Micro-grid multi-inverter parallel voltage unbalanced compensation method

A voltage unbalanced, multi-inverter technology, applied in the direction of multi-phase network asymmetry reduction, multi-phase network elimination/reduction of asymmetry, etc., can solve the problem of increasing system hardware costs, exceeding the rated value of power quality regulators, reducing system reliability issues

Active Publication Date: 2013-10-23
HUNAN UNIV
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  • Abstract
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  • Application Information

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Problems solved by technology

However, when the load is seriously unbalanced, the magnitude of the compensation current injected by the parallel power quality conditioner will increase sharply, even exceeding the rated value of the power qua

Method used

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  • Micro-grid multi-inverter parallel voltage unbalanced compensation method
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  • Micro-grid multi-inverter parallel voltage unbalanced compensation method

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Embodiment Construction

[0033] Such as figure 1 As shown, the multi-inverter parallel system in an embodiment of the present invention includes several parallel-connected three-phase inverters, and the three-phase inverter includes a DC micro-source, a three-phase inverter full-bridge circuit, an LC filter circuit, and a sampling conditioning circuit , DSP controller, drive protection circuit. The DC micro-source, the three-phase inverter full-bridge circuit, and the LC filter circuit are connected in sequence, and the LC filter circuit is connected to the AC bus through the line impedance; the sampling conditioning circuit is connected to the LC filtering circuit; the DSP controller is connected to the sampling conditioning circuit and the drive protection circuit. Connection, the three-phase full-bridge inverter circuit includes three parallel bridge arms, a single bridge arm is composed of two fully-controlled power devices connected in series, and the drive protection circuit is connected to six ...

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Abstract

The invention discloses a micro-grid multi-inverter parallel voltage unbalanced compensation method. The method relates to an unbalanced compensation ring, a power droop control ring and a voltage and current ring. On the basis of traditional power droop control, three-phase negative sequence voltages and currents are detected, the negative sequence reactive conductance Q-G unbalanced droop control ring is introduced, directive current reference values are synthesized and revised, and then unbalanced compensation of micro-grid voltage is achieved. Through P-f, Q-E and Q-G droop control, distributed power inverters can independently adjust and output fundamental wave frequency, voltage amplitude and unbalanced compensation conductance, and therefore active and reactive equilibrium distribution can be achieved among the inverters. Quasi-resonance PR control is adopted by the voltage and current control ring, astatic control of the voltage is achieved, dead-beat control is adopted, and then accurate control of currents in an inner ring is achieved. According to the method, the three-phase inverters in a micro-grid possess the unbalanced compensation capacity, and therefore micro-grid three-phase voltage balance is maintained.

Description

technical field [0001] The invention relates to the technical fields of new energy distributed power generation, microgrid operation and control, in particular to a method for compensating voltage unbalance in parallel with multiple inverters in a microgrid. Background technique [0002] As an effective carrier of distributed generation (DG), the microgrid is mainly composed of power electronic conversion devices, energy storage devices, protection and load control equipment, and can operate in both island and grid-connected states. It is a distributed generation of DG. An effective way to access the large power grid is also an important part of the smart grid. [0003] However, in a low-voltage microgrid composed of three-phase inverters, three-phase load asymmetry often exists, which will lead to a three-phase imbalance in the supporting voltage of the microgrid, resulting in a large energy loss and affecting the microgrid system. stability. When the voltage of the point...

Claims

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Application Information

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IPC IPC(8): H02J3/26
CPCY02E40/50
Inventor 罗安陈燕东周洁周乐明黄媛陈智勇彭自强龙际根王明玥王华军
Owner HUNAN UNIV
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