Control system and control method of three-phase four-bridge-arm inverter based on phase-locked loop sequencing

Abstract

The invention discloses a control system and a control method of a three-phase four-bridge-arm inverter based on phase-locked loop sequencing. The control method comprises the following steps: firstly, decomposing three-phase asymmetric voltage and inductive current output by the three-phase four-bridge-arm inverter into positive sequence, negative sequence, zero sequence voltage and current components by adopting a symmetric component method; secondly, performing proper coordinate rotation transformation on the extracted negative-sequence and zero-sequence components; converting the negative-sequence and zero-sequence components into negative-sequence and zero-sequence components under a positive-sequence coordinate system; then, using synchronous rotation coordinate transformation basedon a phase-locked loop; converting the extracted positive-sequence, negative-sequence and zero-sequence components into a dq0 rotating coordinate, then performing inverse Park and inverse Clark conversion on the three-sequence components subjected to double-loop PI control, and superposing the three-sequence components to obtain an instantaneous reference voltage of a three-dimensional space vector modulation algorithm. According to the method, the conversion algorithm of the negative sequence component of the traditional double-synchronous rotating coordinate system is effectively simplified,and the adjustment time is reduced, so that the system tends to be stable more quickly.

Description

technical field [0001] The invention belongs to the field of power grid technology control, and relates to a phase-locked loop-based sequenced three-phase four-arm inverter control system and a control method. Background technique [0002] With the development of computer technology, network technology, and communication technology, various electrical equipment such as electric vehicles have put forward higher and higher requirements for power quality, and ensuring the symmetrical output of three-phase voltage is the most basic requirement for it. The vehicle-mounted UPS is mainly used to supply power to the equipment on the vehicle that needs AC power supply. The purpose is to solve the problem of no AC mains power on the vehicle, so that various equipment can be used for long-distance driving. However, the unbalanced three-phase voltage brought by the three-phase unbalanced load in the system is the main problem faced by the independent power supply system. In order to ef...

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Problems solved by technology

[0003] There are also many modulation strategies for the three-phase four-arm structure, such as the third harmonic injection method, current tracking control method, three-dimensional space vector modulation method based on the αβγ coordinate system, etc., these control methods can be effective to a certain extent Solve the three-phase unbalanced voltage problem caused by the three-phase unbalanced load, but at the same time, it also has problems such as large harmonic content of the output load current, poor adaptability of control parameters, and too complicated algorithm

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