链式STATCOM电容电压不平衡现象研究:(一）仿真和试验

由于链式静止同步补偿器(STATCOM)直流电容器各自独立，如何使这些电容器上的电压保持一致，是装置安全可靠运行需要解决的关键问题。而电容电压不平衡机理的研究则是制定电压平衡控制策略的基础。文中通过数字仿真和物理模型试验进行相互比较，研究了各种因素对电容电压分配的影响，指出开关脉冲延时不同、混合型损耗差异以及并联型损耗差异是造成电容电压不平衡的主要原因。其研究结果对于建立链式STATCOM数学模型，从而定量分析电容电压的不平衡程度，进而制定合理的平衡控制策略具有重要意义．

RESEARCH ON THE VOLTAGE UNBALANCE OF DC CAPACITORS OF CASCADE STATCOM Part One Simulations and Experiments

Since DC capacitors of cascade STATCOM are separate, their voltage may not be exactly balanced during operation periods. However, the mechanism of this kind of voltage unbalance has not been explained clearly up to now. In this paper, several factors are considered and discussed including switching loss, parallel loss, and time delay of gate pulse, and while simulations and experiments show that the slight differences of these inverters' parameters are the main causes of voltage unbalance. The conclusion is very important in the succeeding analysis and research for modeling of cascade STATCOM and designing controller to balance the voltages.