CN203747688U - Three-level grid-connected inverter - Google Patents

Three-level grid-connected inverter Download PDF

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Publication number
CN203747688U
CN203747688U CN201420071986.7U CN201420071986U CN203747688U CN 203747688 U CN203747688 U CN 203747688U CN 201420071986 U CN201420071986 U CN 201420071986U CN 203747688 U CN203747688 U CN 203747688U
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China
Prior art keywords
diode
switching tube
emitter
anode
negative electrode
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Expired - Fee Related
Application number
CN201420071986.7U
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Chinese (zh)
Inventor
张海波
王杰
王兆明
孙邦伍
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NANJING GUANYA POWER EQUIPMENT CO Ltd
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NANJING GUANYA POWER EQUIPMENT CO Ltd
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Priority to CN201420071986.7U priority Critical patent/CN203747688U/en
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    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02BCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B10/00Integration of renewable energy sources in buildings
    • Y02B10/70Hybrid systems, e.g. uninterruptible or back-up power supplies integrating renewable energies
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00Energy generation through renewable energy sources
    • Y02E10/50Photovoltaic [PV] energy
    • Y02E10/56Power conversion systems, e.g. maximum power point trackers

Abstract

Disclosed in the utility model is a three-level grid-connected inverter comprising an input direct-current source portion, an alternating-current inversion portion, a redundant circuit portion, and an output circuit portion. According to the scheme, on the basis of the redundant design, the system reliability is improved. When a three-phase inverter works normally and deviation of a bus neutral-point voltage is large at a certain time, the neutral-point voltage can be adjusted rapidly by using a standby three-level bridge arm, thereby preventing the over-voltage breakdown of a switching tube due to neutral-point voltage fluctuation. And when the three-phase invert fails to work, a fault bridge arm can be found out by fault detection; and the fault arm is switched to the three-level bridge arm for application, so that the grid-connected inverter can carry out fault-tolerant operation.

Description

A kind of three level grid-connected inverters
Technical field
The utility model relates to a kind of three-phase grid-connected inverter technology.
Background technology
Along with the continuous increase of photovoltaic system capacity, the requirement of cost, efficiency and reliability to inverter is also more and more higher.In middle low power occasion, non-isolation type three-phase tri-level photovoltaic DC-to-AC converter is high because having voltage withstand class, and harmonic content is little, and volume is little, and efficiency advantages of higher is used widely in grid-connected photovoltaic system.It is lower that the inversion module being made up of discrete power device is compared IGBT module cost, but because switching tube number is more, the reliability of inverter is reduced, and in the time that open circuit or short circuit appear in certain switching tube, whole inverter quits work.And inverter is mainly sold to remote districts or overseas market, this increases the maintenance cost that makes the later stage.Therefore it is significant that, research has the combining inverter of fault tolerance.
Summary of the invention
For problems of the prior art, the utility model provides a kind of three level grid-connected inverters, adopts the Redundancy Design of three-phase four-arm, in the time that the fluctuation of bus capacitor mid-point voltage is larger, by the 4th brachium pontis control neutral point voltage balance, prevent switching tube generation overvoltage and damage; In the time of certain phase switching tube faults of three level grid-connected inverters, the 4th brachium pontis is made in brachium pontis for subsequent use, realizes fault-tolerant operation.
Technical solution of the present utility model is: a kind of three level grid-connected inverters, comprise an input direct-current source part, and an ac converter part, redundant circuit part and output circuit part, adopt Redundancy Design.
Described input direct-current source part comprises: two electrochemical capacitor C d1, C d2rear and input direct-current source U connect dcit is in parallel..
During described ac converter part comprises that three brachium pontis: R are mutually, four switching tube R 1~ R 4press respectively emitter and be connected with collector electrode, diode D 1negative electrode is connected to switching tube R 1emitter, diode D 2anode is connected to switching tube R 4collector electrode, diode D 1anode and diode D 2negative electrode is connected to mid point O after being connected; S mutually in, four switching tube S 1~ S 4press respectively emitter and be connected with collector electrode, diode D 3negative electrode is connected to switching tube S 1emitter, diode D 4anode is connected to switching tube S 4collector electrode, diode D 3anode and diode D 4negative electrode is connected to mid point O after being connected; T mutually in, four switch transistor T 1~ T 4press respectively emitter and be connected with collector electrode, diode D 5negative electrode is connected to switch transistor T 1emitter, diode D 6anode is connected to switch transistor T 4collector electrode, diode D 5anode and diode D 6negative electrode is connected to mid point O after being connected.
Described redundant circuit part comprises: four switching tube N 1~ N presses respectively emitter and is connected with collector electrode, diode D 7negative electrode is connected to switching tube N 1emitter, diode D 8anode is connected to switching tube N 4collector electrode, diode D 7anode and diode D 8negative electrode is connected to mid point O, bidirectional thyristor Q after being connected rtwo ends respectively with switching tube N 2emitter N and switching tube R 2emitter R is connected, bidirectional thyristor Q stwo ends respectively with switching tube N 2emitter N and switching tube S 2emitter S is connected, bidirectional thyristor Q ttwo ends respectively with switching tube N 2emitter N and switch transistor T 2emitter T is connected, energy storage inductor L ntwo ends respectively with switching tube N 2emitter N and relay switch S none end is connected, relay switch S nthe other end is connected with mid point (O).
Described output circuit part comprises: filter inductance L 1~ L 3one end respectively with three-phase output R, S, T point is connected, the other end respectively with filter capacitor C one end and relay switch S a, S b, S cone end is connected, relay switch S a, S b, S cthe other end respectively with three phase network e a, e b, e cbe connected.
The beneficial effects of the utility model are: adopt Redundancy Design, improve the reliability of system; In the time that three-phase inverter normally moves, when bus mid-point voltage is when deviation is larger sometime, can be by three level brachium pontis quick adjustment mid-point voltages for subsequent use, prevent from causing because of mid-point voltage fluctuation the over-voltage breakdown of switching tube, when three-phase inverter breaks down, find out fault brachium pontis by fault detect, three level brachium pontis switchings for subsequent use are used, make the combining inverter can fault-tolerant operation.
Brief description of the drawings
Fig. 1 is the utility model embodiment circuit diagram.
Fig. 2 is the utility model bus capacitor mid-point voltage control flow chart.
Fig. 3 is the utility model system control flow chart.
Embodiment
Below in conjunction with accompanying drawing, by specific embodiment, technical solutions of the utility model are described further.
As shown in Figure 1, Fig. 1 is the utility model embodiment circuit diagram.
Three level grid-connected inverters of the present embodiment, comprise an input direct-current source part, an ac converter part, a redundant circuit part, and output circuit part.
Described input direct-current source part comprises: two electrochemical capacitor C d1, C d2rear and input direct-current source U connect dcit is in parallel..
During described ac converter part comprises that three brachium pontis: R are mutually, four switching tube R 1~ R 4press respectively emitter and be connected with collector electrode, diode D 1negative electrode is connected to switching tube R 1emitter, diode D 2anode is connected to switching tube R 4collector electrode, diode D 1anode and diode D 2negative electrode is connected to mid point O after being connected; S mutually in, four switching tube S 1~ S 4press respectively emitter and be connected with collector electrode, diode D 3negative electrode is connected to switching tube S 1emitter, diode D 4anode is connected to switching tube S 4collector electrode, diode D 3anode and diode D 4negative electrode is connected to mid point O after being connected; T mutually in, four switch transistor T 1~ T 4press respectively emitter and be connected with collector electrode, diode D 5negative electrode is connected to switch transistor T 1emitter, diode D 6anode is connected to switch transistor T 4collector electrode, diode D 5anode and diode D 6negative electrode is connected to mid point O after being connected.
Described redundant circuit part comprises: four switching tube N 1~ N presses respectively emitter and is connected with collector electrode, diode D 7negative electrode is connected to switching tube N 1emitter, diode D 8anode is connected to switching tube N 4collector electrode, diode D 7anode and diode D 8negative electrode is connected to mid point O, bidirectional thyristor Q after being connected rtwo ends respectively with switching tube N 2emitter N and switching tube R 2emitter R is connected, bidirectional thyristor Q stwo ends respectively with switching tube N 2emitter N and switching tube S 2emitter S is connected, bidirectional thyristor Q ttwo ends respectively with switching tube N 2emitter N and switch transistor T 2emitter T is connected, energy storage inductor L ntwo ends respectively with switching tube N 2emitter N and relay switch S none end is connected, relay switch S nthe other end is connected with mid point (O).
Described output circuit part comprises: filter inductance L 1~ L 3one end respectively with three-phase output R, S, T point is connected, the other end respectively with filter capacitor C one end and relay switch S a, S b, S cone end is connected, relay switch S a, S b, S cthe other end respectively with three phase network e a, e b, e cbe connected.
As shown in Figure 2 and Figure 3, Fig. 2 is the utility model bus capacitor mid-point voltage control flow chart; Fig. 3 is the utility model system control flow chart.
When three level grid-connected inverters of the present embodiment normally move, bidirectional thyristor Q r, Q s, Q t, relay switch Sn all disconnects, and three level brachium pontis for subsequent use are not worked.Work as voltage ripple of power network, when three-phase current distortion etc. causes mid-point voltage fluctuation larger, now long by the software adjustment midpoint potential cycle, switching tube bears voltage stress and increases, affect the useful life of switching tube, for guaranteeing to move in safety operation area at device, closing relay switch S n, by energy storage inductor L n, quick centring point current potential regulates.For example,, as electrochemical capacitor C d2voltage is less than electrochemical capacitor C d1voltage, reaches while setting threshold pressure differential two switching tube N 1, N 2conducting, through inductance L n, form Boost circuit, DC power supply U dcto electrochemical capacitor C d2charging, makes electrochemical capacitor C d2current potential rises; Two switching tube N 1, N 2turn-off inductance L nby two switching tube N 3, N 4anti-paralleled diode dump energy is passed to electrochemical capacitor C d2, make electrochemical capacitor C d2current potential rises, because DC source U dcvoltage is constant, thereby makes electrochemical capacitor C d1voltage drop.Same principle, control switch pipe N 3, N 4, through inductance L 2, can be to electrochemical capacitor C d1charging; When mid-point voltage fluctuation hour, brachium pontis for subsequent use is not worked, and normal inverter circuit is not affected.
In the time that three-phase inverter system breaks down, system protection action, relay switch S a, S b, S cdisconnect, system restarts under the pattern from guipure zero load, by the voltage u to three-phase outlet side a, u b, u ccarry out failure diagnosis with mid-point voltage O, cut off the brachium pontis damaging, brachium pontis for subsequent use is come into operation.For example, R phase brachium pontis breaks down, lockout switch pipe R 1~ R 4drive waveforms, bidirectional thyristor Q rconducting, three level brachium pontis for subsequent use are made in A phase brachium pontis, switching tube N 1~ N 4work, regulates three-phase output voltage u a, u b, u c, when with line voltage e a, e b, e cwith frequently, homophase, during with width, relay switch S a, S b, S cclosure, three-phase grid-connected inverter normal operation, has improved the reliability of inverter.
The foregoing is only the present invention's preferred embodiment; not limit practical range of the present invention with this, all persons that is familiar with technique, use principle of the present invention and technical characterictic; various changes and the decoration done, within all should being covered by the protection category that these claims define.

Claims (1)

1. three level grid-connected inverters, is characterized in that: comprise an input direct-current source part, and an ac converter part, redundant circuit part and output circuit part, adopt Redundancy Design;
Described input direct-current source part comprises: two electrochemical capacitor C d1, C d2rear and input direct-current source U connect dcin parallel;
During described ac converter part comprises that three brachium pontis: R are mutually, four switching tube R 1~ R 4press respectively emitter and be connected with collector electrode, diode D 1negative electrode is connected to switching tube R 1emitter, diode D 2anode is connected to switching tube R 4collector electrode, diode D 1anode and diode D 2negative electrode is connected to mid point O after being connected; S mutually in, four switching tube S 1~ S 4press respectively emitter and be connected with collector electrode, diode D 3negative electrode is connected to switching tube S 1emitter, diode D 4anode is connected to switching tube S 4collector electrode, diode D 3anode and diode D 4negative electrode is connected to mid point O after being connected; T mutually in, four switch transistor T 1~ T 4press respectively emitter and be connected with collector electrode, diode D 5negative electrode is connected to switch transistor T 1emitter, diode D 6anode is connected to switch transistor T 4collector electrode, diode D 5anode and diode D 6negative electrode is connected to mid point O after being connected;
Described redundant circuit part comprises: four switching tube N 1~ N 4press respectively emitter and be connected with collector electrode, diode D 7negative electrode is connected to switching tube N 1emitter, diode D 8anode is connected to switching tube N 4collector electrode, diode D 7anode and diode D 8negative electrode is connected to mid point O, bidirectional thyristor Q after being connected rtwo ends respectively with switching tube N 2emitter N and switching tube R 2emitter R is connected, bidirectional thyristor Q stwo ends respectively with switching tube N 2emitter N and switching tube S 2emitter S is connected, bidirectional thyristor Q ttwo ends respectively with switching tube N 2emitter N and switch transistor T 2emitter T is connected, energy storage inductor L ntwo ends respectively with switching tube N 2emitter N and relay switch S none end is connected, relay switch S nthe other end is connected with mid point O;
Described output circuit part comprises: filter inductance L 1~ L 3one end respectively with three-phase output R, S, T point is connected, the other end respectively with filter capacitor C one end and relay switch S a, S b, S cone end is connected, relay switch S a, S b, S cthe other end respectively with three phase network e a, e b, e cbe connected.
CN201420071986.7U 2014-02-20 2014-02-20 Three-level grid-connected inverter Expired - Fee Related CN203747688U (en)

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106329561A (en) * 2015-06-17 2017-01-11 台达电子工业股份有限公司 Solar inverter grid connected system and three-phase grid connected method
CN108155657A (en) * 2018-01-02 2018-06-12 许继电源有限公司 Energy accumulation current converter and its main circuit topological structure and balance control method
CN108832661A (en) * 2018-07-13 2018-11-16 华南师范大学 A kind of grid-connected photovoltaic system of more redundancy-types
CN110022079A (en) * 2019-04-29 2019-07-16 合肥工业大学 A kind of design method of T-type three-level current transformer DC bus capacitor capacitance
CN111669069A (en) * 2020-06-02 2020-09-15 国网山西省电力公司电力科学研究院 Control method of AC/DC bus interface converter with midpoint potential fluctuation suppression function
CN112350587A (en) * 2020-10-30 2021-02-09 中车永济电机有限公司 Traction-assisted converter and device

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106329561A (en) * 2015-06-17 2017-01-11 台达电子工业股份有限公司 Solar inverter grid connected system and three-phase grid connected method
CN106329561B (en) * 2015-06-17 2018-12-11 台达电子工业股份有限公司 Solar inverter grid-connected system and three-phase grid method
CN108155657A (en) * 2018-01-02 2018-06-12 许继电源有限公司 Energy accumulation current converter and its main circuit topological structure and balance control method
CN108832661A (en) * 2018-07-13 2018-11-16 华南师范大学 A kind of grid-connected photovoltaic system of more redundancy-types
CN110022079A (en) * 2019-04-29 2019-07-16 合肥工业大学 A kind of design method of T-type three-level current transformer DC bus capacitor capacitance
CN110022079B (en) * 2019-04-29 2020-03-31 合肥工业大学 Design method for capacitance value of direct-current side capacitor of T-type three-level converter
CN111669069A (en) * 2020-06-02 2020-09-15 国网山西省电力公司电力科学研究院 Control method of AC/DC bus interface converter with midpoint potential fluctuation suppression function
CN112350587A (en) * 2020-10-30 2021-02-09 中车永济电机有限公司 Traction-assisted converter and device

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CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20140730

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