltd. |