模块化多电平换流器子模块故障特性和冗余保护

对模块化多电平换流器（MMC）的基本工作原理进行了阐述,分析了MMC中子模块的几种常见故障原因,指出了单个子模块故障会引发直流电压和直流电流的振荡,最终将导致换流器停运。对级联H桥多电平换流器几种常见的子模块故障冗余保护方案进行了比较,在此基础上提出了适合MMC的子模块故障冗余保护方法。该方法将少量冗余子模块置于热备用...

Redundancy Protection for Sub-module Faults in Modular Multilevel Converter

The operation mechanism of modular multilevel converter(MMC) is described.Different kinds of sub-module faults in MMC are analyzed,which may cause the oscillations of DC voltage and current and finally cause the outage of the converter.Different redundancy protection methods(RPMs) to deal with sub-module faults in cascaded H-bridge converter are compared,and then a new RPM suitable for sub-module faults in MMC is proposed.In this method,one or few redundant sub-modules are put in hot stand-by state in order to replace fault sub-module rapidly,while the others are in cold stand-by blocking state so as to protect the insulated gate bipolar translators(IGBTs) from current flowing in them.Time-domain simulation results show that the proposed RPM enables MMC based voltage source converter based high voltage direct current(VSC-HVDC) system to recover from sub-module faults without interruptions of power delivery.