刘追,刘振兴,李翠.(23期已送排）一种基于最近电平调制方式的MMC电压均衡改进方法[J].电测与仪表,2017,54(24):. Liu Zhui,Liu Zhenxing,Li Cui.An Improved Voltage Balancing Method Based on MMC Nearest Level modulation[J].Electrical Measurement & Instrumentation,2017,54(24):.
(23期已送排）一种基于最近电平调制方式的MMC电压均衡改进方法
An Improved Voltage Balancing Method Based on MMC Nearest Level modulation
Nearest level modulation is one of the main modulation strategies in the modular multilevel converter, which has obvious advantage in the converter with large number of voltage levels. To ensure the effect of voltage balancing, the capacitor voltages of submodules are usually required to be collected and sorted all the time, and a large number of voltage acquisition modules are needed to achieve this goal in practical engineering. In view of the above, this paper proposes a replacement method, using the integral amounts of bridge arm current to modules conduction time to sort , that indirectly realizes the effect of voltages sorting, and the method can effectively reduce the voltage sensors. Meanwhile, on the basis of the replacement method, This paper introduces the maximum voltage deviation among submodules, on the premise that the system output characteristics in allowable range, it can greatly reduce the frequency of IGBT switching caused by sorting. The model of MMC with 21 levels is realized by RT-LAB, the IGBT switching frequencies and submodule capacitance voltages under two voltage balancing methods are compared, the simulation results show that the proposed method is Feasible and effective.
