CN204928610U - Single -phase non - isolated form photovoltaic grid -connected inverter - Google Patents
Single -phase non - isolated form photovoltaic grid -connected inverter Download PDFInfo
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- CN204928610U CN204928610U CN201520616102.6U CN201520616102U CN204928610U CN 204928610 U CN204928610 U CN 204928610U CN 201520616102 U CN201520616102 U CN 201520616102U CN 204928610 U CN204928610 U CN 204928610U
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- 230000002459 sustained effect Effects 0.000 description 3
- 230000000295 complement effect Effects 0.000 description 2
- 230000001939 inductive effect Effects 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000007812 deficiency Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
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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 single -phase non - isolated form photovoltaic grid -connected inverter, including H bridge circuit and two freewheeling diode, the direct current of H bridge circuit end is used for connecting the dc bus, exchanges the end and is used for connecting the electric wire netting, is connected with an electric capacity branch road between the dc bus, this H bridge circuit includes first switch tube, the second switch pipe, the third switch tube, the fourth switch tube, the 5th switch tube and the 6th switch tube, electric capacity two the same electric capacity of route concatenate the component, interconnecting link between the tie point between first switch tube and the second switch pipe and the tie point of two electric capacity goes up the reverse clamping diode that has concatenated, the 2nd clamping diode has concatenated on the interconnecting link between the tie point between third switch tube and the fourth switch tube and the tie point of two electric capacity. Through introducing catching diode and voltage -dividing capacitor, with bridge mouth voltage clamp to half battery voltage between the electric current afterflow period to can eliminate common mode voltage completely theoretically, have littleer leakage current.
Description
Technical field
The utility model relates to a kind of single-phase non-isolated photovoltaic grid-connected inverter, belongs to parallel network reverse topologies field.
Background technology
Photovoltaic parallel in system refers to that the direct current produced by photovoltaic array is converted to line voltage the alternating current of same amplitude, same to frequency, homophase through combining inverter, and the system that realization is connected with electrical network.The normal isolation photovoltaic combining inverter adopting band power frequency or high frequency transformer in photovoltaic parallel in system, which ensure that between electrical network and photovoltaic system electrically rationally, thus personnel protection is provided and avoids the common mode current between photovoltaic system and ground.But according to Industrial Frequency Transformer, its volume is large, Heavy Weight and expensive; According to high frequency transformer, power conversion circuit will be divided into several grades, make control from being complicated, also reduce the efficiency of system simultaneously.
In order to overcome the above-mentioned deficiency having the isolation type grid-connected system of transformer, transformerless non-isolation type inverter is studied.Non-isolated photovoltaic grid-connected inverter requires that efficiency is high, cost is low, can bear great fluctuation process voltage that photovoltaic cell exports and exchange output to meet the quality of power supply of Standard.But because inverter does not have transformer isolation, make the switching device high frequency mo of inverter produce leakage current by system parasitic electric capacity, this can cause EMC interference to increase the weight of, and leakage current exceeds standard and even can damage equipment and the person.
Unipolarity modulator approach uses more modulator approach in current single-phase photovoltaic inverter, the advantages such as direct voltage utilance is high, filter inductance current pulsation is little that it has.But larger common-mode voltage can be produced when switch motion, in order to effectively suppress common-mode voltage, Chinese patent CN102157955A discloses a kind of photovoltaic combining inverter, in this inverter circuit, altogether be connected in series six switching tubes in H bridge, the afterflow being electric current by switching tube wherein and fly-wheel diode provides a path, and solar cell end and electrical network are departed from, thus effectively inhibit common-mode voltage, but combining inverter disclosed in this application can not eliminate common-mode voltage completely.
Utility model content
The purpose of this utility model is to provide a kind of single-phase non-isolated photovoltaic grid-connected inverter, can not eliminate the problem of common-mode voltage in order to solve existing photovoltaic combining inverter completely.
For achieving the above object, scheme of the present utility model comprises a kind of single-phase non-isolated photovoltaic grid-connected inverter, comprise H-bridge circuit and two fly-wheel diodes, the DC terminal of H-bridge circuit is for connecting DC bus, exchanging end for connecting electrical network, between described DC bus, being connected with a capacitive branch, this H-bridge circuit comprises four brachium pontis, first brachium pontis and the second brachium pontis form upper and lower bridge arm, 3rd brachium pontis and four bridge legs form upper and lower bridge arm, first brachium pontis is serially connected with the first switching tube and second switch pipe, second brachium pontis is serially connected with the 3rd switching tube and the 4th switching tube, 3rd brachium pontis is serially connected with the 5th switching tube, four bridge legs is serially connected with the 6th switching tube, tie point between described first switching tube and second switch pipe is oppositely connected in series the first fly-wheel diode with on the connection line between the 5th switching tube and the tie point of the 6th switching tube, tie point between described 3rd switching tube and the 4th switching tube is connected in series the second fly-wheel diode with on the connection line between the 5th switching tube and the tie point of the 6th switching tube, described capacitive branch is made up of two identical capacitance series, connection line between the tie point of the tie point between described first switching tube and second switch pipe and described two electric capacity is oppositely serially connected with the first clamping diode, tie point between described 3rd switching tube and the 4th switching tube and the connection line between the tie point of described two electric capacity are serially connected with the second clamping diode.
Described switching tube is IGBT and/or MOSFET, and when switching tube is IGBT, the anode of switching tube is the collector electrode of IGBT, and the negative electrode of switching tube is the emitter of IGBT; When switching tube is MOSFET, the anode of switching tube is the drain electrode of MOSFET, and the negative electrode of switching tube is the source electrode of MOSFET.
Each described switching tube equal reverse parallel connection diode.
The combining inverter that the utility model provides is on the basis of disclosed combining inverter in the introduction, tie point between two switching tubes and be serially connected with clamping diode between the tie point between two derided capacitors, by introducing clamp diode and derided capacitors, by bridge mouth voltage clamping to two/mono-cell voltage between the electric current afterflow period, thus common-mode voltage can be eliminated completely theoretically, there is less leakage current.And, relative to prior art, just introducing clamp diode and derided capacitors can realize the object almost eliminating common-mode voltage completely to this combining inverter structure, so this combining inverter structure is simple, and the effect reducing common-mode voltage is very remarkable.
Accompanying drawing explanation
Fig. 1 is the structural representation of combining inverter disclosed in background technology;
Fig. 2 is the structural representation of the combining inverter that the utility model provides;
Fig. 3 is switching tube drive singal schematic diagram;
When Fig. 4-1 is line voltage positive half cycle, the operation mode figure of combining inverter;
When Fig. 4-2 is line voltage negative half periods, the operation mode figure of combining inverter.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in more detail.
Single-phase non-isolated photovoltaic grid-connected inverter as shown in Figure 2, comprises capacitive branch and H-bridge circuit, and the DC terminal of H-bridge circuit connects DC bus, exchanges end and connects electrical network.DC bus connects solar cell, connects above-mentioned capacitive branch between DC bus, this capacitive branch is serially connected with two identical electric capacity, electric capacity Cdc1 and electric capacity Cdc2.H-bridge circuit has four brachium pontis, and the first brachium pontis and the second brachium pontis form upper and lower bridge arm, and the 3rd brachium pontis and four bridge legs form upper and lower bridge arm, four brachium pontis are connected in series altogether six switching tubes, particularly, the first brachium pontis is serially connected with two switching tubes, is respectively: switching tube S1, switching tube S5; Second brachium pontis is serially connected with two switching tubes, is respectively: switching tube S6 and switching tube S2, the 3rd brachium pontis is serially connected with a switching tube, for: switching tube S3; Four bridge legs is serially connected with a switching tube, for: switching tube S4.Tie point between switching tube S5 and switching tube S6 is that of this H-bridge circuit exchanges end, and the tie point between switching tube S3 and switching tube S4 is another interchange end of this H-bridge circuit.
In this H-bridge circuit, the anode of the negative electrode connecting valve pipe S5 of switching tube S1, the anode of the negative electrode connecting valve pipe S6 of switching tube S5, the anode of the negative electrode connecting valve pipe S2 of switching tube S6; The anode of the negative electrode connecting valve pipe S4 of switching tube S3.The anode of the anode connecting valve pipe S3 of switching tube S1, the negative electrode of the negative electrode connecting valve pipe S4 of switching tube S2, the anode of switching tube S1 is connected positive and negative DC bus respectively with the negative electrode of switching tube S2.
Tie point between switching tube S1 and switching tube S5 and the connection line between the tie point between switching tube S3 and switching tube S4 are oppositely serially connected with sustained diode 3, the tie point between switching tube S6 and switching tube S2 and the connection line between the tie point between switching tube S3 and switching tube S4 are serially connected with sustained diode 4.Connection line between the mid point (tie point) of the tie point between switching tube S1 and switching tube S5 and electric capacity Cdc1 and electric capacity Cdc2 is oppositely serially connected with clamping diode D1, the connection line between the mid point (tie point) of the tie point between switching tube S6 and switching tube S2 and electric capacity Cdc1 and electric capacity Cdc2 is serially connected with clamping diode D2.
In the utility model, the direction of the connection line between A and B is: A to B; The direction of the connection line between B and A is: B to A.
One end exchanging end and connect network access filter L1 of H-bridge circuit, the other end of network access filter L1 connects electrical network; One end exchanging end and connect network access filter L2 of H-bridge circuit, the other end of network access filter L2 connects electrical network.
In this H-bridge circuit, switching tube S5, switching tube S6 and sustained diode 3, D4 form continuous current circuit, and clamping diode D1, D2 and electric capacity Cdc1, Cdc2 form clamper loop.
Suppose that grid-connected voltage and current phase place is identical, as shown in Figure 3, line voltage just half power frequency period time, switching tube S1 and switching tube S4 is with switching frequency conducting simultaneously, switching tube S5 often opens, and switching tube S6 and switching tube S1, switching tube S4 complementary duty, switching tube S2, S3 are in off state.During voltage negative half power frequency period, switching tube S2 and switching tube S3 is with switching frequency conducting simultaneously, and switching tube S6 often opens, and switching tube S5 and switching tube S2, S3 complementary duty, switching tube S1, S4 are in off state.
The positive half cycle of line voltage:
During switching tube S1, S4, S5 conducting, switching tube S6, S2, S3 turn off, and electric current gets back to negative busbar, as shown in Fig. 4-1 through switching tube S1, switching tube S5, filter inductance L1, electrical network and filter capacitor C, filter inductance L2, switching tube S4 successively from positive bus-bar.
When switching tube S1, S4 turn off, switching tube S5, S6 conducting, inductive current is by filter inductance L1, electrical network and filter capacitor C, filter inductance L2, diode D3, switching tube S5 afterflow.A point is equal with B point voltage, and, when A point voltage is higher than O point, through switching tube S6 and diode D2, A point voltage is clamped to O point, when A point voltage is lower than O point, through diode D1 and switching tube S5 by A point voltage clamper in O point.By above-mentioned control, between the electric current afterflow period, A point, B point, O point three point voltage are equal all the time, are 1/2nd of cell voltage, as shown in Fig. 4-1.
Line voltage negative half period:
During switching tube S2, S3, S6 conducting, switching tube S1, S4, S5 turn off, and electric current gets back to negative busbar through switching tube S3, filter inductance L2, electrical network and filter capacitor C, filter inductance L1, switching tube S6, switching tube S2 successively from positive bus-bar, as shown in the Fig. 4-2.
When switching tube S2, S3 turn off, switching tube S5, S6 conducting, inductive current is by filter inductance L2, electrical network and filter capacitor C, filter inductance L1, switching tube S6, diode D4 afterflow.A point is equal with B point voltage, and, when A point voltage is higher than O point, through switching tube S6 and diode D2, A point voltage is clamped to O point, when A point voltage is lower than O point, through diode D1 and switching tube S5 by A point voltage clamper in O point.By above-mentioned control, between the electric current afterflow period, A point, B point, O point three point voltage are equal all the time, are 1/2nd of cell voltage, as shown in the Fig. 4-2.
In above-described embodiment, first brachium pontis is serially connected with four switching tubes, second brachium pontis is serially connected with two switching tubes, as other embodiment, first brachium pontis is serially connected with two switching tubes, second brachium pontis is serially connected with four switching tubes, and its concrete connected mode is identical with the principle of the connected mode in above-described embodiment, does not repeat here.
In this embodiment, switching tube can be IGBT, MOSFET, can also be half control type device or the wholly-controled device of other types.When switching tube is IGBT, the anode of switching tube is the collector electrode of IGBT, and the negative electrode of switching tube is the emitter of IGBT; When switching tube is MOSFET, the anode of switching tube is the drain electrode of MOSFET, and the negative electrode of switching tube is the source electrode of MOSFET.
In addition, in this embodiment, switching tube can be all the switching tube of a type, such as switching tube is all IGBT and MOSFET; Certainly, the switching tube in inverter can also be used in combination, such as the switching tube in inverter has IGBT, also has MOSFET.
In addition, the content be not described in detail in specification to belong in background technology the technical scheme in disclosed patent CN102157955A and well known to a person skilled in the art prior art.
Be presented above concrete execution mode, but the utility model is not limited to described execution mode.Basic ideas of the present utility model are above-mentioned basic scheme, and for those of ordinary skill in the art, according to instruction of the present utility model, designing the model of various distortion, formula, parameter does not need to spend creative work.The change carried out execution mode when not departing from principle of the present utility model and spirit, amendment, replacement and modification still fall in protection range of the present utility model.
Claims (3)
1. a single-phase non-isolated photovoltaic grid-connected inverter, comprises H-bridge circuit and two fly-wheel diodes, and the DC terminal of H-bridge circuit, for connecting DC bus, exchanging end for connecting electrical network, being connected with a capacitive branch between described DC bus, this H-bridge circuit comprises four brachium pontis, first brachium pontis and the second brachium pontis form upper and lower bridge arm, 3rd brachium pontis and four bridge legs form upper and lower bridge arm, first brachium pontis is serially connected with the first switching tube and second switch pipe, second brachium pontis is serially connected with the 3rd switching tube and the 4th switching tube, 3rd brachium pontis is serially connected with the 5th switching tube, four bridge legs is serially connected with the 6th switching tube, tie point between described first switching tube and second switch pipe is oppositely connected in series the first fly-wheel diode with on the connection line between the 5th switching tube and the tie point of the 6th switching tube, tie point between described 3rd switching tube and the 4th switching tube is connected in series the second fly-wheel diode with on the connection line between the 5th switching tube and the tie point of the 6th switching tube, it is characterized in that, described capacitive branch is made up of two identical capacitance series, connection line between the tie point of the tie point between described first switching tube and second switch pipe and described two electric capacity is oppositely serially connected with the first clamping diode, tie point between described 3rd switching tube and the 4th switching tube and the connection line between the tie point of described two electric capacity are serially connected with the second clamping diode.
2. single-phase non-isolated photovoltaic grid-connected inverter according to claim 1, is characterized in that, described switching tube is IGBT and/or MOSFET, and when switching tube is IGBT, the anode of switching tube is the collector electrode of IGBT, and the negative electrode of switching tube is the emitter of IGBT; When switching tube is MOSFET, the anode of switching tube is the drain electrode of MOSFET, and the negative electrode of switching tube is the source electrode of MOSFET.
3. single-phase non-isolated photovoltaic grid-connected inverter according to claim 1 and 2, is characterized in that, each described switching tube equal reverse parallel connection diode.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520616102.6U CN204928610U (en) | 2015-08-14 | 2015-08-14 | Single -phase non - isolated form photovoltaic grid -connected inverter |
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| CN201520616102.6U CN204928610U (en) | 2015-08-14 | 2015-08-14 | Single -phase non - isolated form photovoltaic grid -connected inverter |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111934572A (en) * | 2020-06-29 | 2020-11-13 | 中国电力科学研究院有限公司 | Super-large-scale energy storage MMC converter device and energy storage control method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN111934572A (en) * | 2020-06-29 | 2020-11-13 | 中国电力科学研究院有限公司 | Super-large-scale energy storage MMC converter device and energy storage control method |
| CN111934572B (en) * | 2020-06-29 | 2022-10-04 | 中国电力科学研究院有限公司 | Super-large-scale energy storage MMC converter device and energy storage control method |
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Effective date of registration: 20160425 Address after: 102200, 270 East Village Road, Beijing, Changping District Patentee after: State Grid Smart Grid Institute Patentee after: State Grid Corporation of China Patentee after: State Grid Zhejiang Electric Power Company Patentee after: Xuji Electric Co., Ltd. Patentee after: Xi'an XJ Power Electronics Technology Co., Ltd. Address before: 100031 Xicheng District West Chang'an Avenue, No. 86, Beijing Patentee before: State Grid Corporation of China Patentee before: State Grid Smart Grid Institute Patentee before: Xuji Electric Co., Ltd. Patentee before: Xi'an XJ Power Electronics Technology Co., Ltd. |