一种模块化多电平变流器的变频控制策略  

A Control Strategy of Modular Multilevel Converter for Variable Frequency Operation

作　　者：于洋[1] 葛琼璇[1] 雷鸣[1] 王晓新[1] 李耀华[1] 

机构地区：[1]电力电子与电气驱动重点实验室(中国科学院电工研究所),北京市海淀区100190

出　　处：《电网技术》2016年第9期2780-2788,共9页Power System Technology

基　　金：国家863高技术基金项目(2014AA052602)~~

摘　　要：模块化多电平变流器作为一种新型的多电平变流器拓扑,具有无需隔离变压器、谐波含量低、便于四象限运行等优点。然而,由于模块电容电压低频波动较大,到目前为止,模块化多电平拓扑在变频调速领域还没有得到广泛应用。针对这一问题,提出了一种在桥臂共模电流和输出共模电压中加入高频方波分量的低频控制策略,同时提出了一种基于基频电流注入的高频控制策略,并研究了控制算法的切换问题。在此基础上,提出了一种模块化多电平逆变器宽频率范围运行的控制策略,该策略能减小电容电压的低频波动,维持模块电容电压的平衡,保证电机平稳启动并稳定运行。最后,仿真和实验结果验证了所提控制策略的正确性和有效性。Modular multilevel converter （MMC）, as a new type of multi-level topology, provides advantages such as elimination of isolation transformer, low harmonic content and convenience in operating in four quadrants. However, due to low frequency fluctuation of capacitor voltage, until now modular multilevel topology has not been applied in motor speed regulation fields. Therefore, this paper presents a low frequency control scheme, which adds high-frequency square-wave component to arms’ common-mode current and output voltage simultaneously. Meanwhile, a high frequency control scheme is put forward and control strategy switching is delved into. Based on these, control strategy for modular multilevel inverter over wide frequency range is obtained to reduce capacitor voltage fluctuation and make motor start and work stable. At last, simulation and experiment results demonstrate correctness and effectiveness of the proposed control scheme.

关 键 词：模块化多电平 解耦控制 共模电流 变频控制 

分 类 号：TM76[电气工程—电力系统及自动化]