A new multilevel PWM method: a theoretical analysis

摘要

Generalization of the pulsewidth modulation (PWM) subharmonic method to control single-phase or three-phase multilevel voltage source inverters (VSI) is considered. An analytical expression of the spectral components of the output waveforms covering all the operating conditions is derived. The analysis is based on an extension of Bennet's method. The improvements in harmonic spectrum are pointed out, and several examples are presented, which prove the validity of the multilevel modulation.