An Improved Submodule Capacitor Condition Monitoring Method for Modular Multilevel Converters Considering Switching States  

作　　者：Zan Jia Yongjie Luo Qianggang Wang Niancheng Zhou Yonghui Song Dachuan Yu 

机构地区：[1]State Key Laboratory of Power Transmission Equipment Technology,School of Electrical Engineering,Chongqing University,Chongqing 400044,China [2]China Electric Power Research Institute,Beijing 100192,China

出　　处：《Journal of Modern Power Systems and Clean Energy》2024年第6期2071-2080,共10页现代电力系统与清洁能源学报(英文)

基　　金：This work was supported in part by the Joint Funds of the National Natural Science Foundation of China(No.U22B6006).

摘　　要：The capacitor is one of the most important compo-nents in a modular multilevel converter(MMC).Due to the chemical process and the aging effect,the capacitor is subject to deterioration over time which is usually manifested by a drop in capacitance.To identify the abnormal capacitors and enhance the reliability of MMCs,an improved submodule(SM)capacitor condition monitoring method is proposed in this pa-per.The proposed method estimates the capacitance during each control cycle based on the switching states of SMs,offer-ing advantages such as high accuracy and no adverse influence on the operation of MMCs.Firstly,the aging differences of ca-pacitors in different SMs per arm of MMC are analyzed.Then,the capacitances of SMs that switch on the state are calculated based on the relationship between the capacitor voltage and cur-rent during each control cycle.A data processing algorithm is proposed to improve the accuracy of capacitance estimation.Fi-nally,the simulation and the real-time control hardware-in-the loop test results based on real-time digital simulator(RTDS)show the effectiveness of the proposed method.

关 键 词：Modular multilevel converter(MMC) capacitor condition monitoring data processing submodule switching state 

分 类 号：TM46[电气工程—电器]