Abstract The capacitive voltage low-frequency ripple problem of modular multilevel converter (MMC) limits its application in low-frequency applications such as direct-drive permanent magnet wind power generation. To solve this problem, this paper proposed a topology and its control method of medium-voltage wind power generation system based on improved MMC. Compared with the traditional ripple suppression method based on "high-frequency common-mode voltage+high-frequency current injection", this method does not bring about common-mode voltage problems. Firstly, the overall structure of the system was described, the role and design principles of the high-frequency energy channel in the system were introduced, and then the working mechanism of suppressing the low-frequency ripple of the MMC capacitor voltage through the high-frequency current was analyzed in depth. Then the detailed control method of the system was introduced. Finally, a 5MW/10kV medium-voltage wind power generation system was established on the Matlab/Simulink platform for simulation research, and a 2kW experimental prototype was set up for experimental verification. The results prove the correctness and effectiveness of the proposed solution.
Guan Weide,Huang Shoudao,Huang Xiaoqing. A Medium-Voltage Wind Power Generation System Based on Improved Modular Multilevel Converter and Its Control Scheme[J]. Transactions of China Electrotechnical Society, 2018, 33(16): 3782-3791.
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2018, Vol. 33 
