基于载波移相调制的MMC控制策略研究及仿真

为研究模块化多电平换流器(MMC)的控制策略,首先介绍了MMC的拓扑结构及其基本工作原理,在对比其他调制策略的基础上,综合考虑该新型换流器的结构特点以及需要实现的电平数,选取了载波移相正弦脉宽调制策略(carrier phase-shifted PWM,CPS-PWM);接着根据子模块能量均分和电压均衡两种原则,针对载波移相调制策略,选择了一种子模块电容均压策略,以确保子模块电压稳定在同一水平;最后通过仿真结果验证所设计的控制策略的有效性。

Research and Simulation of MMC Control Strategy Based on Carrier Phase Shift Modulation

In order to study the control strategy of modular multilevel converter(MMC), this paper introduced the topological structure and the basic working principle of MMC firstly. Secondly, comparing with other modulation strategies, considering the structure characteristics of the new converter and the number of levels needed to be realized, the carrier phase shifted sinusoidal pulse width modulation(CPS-SPWM)scheme suitable for modular multi-level converter was selected. Thirdly, according to the two principles of energy equalization and voltage equalization of sub-modules and the corresponding modulation strategy, a capacitor voltage balance control strategy of sub-modules was proposed to ensure that the capacitor voltage of each sub-module fluctuated in a stable range. Finally, simulation results verified the effectiveness of the proposed strategy.