CN204216846U - Based on the photovoltaic combiner box measure and control device of sample resistance - Google Patents
Based on the photovoltaic combiner box measure and control device of sample resistance Download PDFInfo
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- CN204216846U CN204216846U CN201420456187.1U CN201420456187U CN204216846U CN 204216846 U CN204216846 U CN 204216846U CN 201420456187 U CN201420456187 U CN 201420456187U CN 204216846 U CN204216846 U CN 204216846U
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Abstract
A kind of photovoltaic combiner box measure and control device based on sample resistance, comprise the isolation sampling section and control survey part that are electrically isolated from one another, described isolation sampling section is powered with insulating power supply, comprise multiple sampling resistor, simulant electronic switch, potential-divider network, linear optical coupling, described multiple sampling resistor is serially connected in each photovoltaic group string respectively, pressure drop on the corresponding described sampling resistor of described simulant electronic switch receiving key switching signal collection, and the current information being amplified the photovoltaic group string exporting place by described first linear optical coupling; Described potential-divider network is connected between described positive and negative bus-bar, by the voltage step-down between positive and negative bus-bar, and by described second linear optical coupling output voltage information; Described control survey part receives and according to described current information and described information of voltage, exports described switching over signal to described isolation sampling section.Sampling resistor testing current scheme can effectively reduce the cost of measure and control device.
Description
Technical field
The utility model relates to photovoltaic generation header box monitoring field, particularly relates to a kind of photovoltaic combiner box measure and control device based on sample resistance.
Background technology
Photovoltaic combiner box is the headend equipment of photo-voltaic power generation station, its role is to the subregion on-site supervision of photovoltaic arrays and distally the operating mode of the whole photovoltaic cell component of daemon software Real-Time Monitoring provides Data support.Because usage quantity is numerous, photovoltaic combiner box accounts for suitable great share for the investment of photovoltaic plant.In order to the market competition advantage of improving product, the cost space of this type product of excavation that each header box producer all does one's utmost; Research emphasis is collapsed into header box measure and control device cost.
The header box measure and control device of current main flow adopts punching Hall current sensor, or single-chip type Hall current sensor, as the MLX91210 etc. of ACS712 and Melexis that U.S. Allegro produces, the former cost is the highest, and temperature performance is poor, and certainty of measurement is low, advantage has good isolation performance, the latter's cost slightly low (for the former 1/3rd), temperature characterisitic and precision are better than the former, and shortcoming is that isolation performance is slightly poor.The current sensor that measurement and control unit configures will take the cost amount of 1/3rd usually.And a lot of product does not support adjusting of on-site parameters, once there is the deviation that certainty of measurement is excessive, just feel simply helpless, must change measure and control device could normally run, and extends maintenance period and adds O&M cost.
Utility model content
Based on this, be necessary to provide a kind of low cost, the high-precision photovoltaic combiner box measure and control device based on sample resistance.
Based on a photovoltaic combiner box measure and control device for sample resistance, be arranged between positive and negative bus-bar, comprise the isolation sampling section and control survey part that are electrically isolated from one another, wherein,
Described isolation sampling section is powered with insulating power supply, comprise multiple sampling resistor, simulant electronic switch, potential-divider network, the first linear optical coupling and the second linear optical coupling, described multiple sampling resistor is serially connected in each photovoltaic group string respectively, pressure drop on the corresponding described sampling resistor of described simulant electronic switch receiving key switching signal collection, and the current information being amplified the photovoltaic group string exporting place by described first linear optical coupling;
Described potential-divider network is connected between described positive and negative bus-bar, by the voltage step-down between positive and negative bus-bar, and by described second linear optical coupling output voltage information;
Described control survey part receives and according to described current information and described information of voltage, exports described switching over signal to described isolation sampling section.
Further, described isolation sampling section circuit is as a reference point with the current potential of described positive bus, and the input reference edge of described simulant electronic switch, the first linear optical coupling and the second linear optical coupling is connected with arbitrary bus-bar port of described positive bus.
Further, described control survey part comprises single-chip microcomputer, the first difference channel, the second difference channel, the first filter circuit, the second filter circuit and optocoupler channel switching circuit, wherein:
Described in the input termination of described first difference channel, the output of the first linear optical coupling, receives described current information, and is input to the current sample passage of described single-chip microcomputer after described current information being outputted to described first filter circuit filtering;
Described in the input termination of described second difference channel, the output of the second linear optical coupling, receives described information of voltage, and is input to the voltage sample passage of described single-chip microcomputer after described information of voltage being outputted to described second filter circuit filtering;
Described single-chip microcomputer is by exporting the poll of described switching over signal realization to each current channel.
Further, described sampling resistor is copper-manganese resistance.
Further, described simulant electronic switch adopts chip 74HC4051 to form.
Further, first, second linear optical coupling described adopts chip ACPL-C79B, and makes it be operated in Differential Input pattern.
Further, described insulating power supply adopts the positive activation type isolating switch power of discrete device composition, provides a road+5V power supply to the input of described simulant electronic switch, the first linear optical coupling and the second linear optical coupling.
Further, described insulating power supply adopts EE16 high frequency transformer.
Further, described potential-divider network comprises the first divider resistance, the second divider resistance, the positive input terminal of positive bus and described second linear optical coupling described in first termination of described first divider resistance, second end of the first divider resistance described in the first termination of described second divider resistance and the negative input end of described second linear optical coupling, the second termination negative bus of described second divider resistance.
Further, also comprise operation push-button, the real current value that the photovoltaic group that described control survey part also inputs for receiving this operation push-button is ganged up also performs straightened up in place order, can carry out sampling adjustment to any described photovoltaic group string.
Photovoltaic combiner box measure and control device based on sample resistance adopts cheap sampling resistor testing current scheme can effectively reduce the cost of measure and control device; We use shunt as the sampling resistor measuring photovoltaic group crosstalk stream thus, the small-power insulating power supply of high isolation performance and rational circuit reference point is coordinated to choose, by the simplification to original circuit, under the prerequisite of not sacrificing isolation, reliability, anti-interference, make the cost of measure and control device be tightened, more traditional scheme has better stability, good temperature characteristics and higher sampling precision.
Accompanying drawing explanation
Fig. 1 is the system block diagram of photovoltaic combiner box measure and control device in the utility model embodiment;
Fig. 2 is that the channel current of photovoltaic combiner box measure and control device in the utility model embodiment measures commutation circuit figure;
Fig. 3 is the sampling resistor testing current channel linear degree site-test analysis figure in the utility model embodiment;
Fig. 4 is the gain temperature performance plot of the linear optical coupling in the utility model embodiment;
Fig. 5 is the button operation flow chart in the utility model embodiment.
Embodiment
In order to make the technical problems to be solved in the utility model, technical scheme and beneficial effect clearly understand, below in conjunction with drawings and Examples, the utility model is further elaborated.Should be appreciated that specific embodiment described herein only in order to explain the utility model, and be not used in restriction the utility model.
Refer to Fig. 1, be arranged between positive and negative bus-bar in the utility model preferred embodiment based on the photovoltaic combiner box measure and control device of sample resistance, measure and control device comprises the isolation sampling section 1 and control survey part 2 that are electrically isolated from one another.In the present embodiment, between positive and negative bus-bar, be connected to 16 photovoltaic group strings 1#, 2# ... 16# (i#).
Described isolation sampling section 1 is powered with insulating power supply 3, comprise multiple sampling resistor Ri (R1, R2 ... R16), simulant electronic switch 7, potential-divider network 15, first linear optical coupling 6 and the second linear optical coupling 13, described multiple sampling resistor Ri is serially connected in each photovoltaic group string i# respectively, pressure drop on the corresponding described sampling resistor of described simulant electronic switch 7 receiving key switching signal collection, and the current information being amplified the photovoltaic group string i# exporting place according to this pressure drop by described first linear optical coupling 6.Described potential-divider network 15 is connected between described positive and negative bus-bar, by the voltage step-down between positive and negative bus-bar, and according to this voltage drop by described second linear optical coupling 13 output voltage information; Described control survey part 2 receives and according to described current information and described information of voltage, export described switching over signal to described isolation sampling section 1 and switch acquisition circuit with control simulation electronic switch 7, gather pressure drop on corresponding sampling resistor Ri to obtain the current information of the photovoltaic group string i# at place.
Sampling resistor Ri replaces traditional Hall current sensor, group to be gone here and there total voltage dividing potential drop by large resistance power samples resistance Ri and accurate divider resistance by isolation sampling section 1, and the size of the total remittance abroad voltage of calculating of being sampled for control survey part 2 by linear optical coupling isolation, better temperature performance and certainty of measurement is obtained than conventional Hall current sensor scheme when not sacrificing isolation performance, and reduce the hardware cost of header box measurement and control unit, improve the manufacture convenience of header box thus reduce production cost, strengthen the cost competitiveness that its large-scale production manufactures.
The circuit of isolation sampling section 1 is with the current potential of described positive bus as a reference point 4, and the reference edge of simulant electronic switch 7, first linear optical coupling 6 and the second linear optical coupling 13 is connected with arbitrary bus-bar port of positive bus.With reference to figure 1, in the present embodiment, isolate sampling section 1 with the cathode output end of first photovoltaic group string 1# on positive bus for reference point 4.Each sampling input of isolation sampling section 1 can not exceed the pressure drop of sampling resistor Ri relative to the voltage of reference point 4, consider that photovoltaic group string i# current limitation is 15A, then the pressure drop on sampling resistor Ri is: U
r=i × r=15 × 0.005 Ω=0.075V; Common-mode voltage in visible isolation sampling section 1 is safe, and has very large allowance.
In one embodiment, sampling resistor Ri adopts copper-manganese resistance.Preferably, copper-manganese resistance employing specification is: 5m Ω 3W 1%40ppm.In other embodiments, other precision resisters can be used to replace according to art technology.In the present embodiment, 16 sampling resistor Ri are placed on the positive pole output loop of 16 photovoltaic group string i#, are measured the size (current information) of photovoltaic group crosstalk stream i# by the pressure drop of measuring on sampling resistor Ri.
In one embodiment, with reference to figure 2, simulant electronic switch adopts chip 74HC4051 to form.In the present embodiment, adopt four 74HC4051 chips to realize the switching of 16 pairs of differential signals, the pressure drop on 16 sampling resistor Ri is the input being connected to the first linear optical coupling 6 by 16 pairs of electronic switches with difference modes.As shown in Figure 2, chip U26, chip U30 realize the pressure drop ' I+_1 ' to the first eight road sample resistance, ' I-_1 ' ~ ' I+_8 ', and ' I-_8 ' switches to the input of the first linear optical coupling 6 (U33) successively; Chip U24, chip U32 realize the pressure drop ' I+_9 ' of Dui Hou eight road sample resistance, ' I-_9 ' ~ ' I+_16 ', and ' I-_16 ' switches to the input of the first linear optical coupling 6 (U33) successively.
Please continue to refer to Fig. 1, the first linear optical coupling 6, second linear optical coupling 13 adopts chip ACPL-C79B, and makes it be operated in Differential Input pattern, the error that the deviation thoroughly avoiding position, place causes.When can eliminate single-ended sampling configuration due to earthy deviation cause sampling inaccurate, and due to the difference of electric current, earth potential presents non-linear difference, and software cannot adjustment, and in the present embodiment, the gain of the first linear optical coupling 6, second linear optical coupling 13 is 8.
The positive activation type isolating switch power that insulating power supply 3 adopts discrete device to form, provides a road+5V power supply to described simulant electronic switch 7, first linear optical coupling 6 and the second linear optical coupling 13.Namely one end of the secondary coil of insulating power supply 3 is connected with positive bus and ground connection forms reference point, at the other end output+5V power supply of secondary coil.Preferably, described insulating power supply 3 adopts EE16 high frequency transformer, realizes 3.5kV power frequency isolation withstand voltage properties.
In the present embodiment, described potential-divider network 15 comprises the first divider resistance R17, the second divider resistance R18, the positive input terminal of positive bus and described second linear optical coupling 13 described in first termination of described first divider resistance R17, second end of the first divider resistance R17 described in first termination of described second divider resistance R18 and the negative input end of described second linear optical coupling 13, the second termination negative bus of described second divider resistance R18.The common point of potential-divider network 15 is located at the positive bus of header box, and the signal after decay is received the negative input end of the second linear optical coupling 13, and common point access positive input terminal, realizes positive polarity and export.Preferably, the first divider resistance R17 is 10M Ω 1W power resistor; Second divider resistance R18 is 1.5K Ω 0.1% precision resistance, voltage proportional on second divider resistance R18 is in total output voltage of header box, accessed the differential input end of the second linear optical coupling 13, and positive input terminal receives positive bus, the output making the second linear optical coupling 13 is positive polarity, reaches the object of not sacrificing sampling precision.
Please continue to refer to Fig. 1, the circuit of control survey part 2 comprises single-chip microcomputer (9 and 17), the first difference channel 8, second difference channel 14, first filter circuit 10, second filter circuit 11 and optocoupler channel switching circuit 5, and optocoupler channel switching circuit 5 has multiple photoelectrical coupler to form.Single-chip microcomputer can adopt the ARM single-chip microcomputer of 12 ADC (Analog-to-Digital Converter, analog to digital converter).Just by the separately signal of the logic control part MCU (17) of single-chip microcomputer and ADC (9) part in Fig. 1.That is, single-chip microcomputer also can use the chip not having ADC to be total to energy, and needs additional ADC.
Described in the input termination of the first difference channel 8, the output of the first linear optical coupling 6, receives described current information, and is input to the current sample passage of described single-chip microcomputer after described current information being outputted to described first filter circuit 10 filtering.Described in the input termination of described second difference channel 14, the output of the second linear optical coupling 13, receives described information of voltage, and is input to the voltage sample passage of described single-chip microcomputer after described information of voltage being outputted to described second filter circuit 11 filtering.Described single-chip microcomputer is by exporting the poll (orderly or random access gather current information) of described switching over signal realization to each current channel (photovoltaic group string i#).Described single-chip microcomputer receives and controls the corresponding channel conductive of described optocoupler channel switching circuit 5 according to described current information and described information of voltage output switch switching signal, to export described switching over signal, and then switch acquisition circuit with control simulation electronic switch 7, gather pressure drop on corresponding sampling resistor Ri to obtain the current information of the photovoltaic group string i# at place.
In the present embodiment, first difference channel 8, second difference channel 14 is as the U34A in Fig. 2 and peripheral circuit thereof, its multiplication factor is 5 times, and namely as maximum input 15A, the output voltage of the first difference channel 8, second difference channel 14 and the maximum input voltage of ADC are: U
adc=0.075 × 8 × 5=3V; Theoretic Measurement Resolution is: 15/4096=4mA;
Novel busbar box measure and control device based on sample resistance also comprises operation push-button (not shown), control survey part 2 is also for receiving the real current value of the photovoltaic group string i# passage of this operation push-button input and performing straightened up in place order, to carry out sampling adjustment to any described photovoltaic group string i#.
Further, also Default Value Parameter reconstruction can be performed by this operation push-button.In addition, Novel busbar box measure and control device support based on sample resistance is dispatched from the factory the automatic recovery of parameter, device software verifies the parameters run in single-chip microcomputer (correction parameter, unit address etc.) in real time, when check code is incorrect, automatically recover the parameter arranged when dispatching from the factory.
Further, when occurring dispatching from the factory parameter loss, program enables the system parameters of a set of acquiescence automatically, ensures that measurement result there will not be significant errors.
As shown in Figure 3, due to the existence of first, second linear optical coupling and operational amplifier (first, second difference channel) offset voltage, within causing 1A, transformation result is not in linear zone, so need employing 2 point calibration algorithm:
Wherein:
In formula, x1, x2 are respectively the sampled value of the first point (1A), second point (10A) correspondence; F (x1)=1A, f (x2)=10A;
About sampling resistor (copper-manganese resistance) Ri, provide following characteristic reference:
Because the high impedance of linear optical coupling inputs, the change of the Ron of simulant electronic switch is not contributed output error; As shown in Figure 4, being 8.2 25 DEG C time, is 8.23 when-40 DEG C in the gain temperature drift of linear optical coupling; If do not consider the error of rear class difference channel, the error that examination front end produces relative to 25 DEG C-40 DEG C time is:
Visible, adopt the temperature characterisitic that cheap sampling resistor testing current scheme is more excellent compared with the performance of conventional Hall sensor plan.
Please refer to Fig. 5, the utility model embodiment also provides the method for the manual adjustment of a kind of in-site measurement precision.
The phenomenon that respective channel measured value deviation is excessive is there is at the scene because certain specific factor causes observing and controlling to be contained in, operation maintenance personnel can test the actual current size of this passage by hand-held current clamp, carry out straightened up in place by the method described in Fig. 3 to respective channel.
The above embodiment only have expressed several execution mode of the present utility model; not in order to limit the utility model; all do within spirit of the present utility model and principle any amendment, equivalent to replace and improvement etc., all should be included within protection range of the present utility model.
Claims (10)
1. based on a photovoltaic combiner box measure and control device for sample resistance, be arranged between positive and negative bus-bar, it is characterized in that, comprise the isolation sampling section and control survey part that are electrically isolated from one another, wherein,
Described isolation sampling section is powered with insulating power supply, comprise multiple sampling resistor, simulant electronic switch, potential-divider network, the first linear optical coupling and the second linear optical coupling, described multiple sampling resistor is serially connected in each photovoltaic group string respectively, pressure drop on the corresponding described sampling resistor of described simulant electronic switch receiving key switching signal collection, and the current information being amplified the photovoltaic group string exporting place by described first linear optical coupling;
Described potential-divider network is connected between described positive and negative bus-bar, by the voltage step-down between positive and negative bus-bar, by described second linear optical coupling output voltage information;
Described control survey part receives and according to described current information and described information of voltage, exports described switching over signal to described isolation sampling section.
2. the photovoltaic combiner box measure and control device based on sample resistance according to claim 1, it is characterized in that, described isolation sampling section circuit is as a reference point with the current potential of described positive bus, and the reference edge of described simulant electronic switch, the first linear optical coupling and the second linear optical coupling is connected with arbitrary bus-bar port of described positive bus.
3. the photovoltaic combiner box measure and control device based on sample resistance according to claim 1, it is characterized in that, described control survey part comprises single-chip microcomputer, the first difference channel, the second difference channel, the first filter circuit, the second filter circuit and optocoupler channel switching circuit, wherein:
Described in the input termination of described first difference channel, the output of the first linear optical coupling, receives described current information, and is input to the current sample passage of described single-chip microcomputer after described current information being outputted to described first filter circuit filtering;
Described in the input termination of described second difference channel, the output of the second linear optical coupling, receives described information of voltage, and is input to the voltage sample passage of described single-chip microcomputer after described information of voltage being outputted to described second filter circuit filtering;
Described single-chip microcomputer is by exporting the poll of described switching over signal realization to each current channel.
4. the photovoltaic combiner box measure and control device based on sample resistance according to claim 1, is characterized in that, described sampling resistor is copper-manganese resistance.
5. the photovoltaic combiner box measure and control device based on sample resistance according to claim 1,2 or 3, is characterized in that, described simulant electronic switch adopts chip 74HC4051 to form.
6. the photovoltaic combiner box measure and control device based on sample resistance according to claim 1,2 or 3, is characterized in that, first, second linear optical coupling described adopts chip ACPL-C79B, and makes it be operated in Differential Input pattern.
7. the photovoltaic combiner box measure and control device based on sample resistance according to claim 1, it is characterized in that, described insulating power supply adopts the positive activation type isolating switch power of discrete device composition, provides a road+5V power supply to the input of described simulant electronic switch, the first linear optical coupling and the second linear optical coupling.
8. the photovoltaic combiner box measure and control device based on sample resistance according to claim 7, is characterized in that, described insulating power supply adopts EE16 high frequency transformer.
9. the photovoltaic combiner box measure and control device based on sample resistance according to claim 1, it is characterized in that, described potential-divider network comprises the first divider resistance, the second divider resistance, the positive input terminal of positive bus and described second linear optical coupling described in first termination of described first divider resistance, second end of the first divider resistance described in the first termination of described second divider resistance and the negative input end of described second linear optical coupling, the second termination negative bus of described second divider resistance.
10. the photovoltaic combiner box measure and control device based on sample resistance according to claim 1, it is characterized in that, also comprise operation push-button, the real current value that the photovoltaic group that described control survey part also inputs for receiving this operation push-button is ganged up also performs straightened up in place order, to carry out sampling adjustment to any described photovoltaic group string.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104167987A (en) * | 2014-08-13 | 2014-11-26 | 深圳市金宏威技术股份有限公司 | Photovoltaic combiner box measuring and control device based on sampling resistors |
| CN104167987B (en) * | 2014-08-13 | 2017-01-04 | 深圳市金宏威技术股份有限公司 | Photovoltaic combiner box measure and control device based on sample resistance |
| CN109975605A (en) * | 2019-04-02 | 2019-07-05 | 中国原子能科学研究院 | A kind of multi channel detector leakage current automatic measurement system |
-
2014
- 2014-08-13 CN CN201420456187.1U patent/CN204216846U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104167987A (en) * | 2014-08-13 | 2014-11-26 | 深圳市金宏威技术股份有限公司 | Photovoltaic combiner box measuring and control device based on sampling resistors |
| CN104167987B (en) * | 2014-08-13 | 2017-01-04 | 深圳市金宏威技术股份有限公司 | Photovoltaic combiner box measure and control device based on sample resistance |
| CN109975605A (en) * | 2019-04-02 | 2019-07-05 | 中国原子能科学研究院 | A kind of multi channel detector leakage current automatic measurement system |
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Address after: 518000 Guangdong city of Shenzhen province Nanshan District South Road No. 9 nine Wei new software park building 8 floor 701-712 room 7 Patentee after: Shenzhen Jinhongwei Technology Co., Ltd. Address before: 518057 Guangdong city of Shenzhen province Nanshan District high tech Zone nine new South Road No. 9, new software park building 8 floor 701-712 room 7 Patentee before: Shenzhen Jinhongwei Technology Co.,Ltd. |