A generalized algorithm of space-vector PWM for a new type of modular multilevel converter

Due to adopting new type of multilevel structure, the modular multi-level converter (MMC) is really modularized in both topology and mechanical structure. A generalized algorithm of multilevel space vector pulse width modulation(PWM) is proposed for the new type of converter. Combining with the structural feature and operational principle of MMC, its space vector state is analyzed; taking reducing switching loss and distortion of output voltage waveform as object, the method to choose redundant voltage vectors, the optimal synthetic sequence of voltage vectors and the optimal allocation of action period of generalized zero-vector are determined; based on the PWM of two-level space vector, the transition matrix for action period between multilevel voltage vectors and two-level voltage vectors is derived. Simulation results under multilevel show that the proposed algorithm is correct and extensible.