基于模块化级联多电平变换器的STATCOM研究

Research on the MMCC-based STATCOM

研究了基于模块化级联多电平变换器(MMCC)的静止同步补偿器(STATCOM),对其主电路拓扑、工作原理、调制技术和控制策略进行了研究。采用功率解耦控制算法对交流侧无功功率补偿进行控制,并根据功率守恒原理,分析了直流侧电压不平衡因素,引入了分布式直流侧电压控制算法。直流侧控制算法分为上、下层控制部分,其中上层控制部分对所有模块直流侧电压的平均值平衡进行控制,下层控制部分则对各个子模块单元的直流侧电压进行控制。最后,在一台以VME控制箱为核心控制器的3级MMCC系统上对控制策略进行了验证,实验结果表明了算法的可行性。

The main circuit topology, principle, modulation method and the control strategy of the static synchronous eompensator（STATCOM） based on modular multilevel cascaded converter（MMCC） are studied.Power decoupling control algorithm is introduced to control the reactive power compensation of AC side.According to the principle of power conservation, the unbalance factor of the DC side is analyzed.Then the distibuted DC-vohage control algorithm is proposed which is divided into upper and lower control sections.The average balance of all modules DC voltage is controlled by the upper control section while the DC voltage of each module unit is controlled by the lower section.Finally,the validity of these algorithms are verified by the experimental results which implement on a 3-cascade system controlled by VME control system.