CN104201714A - Another circuit for resisting potential-induced degradation of multi-parallel photovoltaic power generation system - Google Patents
Another circuit for resisting potential-induced degradation of multi-parallel photovoltaic power generation system Download PDFInfo
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- CN104201714A CN104201714A CN201410413934.8A CN201410413934A CN104201714A CN 104201714 A CN104201714 A CN 104201714A CN 201410413934 A CN201410413934 A CN 201410413934A CN 104201714 A CN104201714 A CN 104201714A
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- 238000010248 power generation Methods 0.000 title abstract description 6
- 230000015556 catabolic process Effects 0.000 title abstract description 4
- 238000006731 degradation reaction Methods 0.000 title abstract description 4
- 230000006698 induction Effects 0.000 claims description 6
- 238000000034 method Methods 0.000 abstract description 3
- 238000002955 isolation Methods 0.000 abstract 2
- 238000005516 engineering process Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000007935 neutral effect Effects 0.000 description 3
- 230000000694 effects Effects 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004411 aluminium Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 238000013016 damping Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The invention discloses another circuit for resisting potential-induced degradation of a multi-parallel photovoltaic power generation system. The circuit comprises N parallel photovoltaic inverters, the output ends of the N photovoltaic inverters are connected to the input end of a same isolation transformer, the output end of the isolation transformer is connected to a power grid, the input end of each photovoltaic inverter in the N photovoltaic inverters is connected with at least one solar panel, N is greater than or equal to 2, wherein the number of the cell panels connected to the input end of the first inverter is at least one greater than that connected to the input ends of other inverters. The cathode of the input end of only the first inverter in the N inverters is connected to the anodes of the M cell panels, and the cathodes of the cell panels are earthed. M is an integer, and M is greater than 0. Through the method, the cathodes of the input ends of the photovoltaic inverters can be prevented from generating negative pressure for the ground. Therefore, the potential-induced degradation of the photovoltaic cell panels in the photovoltaic power generation system is avoided, and meanwhile the earth leakage current problem of the inverters existing in the photovoltaic power generation system is solved.
Description
Technical field
The present invention relates to photovoltaic power generation technology field, specially refer to the potential electromotive force induction attenuator circuit under a kind of multi-machine parallel connection.
Background technology
At present in photovoltaic power generation technology, potential electromotive force decay (the English potential induced Degradation by name of photovoltaic module, PID) be newer photovoltaic module attenuation effect, along with photovoltaic system voltage is more and more higher, photovoltaic module internal cell sheet is also more and more higher to the low pressure of the earth, due to the aluminium matter frame ground connection of photovoltaic module, so the negative pressure that photovoltaic module metal edge frame over the ground just forms is also more and more higher, under high negative pressure, there is migration in the ion in the encapsulating material of photovoltaic module and the upper surface of photovoltaic module and lower surface material, not only form the damage of photovoltaic module oneself, also form the generating efficiency decay of photovoltaic module, thereby affect the decay of the fan-out capability of photovoltaic generating system.
Show from current technology, in order to prevent the anti-potential electromotive force decay of photovoltaic module, by the input of many same isolating transformers of photovoltaic DC-to-AC converter output termination, the output of isolating transformer gets access to grid, the negative pole of the input of every photovoltaic DC-to-AC converter is connect to the earth, the inside DC bus mid point of the normal work of photovoltaic DC-to-AC converter and the mid point equipotential of isolating transformer, it is the inside mid point equipotential of each photovoltaic DC-to-AC converter, because the cathode voltage of the input of each inverter is inconsistent, and the mid point of the DC bus of each inverter is waited for current potential, in the time that the input cathode voltage of photovoltaic DC-to-AC converter changes, the input cathode of photovoltaic DC-to-AC converter also can larger variation to the earth, there is larger leakage current, thereby cause the photovoltaic DC-to-AC converter cannot steady operation.
Summary of the invention
The object of this invention is to provide the potential electromotive force of a kind of anti-multi-machine parallel connection photovoltaic generating system induction attenuator circuit, the Ground leakage current technical problem out of control of bringing solving anti-potential electromotive force decay in existing photovoltaic generating system when.
First aspect, the application implements to provide the potential electromotive force induction of a kind of anti-plural parallel stage photovoltaic generating system attenuator circuit, and described circuit comprises:
The parallel connection of N platform photovoltaic DC-to-AC converter, described N platform photovoltaic DC-to-AC converter output is received the input of same isolating transformer, each photovoltaic DC-to-AC converter input in described N platform photovoltaic DC-to-AC converter connects at least one cell panel, the output voltage of described cell panel is identical, in described N platform photovoltaic DC-to-AC converter, only have the input cathode of First photovoltaic DC-to-AC converter to connect the positive pole of M piece cell panel output, the negative pole of M piece cell panel output connects the earth.Wherein N is integer, and N>=2.M is integer, and M>0;
The quantity of the input termination cell panel of described First photovoltaic DC-to-AC converter, is greater than the quantity of the input termination cell panel of other each photovoltaic DC-to-AC converters in N platform photovoltaic DC-to-AC converter.
In conjunction with first aspect, in the mode of the possible realization of the first, the quantity of the input termination cell panel of other photovoltaic DC-to-AC converters of described N platform photovoltaic DC-to-AC converter except First photovoltaic DC-to-AC converter is A, it is integer that the quantity of the input termination cell panel of described First photovoltaic DC-to-AC converter is at least A+1.A, and A>0.
In conjunction with first aspect, in the mode of the possible realization of the second, the negative pole of described First photovoltaic DC-to-AC converter connects the positive pole of M piece cell panel output, and the negative pole of M piece cell panel output connects the earth; Or the negative pole of the input of described First photovoltaic DC-to-AC converter connects the positive pole of M piece cell panel output by fuse, the negative pole of the output of M piece cell panel connects the earth.Or the negative pole of the input of described First photovoltaic DC-to-AC converter connects the positive pole of the output of M piece cell panel by switch, the negative pole of the output of M piece cell panel connects the earth.M is integer, and M>0.
Brief description of the drawings
According to embodiment and accompanying drawing, the present invention is described in further detail below.
Fig. 1 induces attenuator circuit schematic diagram for the present patent application embodiment mono-provides the potential electromotive force of a kind of anti-multi-machine parallel connection photovoltaic generating system circuit
Four kinds of earthing mode schematic diagrames of the regulator that Fig. 2 provides for the present patent application embodiment mono-
Two photovoltaic DC-to-AC converters that Fig. 3 provides for the present patent application embodiment mono-schematic diagram that is connected in parallel.
Embodiment
For the present invention is become apparent, hereby with preferred embodiment, and coordinate accompanying drawing to be described below in detail.
In the potential electromotive force induction attenuator circuit of the anti-multi-machine parallel connection photovoltaic generating system of one of the present invention and regulator, the parallel connection of N platform photovoltaic DC-to-AC converter, output AC electric current is also received same isolating transformer, by isolating transformer, alternating current is flowed to electrical network.By the neutral point of the input of isolating transformer being connect to the positive pole of the output of M piece cell panel, the minus earth of the output of M piece cell panel, and the quantity of connecing cell panel to the input of First photovoltaic DC-to-AC converter is greater than the quantity of the input termination cell panel of other photovoltaic DC-to-AC converters of the quantity of the input termination cell panel of removing First photovoltaic DC-to-AC converter in N platform, make like this cathode voltage of input of First photovoltaic DC-to-AC converter all larger than the cathode voltage of the input of other photovoltaic DC-to-AC converters of all, thereby avoid the negative pole of the input of photovoltaic DC-to-AC converter to produce negative pressure to the earth.Also solved simultaneously in photovoltaic DC-to-AC converter circuit pure the problem of Ground leakage current, heightened the energy output of photovoltaic generating system.
Below in conjunction with accompanying drawing to of the present invention mainly realize principle, specific implementation method with and the effect that reaches be described in detail.
Embodiment mono-
Please refer to Fig. 1, the embodiment of the present application provides a kind of multi-machine parallel connection circuit, and this circuit comprises:
The parallel connection of N platform photovoltaic DC-to-AC converter, the output of described N platform photovoltaic DC-to-AC converter connects the input of same isolating transformer, and the output of isolating transformer gets access to grid.The input of every photovoltaic DC-to-AC converter of described N platform photovoltaic DC-to-AC converter at least connects a cell panel, and described at least one cell panel is for to photovoltaic DC-to-AC converter, input provides voltage, and the output voltage of described at least one cell panel is identical.In described N platform photovoltaic DC-to-AC converter, only there is the negative pole of the input of First photovoltaic DC-to-AC converter to connect the positive pole of the output of regulator, the input of described voltage regulator gets access to grid, described voltage regulator is output as isolated high-voltage direct voltage, the output termination the earth of described regulator.Wherein N is integer, and N>1.
The quantity of the input termination cell panel of described First photovoltaic DC-to-AC converter is greater than in N platform photovoltaic DC-to-AC converter the quantity except the input termination cell panel of other photovoltaic DC-to-AC converters of First photovoltaic DC-to-AC converter.
Because the output voltage of every cell panel in the cell panel of every photovoltaic DC-to-AC converter input termination is identical, the input that is greater than other photovoltaic DC-to-AC converters due to the quantity of the input termination cell panel of First photovoltaic DC-to-AC converter connects the quantity of cell panel, so the bus Vbus1 of First photovoltaic DC-to-AC converter is larger than the busbar voltage Vbus2 of the input of second photovoltaic DC-to-AC converter of other photovoltaic DC-to-AC converter machines, be Vbus1>Vbus2. and the center line N1 of N photovoltaic DC-to-AC converter each photovoltaic DC-to-AC converter in parallel current potential in parallel equates, and the busbar voltage that the current potential of N1 line is 1/2nd adds the negative pole voltage to earth of the input of photovoltaic DC-to-AC converter.The neutral voltage Vn1=1/2Vbus1+PV1-of First photovoltaic DC-to-AC converter so, wherein PV1-is the input cathode voltage utterly of First photovoltaic DC-to-AC converter, the neutral voltage of second photovoltaic DC-to-AC converter is Vn2=1/2Vbus2+PV2-, and wherein PV2-is the input cathode voltage to earth of second photovoltaic DC-to-AC converter.Vn1=Vn2, have 1/2Vbus1+PV1-=1/2Vbus2+PV2-. because the input cathode of First photovoltaic DC-to-AC converter meets the output high-voltage DC power supply Udc of regulator, and Udc>0., PV1-=Udc.And Vbus1>Vbus2, so the input of the visible N platform of PV2->0. photovoltaic DC-to-AC converter connects high-voltage dc voltage over the ground, the negative pole of the input of all the other all photovoltaic DC-to-AC converters current potential over the ground is all greater than zero.And from avoided photovoltaic generating system cell panel high negative pressure over the ground, thereby there is anti-potential cell decay (PID) function, also avoided photovoltaic DC-to-AC converter leakage current over the ground simultaneously.
In specific implementation process, all the other photovoltaic DC-to-AC converters except First photovoltaic DC-to-AC converter in N platform photovoltaic DC-to-AC converter are referred to as to the second photovoltaic DC-to-AC converter once for convenience of description, the quantity of the second photovoltaic DC-to-AC converter is that the quantity of N-1. the second photovoltaic DC-to-AC converter input termination cell panel is A, A is integer, and the A>1. quantity of First photovoltaic DC-to-AC converter input termination cell panel is that A+B.B is integer, thereby and B>=1. ensures that First photovoltaic DC-to-AC converter input termination cell panel quantity is greater than the second photovoltaic DC-to-AC converter input termination cell panel quantity.
Please refer to Fig. 2, the negative pole of First photovoltaic DC-to-AC converter connects the positive pole of regulator output, and the negative pole of regulator connects the earth.Also the input cathode of First photovoltaic DC-to-AC converter can be received to the positive pole of the output of regulator by fuse, the output termination the earth of regulator.The positive pole that also input cathode of First photovoltaic DC-to-AC converter can be connect to regulator by switch, the negative pole of regulator connects the earth.Also the input cathode of First photovoltaic DC-to-AC converter can be connect to the output head anode of regulator by diode, the negative electrode of diode connects the negative pole of the input of First photovoltaic DC-to-AC converter, the anode of diode connects the positive pole of the output of regulator, and the negative pole of the output of regulator connects the earth.
Taking N=2 as example, circuit of the present invention is described in detail below.Please refer to Fig. 3, the input termination A piece cell panel of second photovoltaic DC-to-AC converter, the input termination A+1 piece cell panel of First photovoltaic DC-to-AC converter.The negative pole of the input of First photovoltaic DC-to-AC converter connects the output head anode of regulator, and the negative pole of output end of regulator connects the earth, and the output voltage of voltage regulator is Udc, Udc>0.The output of First photovoltaic DC-to-AC converter is in parallel and connect the input of isolating transformer in the output of second photovoltaic DC-to-AC converter, and the output of isolating transformer gets access to grid.The inside mid point above earth potential of First photovoltaic DC-to-AC converter is Vn1=1/2Vbus1+PV1-, and PV1-is the negative pole voltage to earth of the input of First photovoltaic DC-to-AC converter, PV1-=Udc.The inside mid point above earth potential of second photovoltaic DC-to-AC converter is that Vn2=1/2Vbus2+PV2-.PV2-is the voltage over the ground of negative pole of the input of second photovoltaic DC-to-AC converter.Because First photovoltaic DC-to-AC converter and second photovoltaic DC-to-AC converter are connected on same isolating transformer, therefore Vn1=Vn2=Vn, so, PV2-=1/2Vbus1-1/2Vus2+Udc, due to Vbus1>Vbus2, Udc>0, , PV2->0. visible, in 2 photovoltaic DC-to-AC converters, the input cathode of First photovoltaic DC-to-AC converter connects malleation voltage over the ground, , second photovoltaic DC-to-AC converter negative pole current potential is greater than zero, thereby avoid cell panel in photovoltaic generating system to form over the ground negative pressure, there is anti-potential electromotive force damping capacity, avoided photovoltaic DC-to-AC converter Ground leakage current simultaneously.
According to above-mentioned detailed description, those skilled in the art is according to the principle of above-described embodiment, and the clear circuit of knowing multi-machine parallel connection when N is arbitrary value, does not narrate one by one at this.
Claims (3)
1. the potential electromotive force induction of another anti-multi-machine parallel connection photovoltaic generating system attenuator circuit, is characterized in that, described circuit comprises:
The parallel connection of N platform photovoltaic DC-to-AC converter, the described output for N platform photovoltaic DC-to-AC converter all connects the input of same isolating transformer, and in described N platform photovoltaic DC-to-AC converter, every photovoltaic DC-to-AC converter input connects at least one cell panel; Described at least one cell panel provides input voltage for photovoltaic DC-to-AC converter, in described at least one cell panel, the output voltage of every cell panel is identical, in a described N photovoltaic DC-to-AC converter, only have the input cathode of First photovoltaic DC-to-AC converter to connect the positive pole of M piece cell panel, the negative pole of M piece cell panel connects the earth; Wherein N is integer, N>=2; M is integer, and M>0;
Other all inputs that the quantity of the input termination cell panel of described First photovoltaic DC-to-AC converter is greater than in described N platform inverter connect cell panel quantity.
2. circuit as claimed in claim 1, it is characterized in that, in described N platform inverter, the quantity of the photovoltaic DC-to-AC converter input termination cell panel except First photovoltaic DC-to-AC converter is A, the minimum number of the input termination cell panel of described First photovoltaic DC-to-AC converter is A+1, wherein A is integer, A>0.
3. circuit as claimed in claim 1, is characterized in that, the input cathode of described First photovoltaic DC-to-AC converter connects the output head anode of M piece cell panel, and the negative pole of M piece cell panel connects the earth; Or the input cathode of described First photovoltaic DC-to-AC converter connects the output head anode of M piece cell panel by fuse, the negative pole of output end of M piece cell panel connects the earth; Or the input cathode of described First photovoltaic DC-to-AC converter connects the input of switch, the output cathode of the output termination M piece cell panel of switch, the negative pole of M piece cell panel output connects the earth.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410413934.8A CN104201714A (en) | 2014-08-21 | 2014-08-21 | Another circuit for resisting potential-induced degradation of multi-parallel photovoltaic power generation system |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201410413934.8A CN104201714A (en) | 2014-08-21 | 2014-08-21 | Another circuit for resisting potential-induced degradation of multi-parallel photovoltaic power generation system |
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| CN104201714A true CN104201714A (en) | 2014-12-10 |
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| CN203166494U (en) * | 2013-03-26 | 2013-08-28 | 阳光电源（上海）有限公司 | Device for solving potential induced degradation |
| CN203218893U (en) * | 2013-04-24 | 2013-09-25 | 阳光电源（上海）有限公司 | Device for solving potential induction attenuation |
| CN103475271A (en) * | 2013-09-24 | 2013-12-25 | 深圳市禾望电气有限公司 | Photovoltaic power generation system and control method |
| CN103701150A (en) * | 2013-12-26 | 2014-04-02 | 华为技术有限公司 | Multi-unit parallel circuit, power supply system and voltage regulation method |
| CN103944502A (en) * | 2014-05-09 | 2014-07-23 | 阳光电源股份有限公司 | Anti-potential potential induction decay photovoltaic power generation system, photovoltaic module and inverter |
| CN204258330U (en) * | 2014-08-21 | 2015-04-08 | 山亿新能源股份有限公司 | The potential potential induction attenuation circuit of a kind of anti-multi-machine parallel connection photovoltaic generating system |
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2014
- 2014-08-21 CN CN201410413934.8A patent/CN104201714A/en active Pending
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102273039A (en) * | 2008-11-07 | 2011-12-07 | 丹佛斯太阳能变极器有限公司 | Photovoltaic power plant having an offset voltage source controlling the DC potential at the inverter output |
| CN203166494U (en) * | 2013-03-26 | 2013-08-28 | 阳光电源（上海）有限公司 | Device for solving potential induced degradation |
| CN203218893U (en) * | 2013-04-24 | 2013-09-25 | 阳光电源（上海）有限公司 | Device for solving potential induction attenuation |
| CN103475271A (en) * | 2013-09-24 | 2013-12-25 | 深圳市禾望电气有限公司 | Photovoltaic power generation system and control method |
| CN103701150A (en) * | 2013-12-26 | 2014-04-02 | 华为技术有限公司 | Multi-unit parallel circuit, power supply system and voltage regulation method |
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Application publication date: 20141210 |