Research on Modular Multilevel Converter Suitable for Direct-drive Wind Power System

This paper studies Modular Multilevel Converter (MMC) which is applied to Direct-drive wind power system. With the actual situation of wind power generation system, there is a control method presented. It is appropriate for an arbitrary number of voltage levels and the frequency of the AC side waving in a larger changing range. The method of determining the capacitance parameters in submodules is also designed. The converter model is built in PSCAD/EMTDC simulation platform; the simulation results validate the rightness and feasibility of the control method.