CN203911800U - High-frequency isolated photovoltaic inverter - Google Patents
High-frequency isolated photovoltaic inverter Download PDFInfo
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- CN203911800U CN203911800U CN201420346740.6U CN201420346740U CN203911800U CN 203911800 U CN203911800 U CN 203911800U CN 201420346740 U CN201420346740 U CN 201420346740U CN 203911800 U CN203911800 U CN 203911800U
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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
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Abstract
The utility model discloses a high-frequency isolated photovoltaic inverter. The photovoltaic inverter comprises a front-end high-frequency isolated CUK circuit and a rear-end full bridge inverter. The front-end high-frequency isolated CUK circuit comprises an inductor L1, a switch tube Q1, a capacitor C1, a transformer T1, a capacitor C2, a diode D1, a inductor L2 and a capacitor C3. The switch tube Q1 employs an insulated gated bipolar translator (IGBT). The rear-end full bridge inverter is composed of four switch tubes. Upper bridge arm switch tubes Q2 and Q4 employ the IGBT, and lower bridge arm switch tubes Q3 and Q5 employ a MOSFET. The high-frequency isolated photovoltaic inverter disclosed by the utility model has the advantages of simple drive circuits, high transmission efficiency and small size and the like. Electrical isolation of a solar cell panel and electrical network is realized and the high-frequency isolated photovoltaic inverter can be widely applied in a solar energy grid-connected photovoltaic power generation system.
Description
Technical field
The utility model belongs to technical field of power generation, relates to a kind of solar photovoltaic grid-connection generating equipment, especially a kind of high-frequency isolation type photovoltaic DC-to-AC converter.
Background technology
Grid-connected photovoltaic system is mainly made up of solar panel, photovoltaic DC-to-AC converter and electrical network.Photovoltaic DC-to-AC converter is the nucleus equipment that connects solar panel and electrical network.Be used for controlling the function that solar panel runs on maximum power point and injects sinusoidal current to electrical network.
The topological structure that current photovoltaic DC-to-AC converter adopts is divided into transless isolated form and transformer isolation type.
Transless isolated form photovoltaic DC-to-AC converter has that cost is low, volume is little, lightweight advantage, is widely used in the occasion of small-power electricity generation system.But owing to there is no transformer isolation, between solar panel array and electrical network, there is electrical connection, when serious, can endanger personal safety.The technical problem such as DC component control and leakage current Real-Time Monitoring in grid-connected current is the difficult problem that such inverter need to be faced simultaneously.
Transformer isolation type photovoltaic DC-to-AC converter can be realized the electrical isolation of solar panel and electrical network, and easy and hull cell is used in conjunction with.The type inverter can be divided into again power frequency isolated form and high-frequency isolation type.
Power frequency isolated inverter first converts by DC/AC, and solar cell direct current energy is converted into AC energy, is then connected with electrical network by Industrial Frequency Transformer, completes and boosts and and the isolation of electrical network.Audio noise is large, volume is large and heavy, and conversion efficiency is low, and this is the major defect of power frequency isolated inverter.
High-frequency isolation inverter is first boosted the direct current of solar cell to be converted into high direct voltage by isolation DC/DC converter, then exports by inverter circuit inversion, after low pass filter, is directly connected with electrical network.Due to the buffer action of high frequency transformer, can directly the output of inverter directly be connected to electrical network by inductance, greatly reduce its equipment volume and noise, and improved the flexibility of controlling.Have advantages of lightweight, volume is little, cost is low and the isolation of solar panel and electrical network.
High-frequency isolation topological structure has positive activation type, inverse-excitation type, push-pull type, semibridge system, full-bridge type.In positive activation type, inverse-excitation type, push-pull type structure, there is the single-phase magnetic bias of transformer, the problem that utilance is low; For semibridge system, full-bridge type, there is drive circuit complexity, the problem that upper and lower switching tube is straight-through.
Utility model content
The technical problems to be solved in the utility model is: a kind of high-frequency isolation type photovoltaic DC-to-AC converter is provided, and the topological structure of this inverter can be realized the electrical isolation of solar panel array and electrical network, and controls simple and easyly, and energy transmission efficiency is high.
The utility model is to be achieved through the following technical solutions:
A kind of high-frequency isolation type photovoltaic DC-to-AC converter, comprise preceding stage high frequency isolation cuk converter and rear class full bridge inverter, this preceding stage high frequency isolation cuk converter comprises inductance L 1, switching tube Q1, capacitor C 1, transformer T1, capacitor C 2, diode D1, inductance L 2 and capacitor C 3, inductance L 1 one end is connected with input voltage Vpv, the other end is connected with capacitor C 1 one end, capacitor C 1 other end is connected with transformer T1 input, between switching tube Q1 one end access inductance L 1 and capacitor C 1, the other end is connected with transformer T1 input with input voltage Vpv respectively, capacitor C 2 one end are connected with transformer T1 output, one end is connected with output voltage V dc after inductance L 2, output voltage V dc is also connected with transformer T1 output, between diode D1 one end access capacitor C 2 and inductance L 2, the other end is connected with transformer T1 output, capacitor C 3 one end are connected with output voltage V dc, the other end is connected with transformer T1 output, rear class full bridge inverter comprises brachium pontis switching tube Q2, Q3 and lower brachium pontis switching tube Q4, tetra-switching tubes of Q5 and is connected respectively diode D2, D3, D4, the D5 on switching tube Q2, Q3, Q4, Q5, between output voltage V dc, have access to switching tube Q2, the Q3 of series connection and switching tube Q4, the Q5 of series connection, after inductance L 3 is connected with capacitor C 4, inductance L 3 accesses between switching tube Q2, Q3, capacitor C 4 accesses between switching tube Q4, Q5, in capacitor C 4, is connected with alternating voltage.
Switching tube Q1 adopts IGBT pipe, and upper brachium pontis switching tube Q2, Q4 adopt IGBT pipe, and lower brachium pontis switching tube Q3, Q5 adopt MOSFET pipe.
The pass of the output voltage V dc of high-frequency isolation cuk converter and input voltage Vpv is Vdc=Vpv × D/n (1-D), the wherein turn ratio n=n1/n2 of transformer (former limit/secondary), pulse duty factor D=ton/T, ton is ON time, T is turn-on cycle.
The driving signal of the switching tube Q1 of high-frequency isolation cuk converter is the square-wave signal of frequency 15KHz, and the size of the duty ratio D of square-wave signal and input voltage Vpv is inversely proportional to.
Upper brachium pontis IGBT switching tube Q2, the Q4 of full bridge inverter, as polarity controller, are operated in power frequency 50Hz, and switch mosfet pipe Q3, the Q5 of lower brachium pontis carry out high frequency switching, control the amplitude of inversion output.
Compared with prior art, the utlity model has following useful technique effect:
The advantages such as the high-frequency isolation type photovoltaic DC-to-AC converter that the utility model provides, has drive circuit simple, and efficiency of transmission is high, and volume is little, can realize the electrical isolation of solar panel and electrical network, have volume little, lightweight feature.Can be widely used in solar energy grid-connected photovoltaic system.And because no matter switching tube is in conducting or between the off period, energy can be delivered to output by inductance and electric capacity, and therefore Energy Transfer is high.
The utility model full bridge inverter adopts IBGT, MOSFET hybrid circuit.Because the conduction voltage drop of MOSFET pipe is linear, the in the situation that of underloading, have lower conduction voltage drop, and the conduction voltage drop of IGBT pipe is nonlinear characteristic, has little conduction voltage drop under full load conditions.Adopt IGBT pipe, MOSFET pipe to mix composition inversion full-bridge circuit, there is very high inversion efficiency, no matter under underloading or full load conditions.
Brief description of the drawings
Fig. 1 is a kind of high-frequency isolation type photovoltaic DC-to-AC converter circuit theory diagrams.
Fig. 2 is the equivalent circuit diagram of high-frequency isolation type cuk converter in the time of switch conduction.
Fig. 3 is the equivalent circuit diagram of high-frequency isolation type cuk converter in the time that switch ends.
Fig. 4 is the driving signal of inverter circuit and output voltage, inverter current analogous diagram.
Embodiment
Below in conjunction with accompanying drawing, the utility model is described in further detail:
Referring to Fig. 1, a kind of high-frequency isolation type photovoltaic DC-to-AC converter, comprise preceding stage high frequency isolation cuk converter and rear class full bridge inverter, this preceding stage high frequency isolation cuk converter comprises inductance L 1, switching tube Q1, capacitor C 1, transformer T1, capacitor C 2, diode D1, inductance L 2 and capacitor C 3, inductance L 1 one end is connected with input voltage Vpv, the other end is connected with capacitor C 1 one end, capacitor C 1 other end is connected with transformer T1 input, between switching tube Q1 one end access inductance L 1 and capacitor C 1, the other end is connected with transformer T1 input with input voltage Vpv respectively, capacitor C 2 one end are connected with transformer T1 output, one end is connected with output voltage V dc after inductance L 2, output voltage V dc is also connected with transformer T1 output, between diode D1 one end access capacitor C 2 and inductance L 2, the other end is connected with transformer T1 output, capacitor C 3 one end are connected with output voltage V dc, the other end is connected with transformer T1 output, rear class full bridge inverter comprises brachium pontis switching tube Q2, Q3 and lower brachium pontis switching tube Q4, tetra-switching tubes of Q5 and is connected respectively diode D2, D3, D4, the D5 on switching tube Q2, Q3, Q4, Q5, between output voltage V dc, have access to switching tube Q2, the Q3 of series connection and switching tube Q4, the Q5 of series connection, after inductance L 3 is connected with capacitor C 4, inductance L 3 accesses between switching tube Q2, Q3, capacitor C 4 accesses between switching tube Q4, Q5, in capacitor C 4, is connected with alternating voltage.Wherein, switching tube Q1 adopts IGBT pipe, and upper brachium pontis switching tube Q2, Q4 adopt IGBT pipe, and lower brachium pontis switching tube Q3, Q5 adopt MOSFET pipe.
Wherein, the pass of the output voltage V dc of high-frequency isolation cuk converter and input voltage Vpv is Vdc=Vpv × D/n (1-D), the wherein turn ratio n=n1/n2 of transformer (former limit/secondary), pulse duty factor D=ton/T, ton is ON time, and T is turn-on cycle.The driving signal of the switching tube Q1 of high-frequency isolation cuk converter is the square-wave signal of frequency 15KHz, and the size of the duty ratio D of square-wave signal and input voltage Vpv is inversely proportional to.
Meanwhile, full bridge inverter adopts unipolarity double-edge modulation mode.Upper brachium pontis IGBT switching tube Q2, the Q4 of full bridge inverter, as polarity controller, are operated in power frequency 50Hz, and switch mosfet pipe Q3, the Q5 of lower brachium pontis carry out high frequency switching, control the amplitude of inversion output.
Fig. 1 is hardware circuit of the present utility model basis.Comprise high-frequency isolation cuk converter and rear class inversion full-bridge circuit.
If input voltage Vpv is less than Vdc (being set to 400V), cuk converter increases duty ratio, boost as exporting after Vdc, and for rear class inversion full-bridge circuit provides enough busbar voltages, be that alternating current injects electrical network by DC inverter.
If input voltage Vpv is greater than Vdc, cuk converter reduces duty ratio, and step-down is to export after Vdc, for rear class inversion full-bridge circuit provides enough busbar voltages, is that alternating current injects electrical network by DC inverter.
If input voltage Vpv equals Vdc, cuk converter is adjusted duty ratio, keep isolating output after Vdc, and for rear class inversion full-bridge circuit provides enough busbar voltages, be that alternating current injects electrical network by DC inverter.
The pass of the output voltage V dc of cuk converter and input voltage Vpv is Vdc=Vpv × D/n (1-D), the wherein turn ratio n=n1/n2 of transformer (former limit/secondary), pulse duty factor D=ton/T, ton is ON time, T is turn-on cycle.
Capacitor C 3 adopts the mode of multiple 450V/1000uF alminium electrolytic condenser parallel connection to reach withstand voltage, the capability value of design object, realizes power decoupled function.
Rear class inversion full-bridge circuit is made up of four switching tubes.Adopt unipolarity double-edge modulation mode.Upper brachium pontis IGBT switching tube Q2, the Q4 of full-bridge circuit, as current polarity controller, control the polarity of the sinusoidal ac of inversion output, are operated in power frequency 50Hz.Switch mosfet pipe Q3, the Q5 of lower brachium pontis carry out high frequency switching, control the amplitude of the simple sinusoidal alternating current of inversion output.
The course of work of rear class inverter circuit is: when the positive half cycle of line voltage, and switching tube Q2 conducting, switching tube Q5 high frequency is opened shutoff, and switching tube Q3, Q4 turn-off; When switching tube Q5 conducting, inverter current through switching tube Q2, inductance L 3, AC network, switching tube Q5 to mains supply.When switching tube Q5 turn-offs, grid-connected current through switching tube Q2,, inductance L 3, AC network, diode D4 form continuous current circuit afterflow.
Similarly, when line voltage negative half period, switching tube Q4 conducting, switching tube Q3 high frequency is opened shutoff, and switching tube Q2, Q5 turn-off; When switching tube Q3 conducting, electric current through switching tube Q3, inductance L 3, AC network, switching tube Q4 to mains supply.When switching tube Q3 turn-offs, grid-connected current forms continuous current circuit afterflow through switching tube Q3, inductance L 3, AC network, diode D5.
Fig. 2 is the equivalent circuit diagram of high-frequency isolation type cuk converter in the time of switch conduction.Its course of work is: in switching tube Q1 conduction period, input voltage Vpv is directly loaded in inductance L 1 inductance L 1 is charged, voltage on C1 is directly loaded into the former limit of transformer T1, C1 electric discharge, the electric current that the secondary of transformer T1 induces is to load supplying, and at this moment C1, C2 are in discharge condition.The discharging current of C2 is to load supplying and for inductance L2 energy storage, and fly-wheel diode is because of reverse-biased two cut-offs.
Fig. 3 is the equivalent circuit diagram of high-frequency isolation type cuk converter in the time that switch ends.Its course of work is: between the switching tube Q1 off period, inductance L 1 releases energy, capacitor C 1 charging energy-storing, and charging current senses that by transformer T1 secondary charges to C2, and load current flows through from fly-wheel diode, and energy storage is discharged powering load by inductance L 2.
Fig. 4 is the driving signal of inverter circuit and output voltage, inverter current analogous diagram.Be followed successively by from top to bottom switching tube Q5, Q4, Q3, Q2 drive waveforms, the front voltage waveform of filtering, output grid-connected current waveform.
The full bridge inverter that the utility model provides adopts IBGT, MOSFET hybrid circuit.Because the conduction voltage drop of MOSFET pipe is linear, the in the situation that of underloading, have lower conduction voltage drop, and the conduction voltage drop of IGBT pipe is nonlinear characteristic, has little conduction voltage drop under full load conditions.Adopt IGBT pipe, MOSFET pipe to mix composition inversion full-bridge circuit, there is very high inversion efficiency, no matter under underloading or full load conditions.
More than show and described general principle of the present utility model and principal character and advantage of the present utility model.The technical staff of the industry should understand; the utility model is not restricted to the described embodiments; that in above-described embodiment and specification, describes just illustrates principle of the present utility model; do not departing under the prerequisite of the utility model spirit and scope; the utility model also has various changes and modifications, and these changes and improvements all fall within the scope of claimed the utility model.The claimed scope of the utility model is defined by appending claims and equivalent thereof.
Claims (5)
1. a high-frequency isolation type photovoltaic DC-to-AC converter, it is characterized in that, comprise preceding stage high frequency isolation cuk converter and rear class full bridge inverter, this preceding stage high frequency isolation cuk converter comprises inductance L 1, switching tube Q1, capacitor C 1, transformer T1, capacitor C 2, diode D1, inductance L 2 and capacitor C 3, inductance L 1 one end is connected with input voltage Vpv, the other end is connected with capacitor C 1 one end, capacitor C 1 other end is connected with transformer T1 input, between switching tube Q1 one end access inductance L 1 and capacitor C 1, the other end is connected with transformer T1 input with input voltage Vpv respectively, capacitor C 2 one end are connected with transformer T1 output, one end is connected with output voltage V dc after inductance L 2, output voltage V dc is also connected with transformer T1 output, between diode D1 one end access capacitor C 2 and inductance L 2, the other end is connected with transformer T1 output, capacitor C 3 one end are connected with output voltage V dc, the other end is connected with transformer T1 output, rear class full bridge inverter comprises brachium pontis switching tube Q2, Q3 and lower brachium pontis switching tube Q4, tetra-switching tubes of Q5 and is connected respectively diode D2, D3, D4, the D5 on switching tube Q2, Q3, Q4, Q5, between output voltage V dc, have access to switching tube Q2, the Q3 of series connection and switching tube Q4, the Q5 of series connection, after inductance L 3 is connected with capacitor C 4, inductance L 3 accesses between switching tube Q2, Q3, capacitor C 4 accesses between switching tube Q4, Q5, in capacitor C 4, is connected with alternating voltage.
2. high-frequency isolation type photovoltaic DC-to-AC converter according to claim 1, is characterized in that, switching tube Q1 adopts IGBT pipe, and upper brachium pontis switching tube Q2, Q4 adopt IGBT pipe, and lower brachium pontis switching tube Q3, Q5 adopt MOSFET pipe.
3. high-frequency isolation type photovoltaic DC-to-AC converter according to claim 1, it is characterized in that, the pass of the output voltage V dc of high-frequency isolation cuk converter and input voltage Vpv is Vdc=Vpv × D/n (1-D), the wherein turn ratio n=n1/n2 of transformer (former limit/secondary), pulse duty factor D=ton/T, ton is ON time, and T is turn-on cycle.
4. high-frequency isolation type photovoltaic DC-to-AC converter according to claim 1, is characterized in that, the driving signal of the switching tube Q1 of high-frequency isolation cuk converter is the square-wave signal of frequency 15KHz, and the size of the duty ratio D of square-wave signal and input voltage Vpv is inversely proportional to.
5. high-frequency isolation type photovoltaic DC-to-AC converter according to claim 2, it is characterized in that, upper brachium pontis IGBT switching tube Q2, the Q4 of full bridge inverter, as polarity controller, are operated in power frequency 50Hz, switch mosfet pipe Q3, the Q5 of lower brachium pontis carry out high frequency switching, control the amplitude of inversion output.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201420346740.6U CN203911800U (en) | 2014-06-26 | 2014-06-26 | High-frequency isolated photovoltaic inverter |
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| CN201420346740.6U CN203911800U (en) | 2014-06-26 | 2014-06-26 | High-frequency isolated photovoltaic inverter |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107395041A (en) * | 2017-08-24 | 2017-11-24 | 东莞理工学院 | High conversion efficiency isolated form miniature grid-connected inverter and its control method |
| CN107689738A (en) * | 2016-08-04 | 2018-02-13 | 苏州迈力电器有限公司 | A kind of high frequency photovoltaic DC-to-AC converter |
| CN114244136A (en) * | 2021-12-20 | 2022-03-25 | 上海北漠景观幕墙科技股份有限公司 | Photovoltaic curtain wall system based on photovoltaic building integration |
| CN117713198A (en) * | 2023-12-08 | 2024-03-15 | 广州云酷智能设备有限公司 | Grid-connected inverter control core module and photovoltaic power conversion cabinet |
-
2014
- 2014-06-26 CN CN201420346740.6U patent/CN203911800U/en not_active Expired - Fee Related
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107689738A (en) * | 2016-08-04 | 2018-02-13 | 苏州迈力电器有限公司 | A kind of high frequency photovoltaic DC-to-AC converter |
| CN107395041A (en) * | 2017-08-24 | 2017-11-24 | 东莞理工学院 | High conversion efficiency isolated form miniature grid-connected inverter and its control method |
| CN107395041B (en) * | 2017-08-24 | 2020-06-12 | 东莞理工学院 | High-conversion-efficiency isolated micro grid-connected inverter and control method thereof |
| CN114244136A (en) * | 2021-12-20 | 2022-03-25 | 上海北漠景观幕墙科技股份有限公司 | Photovoltaic curtain wall system based on photovoltaic building integration |
| CN117713198A (en) * | 2023-12-08 | 2024-03-15 | 广州云酷智能设备有限公司 | Grid-connected inverter control core module and photovoltaic power conversion cabinet |
| CN117713198B (en) * | 2023-12-08 | 2024-05-24 | 广州云酷智能设备有限公司 | Grid-connected inverter control core module and photovoltaic power conversion cabinet |
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