CN202261071U - High-efficiency single-phase photovoltaic grid-connected inverter - Google Patents
High-efficiency single-phase photovoltaic grid-connected inverter Download PDFInfo
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- CN202261071U CN202261071U CN201120387329XU CN201120387329U CN202261071U CN 202261071 U CN202261071 U CN 202261071U CN 201120387329X U CN201120387329X U CN 201120387329XU CN 201120387329 U CN201120387329 U CN 201120387329U CN 202261071 U CN202261071 U CN 202261071U
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- switching tube
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- frequency switching
- switch pipe
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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 discloses a high-efficiency single-phase photovoltaic grid-connected inverter, which relates to the technical field of power electronics power conversion. The other end of an inductor (L2) is respectively connected with the anode of a fly-wheel diode (D2) and the grid electrode of a high-frequency switching tube (S2); the other end of a photovoltaic cell panel (PV) and the cathode of a capacitor (C1) are respectively connected with the emitting electrode of the high-frequency switching tube (S2) and the emitting electrode of a high-frequency switching tube (S4); the other end of an inductor (L1) is respectively connected with the anode of a fly-wheel diode (D1) and the grid electrode of the high-frequency switching tube (S4); and the other end of a relay (K2) is connected with the other end of a power grid. The phenomenon that large leakage current can be prevented from generating between the photovoltaic cell panel and the earth by controlling a single-phase photovoltaic grid-connected inverter without a transformer, so the leakage current is low, and the grid-connected requirement and the safety requirement are met; the control is relatively simple; the total efficiency is improved; and the highest efficiency of the topology structure of the high-efficiency single-phase photovoltaic grid-connected inverter can reach 98 percent.
Description
Technical field
The utility model relates to electric and electronic power converter technique field, is specifically related to efficient single-phase photovoltaic grid-connected inverter.
Background technology
Under the exhausted day by day background of the energy, the development and utilization energy is more more and more paid attention to.Solar energy power generating is the important component part of new forms of energy, is considered to new energy technology the most promising on the our times.Photovoltaic combining inverter considers to require photovoltaic grid-connected inverting system and electrical network to realize electrical isolation from the angle of safety.And electrical isolation realizes with Industrial Frequency Transformer or high frequency transformer usually.The power frequency parallel network reverse at first converts alternating current into through the direct current that AC/DC (DC/AC) converter is exported photovoltaic array, and then links to each other with electrical network through Industrial Frequency Transformer.The high frequency photovoltaic combining inverter at first carries out the electric pressure conversion through band high-frequency isolation transformer DC-to-DC (DC/DC) converter with direct voltage, passes through the DC/AC inverter then with energy feed-in electrical network.Because the worker is separated or the adding of high-frequency isolation transformer, make the whole efficiency of system descend 1%-2%.Transformerless type combining inverter structure does not contain transformer (low frequency and high frequency), has the low absolute predominance of efficient height, volume, weight and cost.Therefore, increasing commercial photovoltaic combining inverter adopts this topological structure.But no isolating transformer combining inverter makes to have had between photovoltaic (PV) and the electrical network and is electrically connected, and common mode current increases greatly, brings potential safety hazard.A problem that adopts transformerless combining inverter to solve is how to eliminate common-mode voltage to form the leakage current that the loop produced in parasitic capacitance (between PV and the earth).Germany SMA SunnyBoy company adopts H5 topological structure (Chinese utility model patent number: 200510079923.1); In this topological structure; V1 and V2 are in the positive-negative half-cycle conducting separately of power network current; V4, V5 modulate with switching frequency at the positive half cycle of electrical network, and V2, V5 modulate with switching frequency at the electrical network negative half-cycle.This transless topological structure can well solve leakage problem; Simultaneously, its peak efficiency reaches 98.1%, and European efficient reaches 97.7%.Sunways company adopts HERIC (european patent number: EP 1369985 A2) topological structure; This topology is the improvement to the full-bridge topology of bipolarity modulation; Promptly the AC side in the full-bridge topology increases a two-way afterflow branch road of being made up of 2 IGBT; Make continuous current circuit and DC side break off, can effectively solve leakage problem equally, its peak efficiency reaches 96.3%.Document (Transformerless Inverters for Single-phase Photovoltaic Systems [J]. IEEE Transactions on power electronics; 2007; 22 (2): 693-697) propose a kind of new topological structure FB-DCBP (full-bridge with dc-bypass); At the line voltage positive half period, switching tube S1, S4 remain conducting, switching tube S5, S6 and S2, S3 alternate conduction; At the line voltage negative half-cycle, switching tube S2, S3 remain conducting, switching tube S5, S6 and S1, S4 alternate conduction.This topological structure has well solved leakage problem, and its peak efficiency can reach 97.4%.Summary of the invention
The purpose of the utility model provides efficient single-phase photovoltaic grid-connected inverter; If it does not add control to transformerless single-phase photovoltaic grid-connected inverter; Avoid producing between photovoltaic battery panel and the earth phenomenon of very big leakage current, make that leakage current is very little, reach and be incorporated into the power networks and the safety requirement.
In order to solve the existing problem of background technology; The utility model is to adopt following technical scheme: it comprises photovoltaic battery panel PV, low frequency switching tube S1 and S3, HF switch pipe S2 and S4, sustained diode 1-D2, capacitor C 1-C2, inductance L 1-L2 and relay K 1-K2; One end of electrical network is connected with an end of relay K 1; The other end of relay K 1 is connected with the positive pole of capacitor C 2, the emitter of low frequency switching tube S1 and an end of inductance L 2 respectively; The negative pole of capacitor C 2 is connected with an end of relay K 2, the emitter of low frequency switching tube S3 and an end of inductance L 1 respectively; The collector electrode of low frequency switching tube S1 is connected with the negative pole of sustained diode 2, the collector electrode of low frequency switching tube S3, the negative pole of sustained diode 1, the positive pole of capacitor C 1 and the end of photovoltaic battery panel PV respectively; The other end of inductance L 2 is connected with the positive pole of sustained diode 2 and the grid of HF switch pipe S2 respectively; The negative pole of the other end of photovoltaic battery panel PV and capacitor C 1 is connected with the emitter of HF switch pipe S2 and the emitter of HF switch pipe S4 respectively; The other end of inductance L 1 is connected with the positive pole of sustained diode 1 and the grid of HF switch pipe S4 respectively, and the other end of relay K 2 is connected with the other end of electrical network.
If the utility model does not add control to transformerless single-phase photovoltaic grid-connected inverter, avoid producing between photovoltaic battery panel and the earth phenomenon of very big leakage current, make that leakage current is very little, reach and be incorporated into the power networks and the safety requirement; Control simply relatively, whole efficiency improves, and its topological structure peak efficiency can reach 98%.
Description of drawings:
Fig. 1 is the structural representation of the utility model.
Fig. 2 is the loop of its leakage current among Fig. 1.
Fig. 3 is the structural representation of the utility model PWM modulating mode.
The structural representation of current direction when Fig. 4 opens for line voltage positive half period HF switch pipe S4 among Fig. 1.
Fig. 5 is the structural representation of current direction when line voltage positive half period HF switch pipe S4 turn-offs among Fig. 1.
The structural representation of current direction when Fig. 6 opens for line voltage negative half-cycle HF switch pipe S2 among Fig. 1.
Fig. 7 is the structural representation of current direction when line voltage negative half-cycle HF switch pipe S2 turn-offs among Fig. 1.
Fig. 8 is the structural representation of the utility model control strategy.
Fig. 9-Figure 10 is the voltage U ab that exports under the utility model different modulating pattern and the structural representation of leakage current iCM.
Embodiment:
With reference to Fig. 1-Figure 10; This embodiment adopts following technical scheme: it comprises photovoltaic battery panel PV, low frequency switching tube S1 and S3, HF switch pipe S2 and S4, sustained diode 1-D2, capacitor C 1-C2, inductance L 1-L2 and relay K 1-K2; One end of electrical network is connected with an end of relay K 1; The other end of relay K 1 is connected with the positive pole of capacitor C 2, the emitter of low frequency switching tube S1 and an end of inductance L 2 respectively; The negative pole of capacitor C 2 is connected with an end of relay K 2, the emitter of low frequency switching tube S3 and an end of inductance L 1 respectively; The collector electrode of low frequency switching tube S1 is connected with the negative pole of sustained diode 2, the collector electrode of low frequency switching tube S3, the negative pole of sustained diode 1, the positive pole of capacitor C 1 and the end of photovoltaic battery panel PV respectively; The other end of inductance L 2 is connected with the positive pole of sustained diode 2 and the grid of HF switch pipe S2 respectively; The negative pole of the other end of photovoltaic battery panel PV and capacitor C 1 is connected with the emitter of HF switch pipe S2 and the emitter of HF switch pipe S4 respectively; The other end of inductance L 1 is connected with the positive pole of sustained diode 1 and the grid of HF switch pipe S4 respectively, and the other end of relay K 2 is connected with the other end of electrical network.
Described photovoltaic battery panel PV is that whole system comprises that control circuit provides electric energy.Under the condition of illumination, solar battery array is that (DC-AC) inverter converts direct current into interchange to electric energy, to the electrical network transmission power through direct current change interchange with the transform light energy that is received by day; At dark, whole system quits work automatically, utilizes relay that output and electrical network are broken off.
In transformerless non-isolated grid-connected system; Exist between electrical network and the photovoltaic array and directly be electrically connected; Owing to have parasitic capacitance between photovoltaic array and the ground, form and form the common mode resonance loop by parasitic capacitance, DC side and alternating current filter and electric network impedance.The variation meeting of common-mode voltage produces common mode current (leakage current) on the parasitic capacitance on parasitic capacitance.For resisting the leakage current of the single-phase photovoltaic DC-to-AC converter of transless, should make common-mode voltage variation smaller as far as possible.If can Ucm be certain value, then can eliminate common mode current basically, i.e. power device employing PWM control makes the voltage sum that a and b point are ordered to O satisfy:
As the key link of combining inverter, transformation of electrical energy is play a part very crucial.Make photovoltaic DC-to-AC converter output current and line voltage same-phase through control H bridge and continuous current circuit, realize the output of photovoltaic array maximum power simultaneously and suppress leakage current, improve the conversion efficiency of whole photovoltaic system.
Obtain the information of electrical network space angle through phase-locked loop, when the positive half cycle of line voltage, during the positive half cycle of line voltage, low frequency switching tube S1 keeps open-minded always, and HF switch pipe S4 adopts the PWM modulation, and low frequency switching tube S3 and HF switch pipe S2 close.
When HF switch pipe S4 opened, this moment, the current circuit of DC-AC inverter was:
Switching tube S1-electrical network-inductance L 1-HF switch pipe S4---capacitor C 1
When HF switch pipe S4 turn-offed, this moment, the current circuit of DC-AC inverter was:
Switching tube S1-electrical network-inductance L 1-sustained diode 1-switching tube S1
Obtain the information of electrical network space angle through phase-locked loop, when the line voltage negative half period, low frequency switching tube S3 keeps open-minded always, and HF switch pipe S2 adopts the PWM modulation.Low frequency switching tube S1 and HF switch pipe S4 close.
When HF switch pipe S2 opened, this moment, the current circuit of DC-AC inverter was:
Switching tube S3-electrical network-inductance L 2-HF switch pipe S2---capacitor C 1
When HF switch pipe S2 turn-offed, this moment, the current circuit of DC-AC inverter was:
Switching tube S3-electrical network-inductance L 2-sustained diode 2-switching tube S3
If this embodiment does not add control to transformerless single-phase photovoltaic grid-connected inverter, avoid producing between photovoltaic battery panel and the earth phenomenon of very big leakage current, make that leakage current is very little, reach and be incorporated into the power networks and the safety requirement; Control simply relatively, whole efficiency improves, and its topological structure peak efficiency can reach 98%.
Claims (1)
1. efficient single-phase photovoltaic grid-connected inverter; It is characterized in that it comprise photovoltaic battery panel (PV), low frequency switching tube (S1) and (S3), HF switch pipe (S2) and (S4), fly-wheel diode (D1)-(D2), electric capacity (C1)-(C2), inductance (L1)-(L2) and relay (K1)-(K2); One end of electrical network is connected with an end of relay (K1); The other end of relay (K1) is connected with the positive pole of electric capacity (C2), the emitter of low frequency switching tube (S1) and an end of inductance (L2) respectively; The negative pole of electric capacity (C2) is connected with an end of relay (K2), the emitter of low frequency switching tube (S3) and an end of inductance (L1) respectively; The collector electrode of low frequency switching tube (S1) is connected with the negative pole of fly-wheel diode (D2), the collector electrode of low frequency switching tube (S3), the negative pole of fly-wheel diode (D1), the positive pole of electric capacity (C1) and an end of photovoltaic battery panel (PV) respectively; The other end of inductance (L2) is connected with the positive pole of fly-wheel diode (D2) and the grid of HF switch pipe (S2) respectively; The negative pole of the other end of photovoltaic battery panel (PV) and electric capacity (C1) is connected with the emitter of HF switch pipe (S2) and the emitter of HF switch pipe (S4) respectively; The other end of inductance (L1) is connected with the positive pole of fly-wheel diode (D1) and the grid of HF switch pipe (S4) respectively, and the other end of relay (K2) is connected with the other end of electrical network.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201120387329XU CN202261071U (en) | 2011-10-13 | 2011-10-13 | High-efficiency single-phase photovoltaic grid-connected inverter |
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| CN201120387329XU CN202261071U (en) | 2011-10-13 | 2011-10-13 | High-efficiency single-phase photovoltaic grid-connected inverter |
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| CN202261071U true CN202261071U (en) | 2012-05-30 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103178741A (en) * | 2013-03-04 | 2013-06-26 | 东南大学 | Interleaved parallel switch full-bridge inverter and interleaved parallel control method |
| CN103580524A (en) * | 2012-08-07 | 2014-02-12 | 郭晓瑞 | Novel H4 bridge multi-level grid-connected-connected inverter circuit |
| CN103683313A (en) * | 2012-09-13 | 2014-03-26 | 武汉金天新能源科技有限公司 | Photovoltaic inverter employing hybrid type power device |
| CN103795085A (en) * | 2014-03-03 | 2014-05-14 | 苏州大学 | Photovoltaic grid-connected inverter |
| CN108988675A (en) * | 2018-09-30 | 2018-12-11 | 华南理工大学 | A kind of single-phase non-isolated MOSFET gird-connected inverter |
-
2011
- 2011-10-13 CN CN201120387329XU patent/CN202261071U/en not_active Expired - Lifetime
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103580524A (en) * | 2012-08-07 | 2014-02-12 | 郭晓瑞 | Novel H4 bridge multi-level grid-connected-connected inverter circuit |
| CN103683313A (en) * | 2012-09-13 | 2014-03-26 | 武汉金天新能源科技有限公司 | Photovoltaic inverter employing hybrid type power device |
| CN103683313B (en) * | 2012-09-13 | 2016-11-23 | 华中科技大学 | A kind of photovoltaic DC-to-AC converter using mixed type power device |
| CN103178741A (en) * | 2013-03-04 | 2013-06-26 | 东南大学 | Interleaved parallel switch full-bridge inverter and interleaved parallel control method |
| CN103795085A (en) * | 2014-03-03 | 2014-05-14 | 苏州大学 | Photovoltaic grid-connected inverter |
| CN108988675A (en) * | 2018-09-30 | 2018-12-11 | 华南理工大学 | A kind of single-phase non-isolated MOSFET gird-connected inverter |
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| Date | Code | Title | Description |
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| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CX01 | Expiry of patent term | ||
| CX01 | Expiry of patent term |
Granted publication date: 20120530 |