基于级联H桥换流器的APF-STATCOM的控制与调制

有源滤波器(APF)和静止同步补偿器(STATCOM)在电力系统应用中都是独立开来,分别进行谐波抑制和无功补偿。将APF和STATCOM功能结合起来,以级联H桥换流器构成APF-STATCOM装置,同时实现无功补偿和谐波抑制。在分析级联H桥APF-STATCOM拓扑及其工作原理的基础上,提出了一种简单有效的控制策略;针对级联H桥换流器各子模块间的电容电压均衡问题,采用最近电平逼近调制(NLM)并提出了一种适用于级联H桥换流器的电容电压均衡控制策略。利用PSCAD/EMTDC对36级联H桥APF-STATCOM进行了建模仿真,结果验证了该控制策略和电容电压均衡控制策略的可行性和有效性,并表明所提出的电容电压均衡策略能有效避免H桥模块IGBT不必要的频繁开关,减少器件的开关频率。

Control and modulation for APF-STATCOM based on cascaded H-bridge converter

Active power filter (APF) and static synchronous compensator (STATCOM) are indispensable elements in power system. APF can be used to suppress the harmonics, while STATCOM can be used to compensate reactive power. In this paper, the functions of APF and STATCOM are combined in a single unit by controlling a three-phase cascaded H-bridge converter, i.e. APF-STATCOM. This paper introduces topology and working principle of cascaded H-bridge APF-STATCOM and puts forward a control strategy. In order to balance DC capacitor voltages of cascaded H-bridge converter, balancing control strategy for cascaded H bridge converters based on nearest voltage level modulation (NLM) is proposed. 36 cascaded H-bridge APF-STATCOM model is set up in PSCAD/EMTDC. And by the simulation, the feasibility and effectiveness of control strategy and balance control strategy are verified. The proposed capacitor voltage balancing strategy can avoid unnecessary frequent switch of H bridge module IGBT.