Abstract：As an inverter, an important character of the modular multilevel converter is the modular capacitor voltage and circulating current can be controlled. A single phase state equations of the system is deduced in this paper, and with the equations, the harmonic elements of the circulating current and the capacitor voltages is analyzed. Based on verifying the second harmonic circulating currents of the three phases distribute with negative sequence, the three phase state equations are transformed into the negative double fundamental frequency dq0 coordinate system. The equations in the d and q frame of axes indicate the characteristics of the harmonic circulating currents and the zero sequence equations indicate the characteristics of the DC components of the modular capacitor voltages and the circulating currents. So, a decoupled control strategy of the harmonic circulating currents and the DC circulating currents is proposed. In the dq coordinate system, the traditional strategy is modified to suppressing the harmonic circulating currents perfectly, and in the zero sequence coordinate system, the capacitor voltage and the DC circulating currents are controlled. In different coordinate systems, the controllers do not affect each other. The final simulation and experimental results indicate the mentioned conclusions.
陈耀军, 陈柏超, 袁佳歆, 田翠华. 模块化多电平逆变器电容电压及环流控制[J]. 电工技术学报, 2014, 29(10): 166-174.
Chen Yaojun, Chen Baichao, Yuan Jiaxin, Tian Cuihua. The Control of Capacitor Voltages and Circulating Currents of the Modular Multilevel Inverter. Transactions of China Electrotechnical Society, 2014, 29(10): 166-174.
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