Modularization multi-level converter redundancy fault-tolerant control method

Abstract

The invention provides a modularization multi-level converter redundancy fault-tolerant control method. According to the method, an inverter controller is arranged on the alternating current side of a modularization multi-level converter; redundancy fault-tolerant model prediction control is carried out on the modularization multi-level converter, wherein the redundancy fault-tolerant model prediction control is composed of three control objects of alternating current tracking, sub-module capacitive voltage equalization and circulation suppression; each control object defines an objective function to calculate all possible switching state objective function values under the corresponding objective function; an alternating current tracking objective function and a sub-module capacitive voltage equalization objective function calculate numerical values under all switching states of MMC; a circulation suppression objective function calculates numerical values under all circulation suppression compensation levels; the minimum value of the objective functions is selected; the switching state corresponding to the minimum value of the objective functions is recorded; and the switching state is input into the MMC and is used as the switching state of the MMC of next moment. Circulation suppression and sub-module capacitive voltage equalization of the modularization multi-level converter in the case of redundancy fault-tolerance are realized.

Description

technical field [0001] The invention relates to the technical field of converters, in particular to a redundant fault-tolerant control method for converters. Background technique [0002] The topological structure of voltage source converter is mainly divided into two-level and three-level forms, which are widely used in DC transmission projects, but this type of topology has disadvantages such as high switching frequency, series dynamic voltage equalization, and large harmonic content. . Compared with the traditional two-level voltage source converter, the modular multilevel converter (MMC) proposed by German scholars Lesnicar and R.Marquardt has high modularity, low loss, strong scalability, and output The waveform quality is good, and it has the advantages of fault ride-through capability. In 2010, the converter of this topology was used for the first time in the US "Trans Bay Cable" project put into operation by Siemens. In recent years, modular multilevel converters ...

AI Technical Summary

Problems solved by technology

Although the first solution realizes the symmetrical operation of the system, there are many sub-modules that need to be bypassed, resulting in unstable operation of the converter

Although the second solution greatly reduces the risk of bypassing the normal working sub-modules, it will cause asymmetric operation between the bridge arms of the converter

However, adopting the second scheme will bring many influences to the MMC, such as changes in the circulating current components, unbalanced sub-module capacitor voltages, etc.

Images