OPTIMAL-CONTROL OF 3-LEVEL PWM INVERTERS

The harmonic loss-minimized optimal PWM strategy for three-level inver ters is investigated. The different PWM methods for low-, middle-, and high-speed regions are presented. It is shown that for three-level in verters the optimized strategy in all speed regions differs from the o ptimal PWM strategy of two-level inverters, The developed optimal cont rol ensures a minimum of motor harmonic losses for a predetermined num ber of commutations of three-level PWM inverters and for a given value of the fundamental harmonic voltage.