Abstract：In a cascaded power system, the system stability can be affected by the impedance interaction of the source converter and the load converter. Many literatures analyzed the effects on the impedance characteristics of the converter from different control methods and circuit parameters. Besides, different passive damping methods and control methods to improve the impedance characteristics of the converter are proposed to ensure the cascaded system stable. On the basis of the small signal model, an active damping method to emulate a virtual resistor, which is connected in parallel with the output of the converter’s small signal model, is presented in this paper. By this means, the output impedance of the converter can be decreased and the damping characteristics can be improved. The AC component of the output voltage needs to be sampled by the active damping controller so the steady-state operating point is not affected. Therefore, the effects caused by the impedance interaction between the source converter and load converter can be weakened. The effectiveness of this method is verified by the simulation and experiment results.
贾鹏宇, 李艳, 郑琼林. 电压型级联系统中减小源变换器输出阻抗的有源阻尼控制方法[J]. 电工技术学报, 2015, 30(8): 71-82.
Jia Pengyu, Li Yan, Trillion Q Zheng. An Active Damping Method to Reduce Output Impedance of Converters in Voltage Source Cascaded System. Transactions of China Electrotechnical Society, 2015, 30(8): 71-82.
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2015, Vol. 30 
