CN204794878U - Current sample photovoltaic power generation system - Google Patents
Current sample photovoltaic power generation system Download PDFInfo
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- CN204794878U CN204794878U CN201520184663.3U CN201520184663U CN204794878U CN 204794878 U CN204794878 U CN 204794878U CN 201520184663 U CN201520184663 U CN 201520184663U CN 204794878 U CN204794878 U CN 204794878U
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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
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Abstract
The utility model discloses a current sample photovoltaic power generation system, including a plurality of photovoltaic module, a plurality of DC -DC converter and the converter that is incorporated into the power networks, photovoltaic module's output is parallelly connected with the input of corresponding DC -DC converter, and every photovoltaic module's outlet side is established ties, forms direct current generating set cluster from this, in the direct current generating set cluster output after photovoltaic module establishes ties forms the high voltage direct current generating line, in the direct current generating set cluster the direct high voltage direct current generating line with the rear end of output of DC -DC converter is parallelly connected, the high voltage direct current generating line is connected to outside electric wire netting through grid -connected inverter. The utility model discloses a photovoltaic power generation system utensil system efficiency is high, and self loss is low, no longer has intrinsic power conversion loss, and the comprehensive conversion efficiency of system's full load within range can reach more than 99.5%.
Description
Technical field
The utility model relates to a kind of current sample photovoltaic generating system.
Background technology
At present, develop and utilize the novel energy such as solar energy, thermoelectricity generation technology to be the Important Action of tackling the energy and environmental crisis.Because generation of electricity by new energy equipment cost is high and energy conversion efficiency is low, greatly add cost of electricity-generating, limit the promotion and application of generation of electricity by new energy technology.For solar photovoltaic generation system, application background of the present invention is described below.Parallel network power generation is that topmost mode applied by solar power generation, and according to statistics, the photovoltaic power generation equipment installed capacity of the whole world more than 90% is grid-connected application, this is because the relatively independent photovoltaic system of grid-connected application has the advantages such as cost is low and non-maintaining.Grid-connected photovoltaic system is divided into centralized and distributed two types.Distributed MPPT system can ensure that each photovoltaic module is operated in respective maximum power point, the voltage that solution exists when the direct connection in series-parallel of assembly connects unless each or current coupling, eliminate characteristic between photovoltaic module inconsistent or environmental condition is inconsistent time because affect the energy output caused each other to reduce problem, improve systems generate electricity efficiency, improve system reliability high simultaneously, be thus subject to extensive concern.Present stage, distributed MPPT system was generally by series system access photovoltaic module rear end, the process of each MPPT system be coupled photovoltaic module overall power, so make each distributed MPPT system comparatively large from loss, caloric value is comparatively large, cost is higher, reliability also declines.Consider the feature of distributed power generation, its cost comparatively conventional power generation systems is enhanced, and therefore the energy output of distributed MPPT system and cost are very crucial problems.
In addition, conventional power generation systems in order to improve low-voltage power supply efficiency, reduce line current generally adopt boost type (BOOST) direct current (DC) supply power mode.Boost type (BOOST) direct current (DC) power supply produces short trouble when exporting; when output voltage is lower than input voltage; BOOST circuit function lost efficacy; input power is directly to grid short circuit; big current (high-power) system short-circuit protecting control difficulty is very large; cause the output stability of traditional electricity generation system poor, efficiency is low, reliability is not high.
Utility model content
The utility model object is that the defect existed for prior art provides a kind of current sample photovoltaic generating system.
The utility model for achieving the above object, adopts following technical scheme: a kind of current sample photovoltaic generating system, comprises multiple photovoltaic module, multiple DC-DC converter and a combining inverter; The output of described photovoltaic module is in parallel with the input of corresponding DC-DC converter, and the series connection of the outlet side of each described photovoltaic module, form DC generation group string thus; Output after described photovoltaic module series connection in described DC generation group string forms high voltage dc bus, the output of the described DC-DC converter in described DC generation group string is directly in parallel with the high voltage dc bus of rear end, and described high voltage dc bus is connected to external electrical network by combining inverter; Wherein, the output of described combining inverter is also connected to current sample feedback circuit, the output of described current sample feedback circuit is connected with PWM boost control circuit, and the output of described PWM boost control circuit is connected with the control input end of described DC-DC converter respectively.
The beneficial effects of the utility model: photovoltaic generating system tool system effectiveness of the present invention is high, and own loss is low, no longer have intrinsic power conversion loss, the comprehensive conversion efficiency in system full-load range can reach more than 99.5%.In addition, before system access to electrical network by current sample feedback circuit by precise acquisition direct current, and control DC-DC converter by PWM boost control circuit, ensure also to have an impact the reliability that system exports to the operation of system even if DC-DC converter loses efficacy.
Accompanying drawing explanation
Fig. 1 is circuit theory diagrams of the present utility model.
Fig. 2 is PWM boost control circuit fundamental diagram of the present utility model.
Embodiment
Shown in Fig. 1, Fig. 2, relate to a kind of current sample photovoltaic generating system, comprise multiple photovoltaic module 1, multiple DC-DC converter 2 and a combining inverter 3; The output of described photovoltaic module 1 is in parallel with the input of corresponding DC-DC converter 2, and the series connection of the outlet side of each described photovoltaic module 1, form DC generation group string 7 thus; Output after described photovoltaic module 1 series connection in described DC generation group string 7 forms high voltage dc bus, the output of the described DC-DC converter 2 in described DC generation group string 7 is directly in parallel with the high voltage dc bus of rear end, and described high voltage dc bus is connected to external electrical network 4 by combining inverter 3; Wherein, the output of described combining inverter 3 is also connected to current sample feedback circuit 5, the output of described current sample feedback circuit 5 is connected with PWM boost control circuit 6, and the output of described PWM boost control circuit 6 is connected with the control input end of described DC-DC converter 2 respectively.
Wherein, in order to what make whole photovoltaic system, there is better conversion efficiency, higher power factor and power density and higher reliability; Described PWM boost control circuit 6 in native system can adopt following technical scheme: it comprises the PWM controller 61 be connected with the output of current sample feedback circuit 5, the output of described PWM controller 61 is connected with signal synthesis circuit 62, the output of described signal synthesis circuit 62 is connected with driving switch electricity 63 tunnels, and the output of described driving switch circuit 63 is connected with the control input end of described DC-DC converter 2 by isolation filter circuit 64.
1) when system starts, DC-DC converter is MPPT to the Difference of Output Power of each photovoltaic module respectively, and power output is respectively p1=i1*u1, p2=i2*u2, pn=in*un, the Difference of Output Power Δ pn=pn-min{i1 of single photovoltaic module, i2 ... in}*un;
When in this step, DC-DC converter is MPPT to output power of photovoltaic module difference section, when DC-DC converter increases after voltage, if component integration power increases, voltage continues to be increased to till component integration power diminishes; When DC-DC converter reduces after voltage, if the increase of component integration power, voltage continues to be reduced to till component integration power diminishes;
(2) rear end combining inverter is MPPT to whole photovoltaic generating system, and power output is pbus1=min{i1,
i2…in}*ubus；
(3) DC-DC converter is by n output power of photovoltaic module discrepancy delta p1, Δ p2 ... Δ pn directly also
Enter back end DC bus, summation is pbus2=Δ P1+ Δ p2+ ... + Δ pn;
(4) the peak power output pmax=Pbus1+Pbus2 of whole photovoltaic generating system;
(5) when the output current of front end photovoltaic module is consistent, i.e. i1=i2=i3=...=in, Δ pn=pn-min{i1, i2 ... in}*un=0, rear end combining inverter does the power output of MPPT to photovoltaic generating system
Pbus1=in*ubus, DC-DC converter is by n block output power of photovoltaic module difference sum pbus2=Δ P1+ Δ p2+ ... + Δ pn=0 is directly incorporated into back end DC bus, and the peak power output of whole electricity generation system is pmax=Pbus1+pbus2=in*ubus;
(6) when front end photovoltaic module output current is inconsistent, i.e. i1 ≠ i2 ≠ i3 ≠ ... ≠ in, Δ pn=pn-min{i1, i2.。。In}*un ≠ 0, rear end combining inverter is the power output pbus1=min{i1 of MPPT to photovoltaic generating system, i2.。。In}*ubus, DC-DC converter is by n block output power of photovoltaic module difference sum pbus2=Δ p1+ Δ p2+ ... + Δ pn ﹥ 0 is directly incorporated into back end DC bus, the peak power output pmax=Pbus1+Pbus2=min{i1 of whole photovoltaic generating system, i2 ... in}*ubus+ Δ p1+ Δ p2+ ... + Δ pn;
(7) through the judgement of above step (5) and step (6), no matter whether the output current of a front end n photovoltaic module is variant, and whole electricity generation system always can obtain maximum power pmax and export.
(8) current sample feedback circuit is set before the output of combining inverter is linked into electrical network, by the direct current that this current sample feedback circuit precise acquisition combining inverter exports, and controlled the output of corresponding DC-DC converter by PWM boost control circuit, the reliability that the system that ensure that exports; Even if DC-DC converter lost efficacy and also can not have an impact to the operation of system like this.
From such scheme, photovoltaic generating system of the present utility model utilizes DC-DC converter and rear end combining inverter to be MPPT to the power output of single output power of photovoltaic module difference section and whole photovoltaic generating system respectively, single photovoltaic module power difference section can be directly incorporated into back end DC bus by DC-DC converter simultaneously, by the mutual cooperation of two kinds of MPPT functions, whole grid-connected power generation system is made to reach maximum power output.
In addition, because single output power of photovoltaic module difference section (accounting for 10% ~ 20% of overall power) is only MPPT by DC-DC converter, so its power grade is 10% ~ 20% of photovoltaic module, therefore caloric value is very little, volume weight is also greatly reduced, cost reduces, fundamentally improve the system effectiveness of grid-connected power generation system, reach the object improving energy output, reduce costs.
The foregoing is only preferred embodiment of the present utility model, not in order to limit the utility model, all within spirit of the present utility model and principle, any amendment done, equivalent replacement, improvement etc., all should be included within protection range of the present utility model.
Claims (1)
1. a current sample photovoltaic generating system, is characterized in that, comprises multiple photovoltaic module, multiple DC-DC converter and a combining inverter; The output of described photovoltaic module is in parallel with the input of corresponding DC-DC converter, and the series connection of the outlet side of each described photovoltaic module, form DC generation group string thus; Output after described photovoltaic module series connection in described DC generation group string forms high voltage dc bus, the output of the described DC-DC converter in described DC generation group string is directly in parallel with the high voltage dc bus of rear end, and described high voltage dc bus is connected to external electrical network by combining inverter; Wherein, the output of described combining inverter is also connected to current sample feedback circuit, the output of described current sample feedback circuit is connected with PWM boost control circuit, and the output of described PWM boost control circuit is connected with the control input end of described DC-DC converter respectively.
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| CN201520184663.3U CN204794878U (en) | 2015-03-30 | 2015-03-30 | Current sample photovoltaic power generation system |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107453403A (en) * | 2017-09-30 | 2017-12-08 | 阳光电源股份有限公司 | A kind of photovoltaic generating system and its control method |
| CN107884661A (en) * | 2017-10-18 | 2018-04-06 | 厦门科华恒盛股份有限公司 | A kind of method and apparatus for detecting photovoltaic DC-to-AC converter input wires mode |
| CN112117754A (en) * | 2020-08-11 | 2020-12-22 | 国网江苏省电力有限公司电力科学研究院 | Non-full-power photovoltaic conversion system |
| CN112332669A (en) * | 2020-11-11 | 2021-02-05 | 阳光电源股份有限公司 | MLPE photovoltaic system and photovoltaic string control method thereof |
-
2015
- 2015-03-30 CN CN201520184663.3U patent/CN204794878U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107453403A (en) * | 2017-09-30 | 2017-12-08 | 阳光电源股份有限公司 | A kind of photovoltaic generating system and its control method |
| CN107884661A (en) * | 2017-10-18 | 2018-04-06 | 厦门科华恒盛股份有限公司 | A kind of method and apparatus for detecting photovoltaic DC-to-AC converter input wires mode |
| CN107884661B (en) * | 2017-10-18 | 2020-07-03 | 科华恒盛股份有限公司 | Method and device for detecting input wiring mode of photovoltaic inverter |
| CN112117754A (en) * | 2020-08-11 | 2020-12-22 | 国网江苏省电力有限公司电力科学研究院 | Non-full-power photovoltaic conversion system |
| CN112332669A (en) * | 2020-11-11 | 2021-02-05 | 阳光电源股份有限公司 | MLPE photovoltaic system and photovoltaic string control method thereof |
| US11841724B2 (en) | 2020-11-11 | 2023-12-12 | Sungrow Power Supply Co., Ltd. | MLPE photovoltaic system and method for photovoltaic string control in MLPE photovoltaic system |
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| C14 | Grant of patent or utility model | ||
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| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20151118 Termination date: 20160330 |