基于模块化多电平换流器的电机低频控制策略  

A Control Strategy of Modular Multilevel Converters for Motor in Low Frequency Operation

作　　者：谭风雷 陈昊 张兆君 朱超 张建忠[2] TAN Fenglei;CHEN Hao;ZHANG Zhaojun;ZHU Chao;ZHANG Jianzhong(State Grid Jiangsu Electric Power Company,Nanjing 210000,China;School of Electrical Engineering,Southeast University,Nanjing 210096,China)

机构地区：[1]国网江苏省电力有限公司,江苏南京210000 [2]东南大学电气工程学院,江苏南京210096

出　　处：《华北电力大学学报（自然科学版）》2018年第6期44-51,共8页Journal of North China Electric Power University：Natural Science Edition

基　　金：国家自然科学基金资助项目(51577025)

摘　　要：针对模块化多电平换流器(MMC)低频运行时,子模块电容电压显著波动问题,提出了一种低频控制策略,该策略主要是通过注入高频零序电压和高频环流的方式来提高子模块电容电压的波动频率,从而抑制电容电压波动。将电容伏安特性和开关函数相结合,分析了子模块电容电压波动情况,在此基础上推导了低频控制方法,同时结合MMC的控制原理,将该方法推广到电机调速领域,并给出了算法的具体实现过程。最后从电机启动和低频运行两个方面进行了仿真研究,结果表明本文所提出的方法有效抑制了子模块电容电压波动,能够保证系统安全、可靠地运行于低频环境,从而验证了方法的有效性与可行性。To solve the problem of voltage fluctuation of capacitors in sub-modules when modular multilevel converters(MMC)operates at low frequency,a control strategy for low frequency is proposed.The strategy aims to increase floating capacitors’fluctuation frequency by injecting high frequency zero-sequence voltage and circulating current,thus restraining voltage fluctuation of floating capacitors.The voltage fluctuation of floating capacitors was analyzed by combining voltage-ampere characteristics of capacitors with switching function.Based on which,three different methods(sinusoidal-wave,square-wave and duty-cycle)of the control strategy for low frequency were deduced and generalized to AC drive field by combining with the control principle of MMC.Specific algorithm process was put forward at the same time.Finally,the authors carried out simulation researches on both motor startup and low frequency operation.Results show that the method can effectively restrain voltage fluctuation of floating capacitors and ensure safe and reliable operation of the system at low frequency,which verifies the proposed methods.

关 键 词：模块化多电平换流器 电容电压波动 低频控制策略 电机启动 低频运行 

分 类 号：TM46[电气工程—电器]