CN201774475U - Topological structure for transformer-free solar inverter based on MMC - Google Patents
Topological structure for transformer-free solar inverter based on MMC Download PDFInfo
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- CN201774475U CN201774475U CN2010202679866U CN201020267986U CN201774475U CN 201774475 U CN201774475 U CN 201774475U CN 2010202679866 U CN2010202679866 U CN 2010202679866U CN 201020267986 U CN201020267986 U CN 201020267986U CN 201774475 U CN201774475 U CN 201774475U
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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 utility model relates to a topological structure for a transformer-free solar inverter based on an MMC, comprising a photocell array, a direct current conversion circuit, and an inverter consisting of a plurality of standard power units. The direct current voltage generated by the photocell array is converted into stable direct current voltage by the direct current conversion circuit and is subsequently used as direct current side voltage of each standard power unit in the inverter; and a plurality of standard power units can output reversibly and realize synthesis of three-phase alternate current voltage by serial connection, thus directly reaching the aims of high-voltage output and shunting in power network. The topological structure has the advantages that the transformer at the shunting side of the photovoltaic generating system is not needed, the high-voltage output is realized by adopting the way of superposing a plurality of standard power units; and the topological structure has low cost, the space is saved, the structure is simple and the response speed is quick.
Description
Technical field
The present invention relates to a kind of transless solar inverter topological structure based on MMC (Modular Multilevel Converter) modular multilevel inverter.
Background technology
In the epoch of current energy scarcity, photovoltaic generation is generally approved as regenerative resource and is greatly developed.China is backward relatively to the exploitation of luminous energy, and technology is in ascent stage, and the area of China is big, and solar energy year, amount of radiation was above 600kJ/cm
2, the solar energy that the annual face of land absorbs is equivalent to the energy of 17,000,000,000,000 tons of standard coals, therefore has good development prospect.
Photocell is the main devices that luminous energy is converted into electric energy.The photovoltaic cell arrays that photovoltaic generating system usually adopts some photocells to form, with reach combining inverter than high input voltage.
Solar inverter can be described as photovoltaic DC-to-AC converter again, is the conversion equipment that luminous energy is converted into electric energy.Solar inverter of the prior art is that the direct voltage that array is synthetic is reverse into three-phase alternating current, sends into electrical network through behind the transformer, has the design of transformer, make equipment investment big, take up an area of many, the cost height, the production cycle is long.
Summary of the invention
The purpose of this invention is to provide a kind of transless solar inverter topological structure based on MMC, this topological structure need not be provided with the be incorporated into the power networks transformer of side of photovoltaic generating system, adopts the stacking pattern of a plurality of calibration powers unit, realizes high pressure output; Cost is low, saves the space, and simple in structure, reaction speed is fast.
For achieving the above object, the present invention is achieved through the following technical solutions:
A kind of transless solar inverter topological structure based on MMC, the inverter that comprises photovoltaic cell arrays, DC transfer circuit, constitutes by a plurality of calibration powers unit, the direct voltage that photovoltaic cell arrays produces, after DC transfer circuit is transformed to the galvanic current pressure, as the dc voltage of each calibration power unit in the inverter; The inversion output of a plurality of calibration powers unit realizes the synthetic of three-phase alternating voltage through series connection, directly reaches high pressure output, is connected to the grid.
The power cell of inverter adopts the MMC unit as the calibration power unit, and the calibration power unit adopts half-bridge structure, two IGBT series connection up and down, dc capacitor in parallel again; Each calibration power unit is equipped with solar panel and DC transfer circuit, provides direct voltage by solar panel, is converted to galvanic current through DC transfer circuit and presses.
Inverter is a three-phase, whenever is made up of even number n calibration power unit, is divided into two groups up and down, and every group calibration power unit number is n/2, and output phase voltage level ladder number is n/2+1, and line voltage level number is n+1; The output of every phase is the midpoint of two standard sets power cell up and down, and between output and the every group of unit to be coupled or non-coupling inductance is connected.
Compared with prior art, the invention has the beneficial effects as follows:
1, the transless configuration makes equipment cost reduce by 1/2.
2, the transless configuration makes equipment volume reduce 1/2.
3, the transless configuration makes weight of equipment reduce 1/2.
4, the transless configuration makes the device fabrication cycle reduce 1/2.
5, the transless configuration has saved the structure and the space of carrying transformer.
6, the transless configuration has saved the high-tension cable that connects transformer.
7, the transless configuration makes the transportation convenience degree strengthen greatly.
8, adopt novel MMC calibration power unit, control strategy is simple and reliable.
Description of drawings
Fig. 1 is the topological structure schematic diagram of solar inverter;
Fig. 2 is the calibration power cell schematics of solar inverter;
Fig. 3-the 1st, power cell output state are the current direction figure of 0 state;
Fig. 3-the 2nd, power cell output state are the current direction figure of 0 state;
Fig. 4-the 1st, power cell output state are the current direction figure of 1 state;
Fig. 4-the 2nd, power cell output state are the current direction figure of 1 state.
Embodiment
See Fig. 1, a kind of transless solar inverter topological structure based on MMC, the inverter that comprises photovoltaic cell arrays, DC transfer circuit, constitutes by a plurality of calibration powers unit, the direct voltage that photovoltaic cell arrays produces, after DC transfer circuit is transformed to the galvanic current pressure, dc voltage as each calibration power unit in the inverter, by conducting and the shutoff of controlling each power cell switching device, realize the synthetic of A, B, C three-phase alternating voltage, directly reach high pressure output, directly be connected to the grid without transformer.This topology is based on the half-bridge serial connection technology, and the power cell type of employing is modular multilevel modular multilevel converter, is called MMC calibration power unit, is half-bridge structure.Can directly reach high pressure output, directly be connected to the grid, not need transformer, make cost reduce greatly, saved blower fan, the relevant high-tension cable of transformer has been saved in the structure and the space of carrying transformer, compact conformation, control simple and direct, for solar power generation provides a kind of new topologies.
See Fig. 2, the calibration power unit of inverter adopts half-bridge structure, is made up of two switching device IGBT and dc bus capacitor C, and IGBT1 and IGBT2 are in series, again and with dc capacitor C, and IGBT1 and IGBT2 reversal connection diode D1 of parallel connection respectively, D2.The common port of IGBT1 and IGBT2, the common port of capacitor C and IGBT2 link to each other with other unit as the output of each unit.Each calibration power unit is equipped with solar panel to carry out photovoltaic generation direct voltage is provided, and to adopt DC transfer circuit to be transformed to be that galvanic current is pressed.
Inverter is a three-phase, whenever is made up of even number n calibration power unit, is divided into two groups up and down, and every group calibration power unit number is n/2, and output phase voltage level ladder number is n/2+1, and line voltage level number is n+1; The output of every phase is the midpoint of two standard sets power cell up and down, and between output and the every group of unit to be coupled or non-coupling inductance L is connected.The inverter direct voltage that the unit DC side is synthetic is modulated into the three-phase voltage of interchange, by three output outputs, directly is connected to the grid.Every group calibration power unit number of inverter is called inverter progression, and the actual conditions that the several certificates of inverter stage are concrete need be determined.
The grid voltage of control IGBT makes its conducting or shutoff, can make the unit have different circuit states.Definition IGBT1 turn-offs, and the IGBT2 conducting is 0 state of unit, and this moment, electric current can be crossed (seeing Fig. 3-1) through the IGBT2 positive flow, also can cross (seeing Fig. 3-2) through parallel diode D2 reverse flow.Definition IGBT1 conducting, IGBT2 turn-offs and be 1 state of unit, the electric current diode D1 (seeing Fig. 4-2) that can flow through, and this moment, electric capacity charged; The IGBT1 (seeing Fig. 4-1) that also can flow through, this moment capacitor discharge.
If frequency converter progression is selected suitably, frequency converter output voltage can reach the electrical network rank, and frequency converter will send voltage waveform with synchronized according to line voltage, generate electricity by way of merging two or more grid systems.
The array structure of photovoltaic cell can be concentrated, serial type, form such as many trails are medium-sized.The step-up transformer that is not incorporated into the power networks does not have blower fan, high-tension cable, the auxiliary circuit relevant with transformer, the structure and the space that do not need to carry transformer yet.Every phase upper and lower bridge arm is linked to each other by the buffering reactance, and this reactance can be coupling reactance or non-coupling reactance.
Claims (4)
1. transless solar inverter topological structure based on MMC, it is characterized in that, the inverter that comprises photovoltaic cell arrays, DC transfer circuit, constitutes by a plurality of calibration powers unit, the direct voltage that photovoltaic cell arrays produces, after DC transfer circuit is transformed to the galvanic current pressure, as the dc voltage of each calibration power unit in the inverter; The inversion output of a plurality of calibration powers unit realizes the synthetic of three-phase alternating voltage through series connection, directly reaches high pressure output, is connected to the grid.
2. a kind of transless solar inverter topological structure according to claim 1 based on MMC, it is characterized in that, the power cell of inverter adopts the MMC unit as the calibration power unit, the calibration power unit adopts half-bridge structure, two IGBT series connection up and down, dc capacitor in parallel again; Each calibration power unit is equipped with solar panel and DC transfer circuit, provides direct voltage by solar panel, is converted to galvanic current through DC transfer circuit and presses.
3. a kind of transless solar inverter topological structure according to claim 2 based on MMC, it is characterized in that, inverter is a three-phase, whenever, form by even number n calibration power unit, be divided into two groups up and down, every group calibration power unit number is n/2, and output phase voltage level ladder number is n/2+1, and line voltage level number is n+1; The output of every phase is the midpoint of two standard sets power cell up and down, and between output and the every group of unit to be coupled or non-coupling inductance is connected.
4. a kind of transless solar inverter topological structure based on MMC according to claim 1 is characterized in that, described photovoltaic cell arrays adopts solar panel to constitute.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2010202679866U CN201774475U (en) | 2010-07-22 | 2010-07-22 | Topological structure for transformer-free solar inverter based on MMC |
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| CN2010202679866U CN201774475U (en) | 2010-07-22 | 2010-07-22 | Topological structure for transformer-free solar inverter based on MMC |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103825487A (en) * | 2014-02-28 | 2014-05-28 | 华南理工大学 | SiC high-voltage switch and silicon IGBT mixed type three-phase four-wire high-voltage converter |
| CN104167760A (en) * | 2014-07-28 | 2014-11-26 | 湖南大学 | Modularization multi-level photovoltaic grid connected system and control method thereof |
| CN105680686A (en) * | 2015-08-03 | 2016-06-15 | 许昌开普电气研究院 | MMC-based novel topological structure for photovoltaic power generation system |
| TWI721621B (en) * | 2019-10-29 | 2021-03-11 | 財團法人工業技術研究院 | Three-phase expandable ac system based on battery reconfiguration and control method thereof |
-
2010
- 2010-07-22 CN CN2010202679866U patent/CN201774475U/en not_active Expired - Fee Related
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103825487A (en) * | 2014-02-28 | 2014-05-28 | 华南理工大学 | SiC high-voltage switch and silicon IGBT mixed type three-phase four-wire high-voltage converter |
| CN103825487B (en) * | 2014-02-28 | 2017-01-04 | 华南理工大学 | SiC high-voltage switch gear and silicon IGBT hybrid three-phase and four-line high tension transformer |
| CN104167760A (en) * | 2014-07-28 | 2014-11-26 | 湖南大学 | Modularization multi-level photovoltaic grid connected system and control method thereof |
| CN104167760B (en) * | 2014-07-28 | 2016-03-30 | 湖南大学 | A kind of modular multilevel photovoltaic parallel in system and control method thereof |
| CN105680686A (en) * | 2015-08-03 | 2016-06-15 | 许昌开普电气研究院 | MMC-based novel topological structure for photovoltaic power generation system |
| TWI721621B (en) * | 2019-10-29 | 2021-03-11 | 財團法人工業技術研究院 | Three-phase expandable ac system based on battery reconfiguration and control method thereof |
| US11424620B2 (en) | 2019-10-29 | 2022-08-23 | Industrial Technology Research Institute | Three-phase expandable AC system based on battery reconfiguration and control method thereof |
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Granted publication date: 20110323 Termination date: 20130722 |