Abstract：The pre-charging process of modular multilevel converter (MMC) could be divided into uncontrolled pre-charging process and controlled pre-charging process. By comparing the uncontrolled pre-charging process with the uncontrolled rectifying process of 3-phase full bridge, the increase process of sub-module capacitor voltage was fully analyzed. Furthermore, a simple and effective unlock control strategy was proposed for the controlled charging process. The proposed strategy could quickly charge all the sub-module capacitors to the voltage required for the steady state operation of MMC. With the proposed unlock strategy, no indicated pre-charging controller was required, and the voltage fluctuation of sub-module capacitor could be significantly reduced when the converter switching to the normal operation after pre-charging. The decrease of the voltage fluctuation could effectively reduce the voltage impact of the capacitors and thus extend the lifespan of the sub-module capacitors. Finally, a detailed simulation model of a double terminal MMC was built on PSCAD/EMTDC to verify the effectiveness of the developed control strategy.
标题：模块化多电平变换器预充电控制策略
title:Pre-Charging Control Strategy for Modular Multilevel Converter
作者：姚骏, 谭义, 赵磊
authors:YAO Jun , TAN Yi , ZHAO Lei
关键词：模块化多电平变换器(MMC),预充电,解锁控制,电容电压波动,
keywords:modular multilevel converter(MMC),pre-charging,unlock control,capacitor voltage fluctuation,
