Optimal control of three-level PWM inverters

An harmonic loss-minimized optimal PWM strategy for three-level inverters is investigated. The different PWM methods for low-, middle-, and high-speed regions are presented. It is shown that, for three-level inverters, the optimized strategy in all speed regions differs from the optimal PWM strategy of two-level inverters. The developed optimal control ensures a minimum of harmonic losses for a predetermined number of commutations of three-level PWM inverters and for a given value of the fundamental harmonic voltage.