Circulating Current Suppressing Method Based on Active Damping Control of MMC Considering Low-Frequency Oscillation
Xu Qianming1, Luo An1, Ma Fujun1, Xiong Qiaopo1, Wang Lingzhi2
1. National Electric Power Conversion and Control Engineering Technology Research Center Hunan University Changsha 410082 China; 2. State Grid Hunan Electric Power Company Changsha 410000 China
Abstract：In order to analyze and suppress the low-frequency circulating currents of modular multilevel converter (MMC), a transient mathematical model for the sum of capacitor voltages and the circulating current of arm is established. The model reveals the principle of low-frequency oscillation under abnormal conditions. And then, the analytical expressions of oscillation frequency and the resonance point of 2nd circulating current without circulating current control are derived. In order to inhibit both low-frequency oscillation and 2nd circulating current, a circulating current suppressing method (CCSM) based on active damping control is proposed, which is simple without decoupling and coordinate transformation. Finally, the simulation and experimental results show that this method can suppress the low-frequency oscillation in transient state as well as 2nd and 2nd above circulating currents in steady state simultaneously.
徐千鸣, 罗安, 马伏军, 熊桥坡, 王凌志. 考虑低频振荡的MMC有源阻尼环流抑制方法[J]. 电工技术学报, 2015, 30(24): 118-126.
Xu Qianming, Luo An, Ma Fujun, Xiong Qiaopo, Wang Lingzhi. Circulating Current Suppressing Method Based on Active Damping Control of MMC Considering Low-Frequency Oscillation. Transactions of China Electrotechnical Society, 2015, 30(24): 118-126.
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2015, Vol. 30 
