基于改进阶梯波调制的链式STATCOM直流电容电压平衡策略

摘要

研究采用阶梯波调制的链式STATCOM直流侧电容电压不平衡问题.介绍阶梯波调制法和电流间接控制的基本原理,分析导通角与电容电压变化关系.提出了基于改进阶梯波调制法的电容电压平衡策略,使电容电压大于平均电压的链节电压上升区间宽度减小,电容电压小于平均电压的链节电压上升区间的宽度增大,从而向平均电压逼近.基于5个链节仿真模型的仿真实验和基于12个链节实验装置的物理实验证明了该方法的可行性和有效性.%The imbalance problem of DC capacitor voltage existing in cascade STATCOM is studied by using ladder wave modulation method in this paper.The basic principles of ladder wave modulation method and current indirect con?trol are introduced,and the variation relationship between conduction angle and capacitor voltage is analyzed.On this basis,the ladder wave modulation method is modified,and a novel capacitor voltage balance strategy based on the mod?ified ladder wave modulation method is proposed,which makes the width of rising region of voltage chains with capaci?tor voltage higher than the mean value decrease,and that with capacitor voltage smaller than the mean value increase, so that all the chains'voltages will approach toward the mean value.A simulation experiment based on a 5-link simula?tion model and a physical experiment based on 12 link devices demonstrate the feasibility and effectiveness of the pro?posed method.