Grid-connected inverter circuit and control method thereof

An inverter circuit and inverter technology, applied in electrical components, single grid parallel feeding arrangement, AC power input conversion to DC power output, etc., can solve the complex structure of grid-connected inverters and high output harmonic content. problem, to achieve the effect of simple structure and reducing output harmonic content

Active Publication Date: 2016-09-28
ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] Based on this, it is necessary to provide a grid-connected inverter circuit with a simple structure and low output harmonic content for the problems of complex structure and high output harmonic content of general grid-connected inverters.

Method used

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  • Grid-connected inverter circuit and control method thereof
  • Grid-connected inverter circuit and control method thereof
  • Grid-connected inverter circuit and control method thereof

Examples

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Effect test

example 1

[0035]Example 1, N=3, the inverter is a full-bridge inverter, the N+1-port transformer is a high-frequency self-coupling N+1-port transformer, the 2N-phase rectifier is a 2N-phase full-bridge rectifier, and the 2N+1-port inverter includes 2N+1 switching tubes, that is, in this specific embodiment, the grid-connected inverter circuit is a high-frequency isolated seven-level autotransformer grid-connected inverter single-phase circuit.

[0036] Such as figure 2 As shown, the high-frequency isolated seven-level autotransformer grid-connected inverter single-phase circuit includes a DC power supply 600, a full-bridge inverter 100, a high-frequency autotransformer N+1 port transformer 200, and a 2N-phase full-phase inverter connected in sequence. Bridge rectifier 300, 2N voltage dividing capacitors 400, 2N+1-terminal single-phase inverter 500, wherein the DC power supply 600 is connected to the two bridge arms on the DC side of the mid-high frequency half-bridge inverter part of t...

Embodiment 2

[0037] Embodiment 2, N=3, the inverter is a full-bridge inverter, the N+1-port transformer is a high-frequency auto-coupling N+1-port transformer, the 2N-phase rectifier is a 2N-phase full-bridge rectifier, and the 2N+1-port inverter The inverter is connected to the external three-phase AC system, and the 2N+1 terminal inverter includes 3*(2N+1) switching tubes, that is, in this specific embodiment, the grid-connected inverter circuit is a high-frequency isolated seven-level inverter circuit Autotransformer grid-connected inverter three-phase circuit.

[0038] Such as image 3 As shown, the high-frequency isolated seven-level autotransformer grid-connected inverter three-phase circuit is the same as the above-mentioned embodiment of a seven-level single-phase inverter circuit (embodiment 1 figure 2 ) is that the provided 2N+1 (seven)-terminal single-phase inverter is replaced by a 2N+1 (seven)-terminal three-phase inverter 100, and the three-phase outputs A, B, and C are con...

Embodiment 3

[0039] Embodiment 3, N=5, the inverter is a full-bridge inverter, the N+1-port transformer is a high-frequency self-coupling N+1-port transformer, the 2N-phase rectifier is a 2N-phase full-bridge rectifier, and the 2N+1-port inverter The inverter is connected to the external three-phase AC system, and the 2N+1 terminal inverter includes 2N+1 switch tubes, that is, in this specific embodiment, the grid-connected inverter circuit is a high-frequency isolated thirteen-level autotransformer Voltage grid-connected inverter single-phase circuit.

[0040] Such as Figure 4 As shown, the high-frequency isolated eleven-level autotransformer grid-connected inverter single-phase circuit and the seven-level single-phase inverter circuit (Example 1 figure 2 ) is that two pairs of ports are added to the output terminal of the secondary side of the high-frequency autotransformer (N changes from 3 to 5), and then two full-bridge rectifiers are respectively connected to output 4 more DC leve...

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Abstract

The invention provides a grid-connected inverter circuit and a control method thereof. The grid-connected inverter circuit comprises an inverter, an (N+1)-port transformer, a 2N-phase rectifier, 2N voltage dividing capacitors and a (2N+1)-end inverter; direct-current voltage is subjected to high-frequency inversion via the inverter to generate high-frequency square wave, the high-frequency square wave passes through the (N+1)-port transformer to boost the voltage into voltage of N voltage levels, the square wave of the N voltage levels is respectively rectified to form voltage of 2N different levels, the voltage of 2N different levels and a zero potential grounding point form (2N+1) level branches, the levels are isolated by the capacitors connected in series longitudinally and charge the capacitors, and the (2N+1) level branches are respectively connected with the (2N+1)-end inverter. The whole circuit adopts multi-level inversion, so that the content of output harmonic is greatly reduced, additional high-capacity filters are not needed, and the structure is simple.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a grid-connected inverter circuit and a control method thereof. Background technique [0002] In recent years, with the development of photovoltaic power generation, large-capacity energy storage devices, electric vehicles, and flexible DC transmission technology, there is an increasing need for a grid-connected inverter that is safe, efficient, low-cost, and has low output harmonic content. [0003] Traditional grid-connected inverters are divided into isolated and non-isolated types. Non-isolated types generate common-mode leakage currents to ground and tend to inject DC components into the grid. Isolated grid-connected inverters are divided into two types: power frequency and high frequency, both of which first convert DC to AC and then step up the voltage through a transformer. However, power frequency transformers have disadvantages such as large volume and weight...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/483H02M7/537H02J3/38
CPCH02J3/38H02M7/483H02M7/537
Inventor 文安卢亮宇魏承志饶宏曾勇刚牟敏杨俊权赵曼勇许树楷刘琨黄维芳金鑫
Owner ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD
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