CN203445626U - Solar power generation device - Google Patents
Solar power generation device Download PDFInfo
- Publication number
- CN203445626U CN203445626U CN201320127724.3U CN201320127724U CN203445626U CN 203445626 U CN203445626 U CN 203445626U CN 201320127724 U CN201320127724 U CN 201320127724U CN 203445626 U CN203445626 U CN 203445626U
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- China
- Prior art keywords
- solar power
- inverter
- transformer
- power plant
- photovoltaic
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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
Discloses is a solar power generation device (11) which is used for generating electric power that is to be feed to a multiphase power grid (NE). The solar power generation device comprises multiple photovoltaic strings (13a, 13b, 13c), each of which is linked to a different phase (L1, L2, L3) via a corresponding inverter (15), wherein the phase is connected to a primary side of a power supply transformer (14); each inverter (15) is used for converting the direct-current voltage generated through photovoltaic modules (12) into alternating-current voltage consistent with that of the power grid; and the power supply transformer (14) is equipped with a neutral conductor (N) and a grounding terminal (PE). Especially, in the case of thin film modules, the solar power generation device (11) is improved to improve the life span of the photovoltaic modules, thereby allowing the inverters to obtain high conversion efficiency at low wiring cost. The method adopted to realize such an aim is that an additional direct-current voltage source (6) is inserted between the neutral conductor (N) and the ground (PE) or between one of the phases (L1, L2, L3) and the ground (PE), so that the electric potential of the photovoltaic strings (13a, 13b, 13c) is transferred and the bias voltage is set not to be zero volt.
Description
Technical field
The present invention relates to a kind of solar power plant, described solar power plant comprises: for generation of a plurality of photovoltaic modules of the electric power in polyphase electrical system to be fed to; Some photovoltaic strings of distributing to out of phase, described photovoltaic string is connected to the primary side of power transformer; And at least one inverter, described inverter converts for the direct voltage that photovoltaic module is produced the ac grid voltage consistent with electrical network being provided to, and power transformer is provided with neutral conductor and earth terminal or is only provided with earth terminal.
Background technology
Solar facilities also referred to as solar power plant comprises a plurality of solar energy modules and one or more inverter.The photovoltaic module series connection of playing generator effect connects to form so-called string.Some strings can be connected in parallel.Inverter be configured to directly or via associating power transformer to electrical network feed.In principle, can adopt single-phase or polyphase inverter, especially three-phase inverter.
Known single-phase inverter is arranged to any single-phase middle generation feed at polyphase source transformer.For each phase, all there is at least one inverter.Inverter is connected to each mutually or conductor L1, L2, L3 through switch (particularly contactor), and is therefore connected to the primary side of transformer.
In primary side, transformer coil can Y-connection.Then mid point can be connected to neutral conductor " N ".Neutral conductor N also can be connected to the earth (PE).The coil of primary side preferably connects and composes with triangle.
If use polyphase inverter (being more specifically three-phase inverter), the efferent of inverter is connected to conductor L1, L2, L3 via contactor.
Some photovoltaic modules (especially thin-film module) preferably operate in the mode of the specific orientation of the electric field strength avoided at battery place.Otherwise premature aging may occur these modules, thereby cause the life-span shorter.
A kind of known scheme is for example, by a terminal (negative terminal) ground connection of photovoltaic generator.As a result, at the battery place of module, only produce the voltage with predetermined polarity of ground.For example, but the ground connection of module makes to use the transformerless type inverter of current separation inverter (inverter that comprises transformer) or particular topology.Two kinds of inverters all produce corresponding polarity input voltage in inside is so that can be to electrical network feed.This causes the conversion efficiency of these inverters to reduce.
Summary of the invention
An object of the present invention is to improve as follows the solar power plant of the above-mentioned type: at generator terminal place, provide the voltage of predetermined polarity to improve the long-lasting of photovoltaic module, particularly, the in the situation that of thin-film module, still allow inverter to obtain high conversion efficiency under low wiring cost.
According to a kind of modification, the solution of above-mentioned purpose is: between neutral conductor and the earth, insert additional direct voltage source, make the electromotive force of photovoltaic string shift and in the mode changing, bias voltage be arranged to zero volt.
According to another kind of modification, between a kind of phase place and the earth, insert therein additional direct voltage source, make the electromotive force of photovoltaic string shift and in the mode changing, bias voltage is set as to zero volt.
Therefore, the invention provides a kind of for via power transformer by the feeding power producing by a plurality of photovoltaic strings the solar power plant to polyphase electrical system (NE), described power transformer comprises the have neutral conductor primary coil of (N), secondary coil and earth terminal (PE), each in wherein said a plurality of photovoltaic string is all connected to corresponding inverter and described corresponding inverter again through corresponding phase (L1, L2, L3) be connected to described primary coil, it is characterized in that, direct voltage source is connected to described neutral conductor (N) and is connected to described earth terminal (PE) by the second connecting terminals by the first terminal, by the bias voltage of non-zero, shift thus the electromotive force of described photovoltaic string.
In addition, the present invention also provide a kind of for via power transformer by the feeding power producing by a plurality of photovoltaic strings the solar power plant to polyphase electrical system (NE), described power transformer comprises having primary coil, secondary coil and earth terminal (PE), each in wherein said a plurality of photovoltaic string is connected to corresponding inverter and described corresponding inverter again through corresponding phase (L1, L2, L3) be connected to described primary coil, it is characterized in that, direct voltage source is connected to described one (L1 in mutually by the first terminal, L2, L3) and by the second connecting terminals be connected to described earth terminal (PE), by the bias voltage of non-zero, shift thus the electromotive force of described photovoltaic string.
Thereby the solution of the present invention provides the unfavorable orientation that prevents electric field strength to avoid the advantage of the premature aging of module.
A concrete advantage of the present invention is to adopt the photovoltaic generator of preferred ground connection operation.And, circuit arrangement of the present invention can with all inverter topology couplings that itself need in the main equipment of power transformer.Therefore, do not need to exist special inverter.
According to the present invention, obtain a kind of solar facilities with at least one power transformer, additional direct voltage source inserts between neutral conductor (N) and the earth (PE), the electromotive force of a described terminal of photovoltaic string is set to and is not zero volt, is preferably greater than the electromotive force of zero volt.But, this electromotive force can be also negative voltage.In magnitude and polarity, bias voltage is with respect to regulate the electromotive force of photovoltaic string such as reference potentials such as ground potential.
And the present invention is not in the situation that use electric current isolated inverter or the transformerless type inverter of particular electrical circuit topology has solved problem with grounding.
Use do not have neutral conductor, to the three-phase inverter arrangement of electrical network feed, direct voltage source can be inserted between the one and PE in three-phase L1, L2, L3.Use the three-phase inverter arrangement of being combined with the electrical network that comprises neutral conductor, direct voltage source can be connected between neutral conductor and PE.The mid point of transformer is connected to neutral conductor.Equally, power transformer can be polyphase transformer.
Narrate in the dependent claims other preferred embodiment of the present invention.
In a preferred embodiment of the present invention, the current monitor that direct voltage source is set carrys out detection of ground faults.This permission additionally monitors such as earth faults such as defective insulations with very little spending aspect circuit, both can be simultaneously for having promoted electromotive force and having measured electric current because lead to the same current path of PE.
By bias supply mid point correspondingly, can obtain the unipolar bias voltage of all photovoltaic cells of generator, even if they are through transformerless type Inverter Fed.Therefore, utilize such as thin-film module or there is the induction photovoltaic modules such as module of amorphous state battery, also can in high-performance photovoltaic equipment, use efficiently transformerless type inverter.Therefore, advantageously described a plurality of photovoltaic string comprises thin-film module and each inverter is embodied as to transformerless type inverter.
In another preferred embodiment of the present invention, each all uses an inverter mutually.When generating equipment energy output is high, it is useful using some unidirectional inverters.Unidirectional inverter does not usually possess electric current isolation.Inverter arrangements become make polyphase transformer each mutually in generation feed.Each all arranges at least one inverter mutually.These inverters can be connected to N conductor and/or PE conductor, and making especially in the situation that do not possess the inverter of electric current isolation, does not need in addition by module ground connection, because they are via inverter ground connection.
In addition, each inverter is connected to described transformer via respective switch.If connect another power transformer that is positioned at inverter case outside, a multipole switch or some switches can be connected in the access path between inverter and power transformer.
By control switch, current flowing can be for example the in the situation that of earth fault or be interrupted in all other cases.Advantageously, at least one contactor is as described switch, and therefore each inverter is connected to transformer through switch (especially through contactor).
In addition, the primary coil of described power transformer can arrange in the mode of Y-connection, and mid point is connected to described neutral conductor (N).
In addition, the mode that the primary coil of described power transformer can connect with triangle arrange, described transformer is implemented as is not with neutral conductor (N).
Distinguish inverter arrangements structure and whether at its outlet side, there is neutral conductor.If there is no neutral conductor can adopt not with neutral conductor and have the transformer that triangle connects in primary side.Therefore, otherwise the primary side Y-connection of transformer, the mid point of transformer is connected to neutral conductor, or alternately, the primary side of transformer has triangle and connects, and transformer is implemented as is not with neutral conductor.Advantageously, the coil of the primary side of transformer connects and composes with triangle.
Accompanying drawing explanation
Below with reference to accompanying drawing, introduce in more detail exemplary embodiment, wherein will describe other the favourable scheme of development and implementation and advantage thereof of the present invention.
In the accompanying drawings:
Fig. 1 illustrates the diagram of the first embodiment of solar power plant of the present invention, and
Fig. 2 illustrates the diagram of the second embodiment of solar power plant of the present invention.
Embodiment
Fig. 1 illustrates the first embodiment of solar power plant 11.Solar power plant 11 comprises for generation of a plurality of photovoltaic module 12(that wait to be fed to the electric power in heterogeneous (especially three-phase) electrical network NE especially thin-film module).Some photovoltaic string 13a, 13b, 13c, wherein each is connected from different one through corresponding inverter 15, is connected to the primary side of power transformer 14.A plurality of inverter 15(are transformerless type inverter especially) convert the direct voltage producing by photovoltaic string 13a, 13b, 13c to the supply voltage consistent with electrical network.Inverter 15 can comprise and boosting and/or step-down controller, bridgt circuit, pulse width control and/or MPP control.Power transformer 14 is provided with neutral conductor N and earth terminal PE.
Three single-phase inverters 15 be arranged so that feed occurs in three phase mains transformer 14 each mutually in.Each all arranges at least one inverter 15 mutually.
According to the present invention, additional direct voltage source 16 is inserted in one (as shown in Figure 2) in phase place L1, L2 and L3 or neutral conductor N(as shown in fig. 1) and the earth PE between, the electromotive force of photovoltaic string 13a, 13b, 13c is shifted and the negative terminal of photovoltaic string 13a, 13b, 13c and the bias voltage between the earth PE are set to and are not zero volt, be particularly greater than zero volt.By the corresponding bias voltage of electrical network mid point, can obtain the unipolar bias voltage of all photovoltaic cells, even if use transformerless type inverter.
Current monitor for detection of earth fault can be arranged in the circuit paths of direct voltage source 16.In insulation or earth fault in the situation that, can starting contactor 17 to interrupt the electrical connection between inverter 15 and power transformer 14.Interruption between electrical network NE and transformer 14 is also possible and is expected.Therefore, each inverter 15 is connected to transformer 14 through switch.
In a kind of modification, a described primary side of transformer 14 is Y-connections, and the mid point of transformer 14 is connected to neutral conductor N.
In another kind of modification, Transformer structure becomes not have neutral conductor N, as shown in Figure 2.The mode that the primary side of transformer can triangle connects is arranged.According to the present invention, direct voltage source 16 can be inserted between the one and the earth PE in phase place L1, L2, L3, the electromotive force of photovoltaic string 13a, 13b, 13c is shifted and the negative terminal of photovoltaic string 13a, 13b, 13c and the bias voltage between the earth PE are set to and are greater than zero volt.In two kinds of modification, the mode that the coil of the primary side of transformer 14 connects with triangle is arranged.
Also can adopt inverter efferent through switch or one or several contactor, to be connected to the three-phase inverter of conductor L1, L2, L3.
List of numerals
11 solar power plants
12 photovoltaic modules
13a, 13b, 13c photovoltaic string
14 power transformers
15 inverters
16 direct voltage sources
17 contactors
L1, L2, L3 conductor
PE the earth
N neutral conductor
NE electrical network
Claims (16)
1. one kind for will be by a plurality of photovoltaic string (13a via power transformer (14), 13b, feeding power 13c) producing is to the solar power plant (11) in polyphase electrical system (NE), described power transformer (14) comprises have neutral conductor primary coil, secondary coil and the earth terminal (PE) of (N), wherein said a plurality of photovoltaic string (13a, 13b, each 13c) is all connected to corresponding inverter (15) and described corresponding inverter (15) again through corresponding phase (L1, L2, L3) be connected to described primary coil
It is characterized in that
Direct voltage source (16) is connected to described neutral conductor (N) and is connected to described earth terminal (PE) by the second connecting terminals by the first terminal, shifts thus the electromotive force of described photovoltaic string (13a, 13b, 13c) by the bias voltage of non-zero.
2. solar power plant according to claim 1, wherein, described solar power plant also comprises the current monitor of described direct voltage source (16), it is for detection of earth fault.
3. solar power plant according to claim 1, wherein, described a plurality of photovoltaic strings (13a, 13b, 13c) comprise thin-film module.
4. solar power plant according to claim 1, wherein, each inverter (15) is implemented as transformerless type inverter.
5. solar power plant according to claim 1, wherein, each inverter (15) is connected to described transformer (14) via respective switch.
6. solar power plant according to claim 5, wherein, at least one contactor (17) is as described switch.
7. solar power plant according to claim 1, wherein, the described primary coil of described power transformer (14) arranges in the mode of Y-connection, mid point is connected to described neutral conductor (N).
8. solar power plant according to claim 1, wherein, the mode that the described secondary coil of described power transformer (14) connects with triangle is arranged.
9. one kind for will be by a plurality of photovoltaic string (13a via power transformer (14), 13b, feeding power 13c) producing is to the solar power plant (11) in polyphase electrical system (NE), described power transformer (14) comprise there is primary coil, secondary coil and earth terminal (PE), wherein said a plurality of photovoltaic string (13a, 13b, each 13c) is connected to corresponding inverter (15) and described corresponding inverter (15) again through corresponding phase (L1, L2, L3) be connected to described primary coil
It is characterized in that
Direct voltage source (16) is connected to described one (L1 in mutually by the first terminal, L2, L3) and be connected to described earth terminal (PE) by the second connecting terminals, the bias voltage by non-zero shifts described photovoltaic string (13a thus, 13b, 13c) electromotive force.
10. solar power plant according to claim 9, wherein, described solar power plant also comprises the current monitor of described direct voltage source (16), it is for detection of earth fault.
11. solar power plants according to claim 9, wherein, described a plurality of photovoltaic strings (13a, 13b, 13c) comprise thin-film module.
12. solar power plants according to claim 9, wherein, each inverter (15) is implemented as transformerless type inverter.
13. solar power plants according to claim 9, wherein, each inverter (15) is connected to described transformer (14) via respective switch.
14. solar power plants according to claim 13, wherein, at least one contactor (17) is as described switch.
15. solar power plants according to claim 9, wherein, the mode that the described primary coil of described power transformer (14) connects with triangle arranges, described transformer (14) is implemented as is not with neutral conductor (N).
16. solar power plants according to claim 9, wherein, the mode that the described secondary coil of described power transformer (14) connects with triangle is arranged.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320127724.3U CN203445626U (en) | 2013-03-20 | 2013-03-20 | Solar power generation device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201320127724.3U CN203445626U (en) | 2013-03-20 | 2013-03-20 | Solar power generation device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN203445626U true CN203445626U (en) | 2014-02-19 |
Family
ID=50096644
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201320127724.3U Expired - Lifetime CN203445626U (en) | 2013-03-20 | 2013-03-20 | Solar power generation device |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN203445626U (en) |
-
2013
- 2013-03-20 CN CN201320127724.3U patent/CN203445626U/en not_active Expired - Lifetime
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term |
Granted publication date: 20140219 |
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| CX01 | Expiry of patent term |