模块化多电平变流器子模块电容老化状态在线监测及均衡策略  

On-line monitoring and balancing strategy for capacitor aging in modular multilevel converter

作　　者：蒲清昕 秦亮[1] 王庆[2] 刘开培[1] Pu Qingxin;Qin Liang;Wang Qing;Liu Kaipei(School of Electrical Engineering and Automation,Wuhan University,Wuhan 430072,China;Equipment Management Department,State Grid Corporation of China,Beijing 100032,China)

机构地区：[1]武汉大学电气与自动化学院,武汉430072 [2]国家电网公司设备管理部,北京100032

出　　处：《电测与仪表》2022年第7期193-200,共8页Electrical Measurement & Instrumentation

基　　金：国家自然科学基金面上项目(51977160)。

摘　　要：模块化多电平变流器(Modular Multilevel Converter, MMC)中电容老化程度高的子模块投切频率更大、损耗更高,危害子模块的安全运行。针对这个问题提出一种用于MMC的电容老化状态在线监测及均衡策略。通过电容电压变化与电容值的关系对电容老化状态进行在线监测,测量子模块电容间的相对值;根据测量的结果,在排序中引入虚拟电容电压,降低老化严重子模块的开关频率,延缓电容的使用寿命;仿真结果表明文中所提策略能够在不影响电容电压平衡的前提下有效降低老化严重子模块的开关频率,而且不用对子模块单独加装额外传感设备、不使用复杂算法,适用于子模块较多的场合。The more serious sub-module capacitor aging in the modular multilevel converter(MMC) will increase the switching frequency and increase the loss of the converter valve, which will damage the safe operation of the inverter. Aiming at this problem, this paper proposes an on-line monitoring and balancing strategy of capacitor aging state for MMC. Firstly, the capacitance aging state is monitored online by the relationship between the capacitance voltage change and the capacitance value, and the relative value between the sub-module capacitances is measured. Then, according to the measurement result, the virtual capacitor voltage is introduced in the sorting to reduce the switching frequency of the aging severe sub-module and delay the service life of the capacitor. The simulation results show that the proposed strategy can effectively reduce the switching frequency of the aging sever sub-module without affecting the capacitor voltage balance. This method does not need to add additional equipment to the sub-module, does not use complex algorithms, which can be applied in many occasions where there are many sub-modules.

关 键 词：模块化多电平变流器 电容老化 在线监测 老化状态均衡 

分 类 号：TM46[电气工程—电器]