链式静止无功发生器直流侧电压稳定性分析

摘要

链式静止无功发生器(SVG)直流侧电容电压存在二倍频波动，电压检测时常采用滤波电路对直流侧电压信号进行调理。文中重点研究了滤波环节对链式 SVG直流侧电容电压稳定性的影响。根据能量平衡的思想对链式SVG直流侧电压控制进行了建模，建立包含滤波环节的系统闭环模型，并进行稳定性分析，得到调节器积分时间常数大于滤波环节时间常数是系统稳定的必要条件。搭建了13电平SVG样机，在220 V和3 kV电压下分别进行了并网实验，实验结果验证了文中稳定性分析的正确性。%There exists 100 Hz ripple in the DC side capacitor voltage of the cascaded static var generator(SVG),and the filter circuit is often used in the detection of DC side voltage.Mainly the effect of the filter circuit on the stability of the DC side voltage is studied.The DC side voltage closed-loop control model containing the filter circuit is established according to the principle of the energy balance.An analysis of the stability of the control model shows that the necessary condition for the robust stability of the system is to obtain the regulator integral time constant greater than the filter time constant.A 1 3-level SVG experimental prototype is built.Experimental results under 220 V and 3 000 V voltage respectively have verified the correctness of the stability analysis.