链式STATCOM直流电容电压分布式控制

DC Capacitor Voltage Distributed Control System for Cascaded Multilevel STATCOM

本文研究了一种链式静止同步补偿器(STATCOM)直流电压分布式控制方案,主链节直流电压由中央控制器控制,从链节直流电压由本链节控制器控制。该方案只需将主链节直流电压上传至中央控制器,并且中央控制器下传给各链节的调制波均相同,因此可以简化通信系统设计。当链节数改变时,中央控制算法几乎不需改变,便于链节扩展。但链节之间未交换直流电压信息导致直流电压控制调节量之和不为零,从而引起各从链节直流电压控制算法的相互耦合,这种耦合作用会恶化系统动态性能,甚至可能引起不稳定。分析指出在主链节直流电压闭环控制作用下,这种耦合作用会被抑制。通过揭示直流电压控制调节量和链节损耗差异间的定量关系,证明了各从链节直流电压控制算法可以独立运行,仿真结果验证了该定量关系的正确性。一台三H-桥七电平链式STATCOM的实验结果验证了分布式控制方案的有效性。

This paper presents a dc capacitor voltage distributed control system（DCS） for cascaded H-Bridge（CHB） multilevel static synchronous compensators（STATCOM）.The master cell dc voltage is controlled by central controller,and the slave cell dc voltages are controlled by individual cell controllers.Only one dc voltage needs to be sent to the central controller,and the signals received by all cell are same.This makes the communication system very simple.Meanwhile,when the cell number changes,the central control algorithm is almost unchangeable.But the sum of all dc voltage control variables is not zero,and this will degrade the performance of DCS.Under the master cell control,the quantitative relation between dc voltage control variable and power loss difference is deduced,and decoupling between different cells is verified.The correctness of this quantitative relation is showed by simulation,and the validity of DCS is verified by the experimental results.