Optimization control method of multi-section zero sequence voltage approximation HANPC multi-level converter

Abstract

The invention discloses an optimization control method of a multi-section zero sequence voltage approximation HANPC multi-level converter. The method comprises the following steps of: modulating an HANPC multi-level converter according to a corresponding relationship between different switch states and output levels in the HANPC multi-level converter; determining a corresponding relation between decoupling control and duty ratio adjustment of capacitor voltages of a suspension capacitor and a direct-current side midpoint capacitor of the HANPC multi-level converter; establishing constraint conditions between the zero-sequence voltage and the voltage controller output of the suspension capacitor, the voltage controller output of the direct-current side midpoint capacitor and the linear adjustment range of the zero-sequence voltage; and calculating a zero-sequence voltage value by adopting a sectional type zero-sequence voltage approximation method based on the constraint condition. According to the invention, the zero-sequence voltage value can be solved more accurately, the effects of improving the working efficiency of the converter and reducing the volume of the upper bus and the lower bus are achieved, the constraint of the linear modulation range is considered, overmodulation can be effectively avoided, and the situation of level jump is reduced.

Description

technical field [0001] The invention relates to the technical field of converters, in particular to an optimal control method for a HANPC multilevel converter with multi-stage zero-sequence voltage approximation. Background technique [0002] In the prior art, there are many different ways of dealing with the topological structure problem of Active Neutral Point Clamped (ANPC). Specifically as follows: [0003] (1) Add the H-bridge to the ANPC topology to double the output level of the ANPC, but the H-bridge switching tube will bear the voltage stress of the entire DC bus, and the device inconsistency will increase. [0004] (2) The switch capacitor is introduced into the ANPC topology to increase the output level, but it does not essentially solve the problem of uneven switching stress on the device. [0005] (3) A new type of hybrid active neutral point clamped (Hybrid Active Neutral Point Clamped, HANPC) multilevel converter is proposed, which can reduce the topological...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide an optimized control method for HANPC multi-level converters with multi-stage zero-sequence voltage approximation to solve the problem of large zero-sequence voltage solution errors, resulting in frequent phase voltage level jumps and up and down The problem of excessive bus capacitor ripple

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