Waveform quality comparison of scalar PWM methods for Modular Multilevel Converters

Modular Multilevel Converter (M2C) is the preferential topology used for high power applications in the recent years. Its high quality of output waveforms and high efficiency make it a powerful alternative to conventional two level converters. This paper gives an output waveform quality comparison of scalar PWM methods, used for M2C switching. It is found that output voltage characteristics are highly dependent on the PWM method used. Therefore, selection of the switching method is an important design issue in M2C studies. Comparison is based on Matlab generated switching pulse patterns and the results are validated by Simplorer based computer simulations.