PWM strategy dedicated to the reduction of DC bus capacitor stress in embedded three phase inverter

This article proposes a new PWM strategy, called Unified Double Carrier PWM (Uni-DCPWM), which allows one to reduce DC link capacitor RMS current value of an embedded low voltage three phase voltage source inverter. Instead of using 2 adjacent active vectors and zero vectors to balance the reference vector in terms of volt-second at each switching period as in most of PWM strategies in the literature, this strategy uses 3 consecutive active vectors (at high voltage level) or 2 non-adjacent active vectors and a zero vector to reproduce the reference vector. Analytical calculations show that this strategy effectively reduces DC link capacitor RMS current value comparing to Space Vector PWM (SVPWM) for high power factor loads. However, RMS value of load current harmonics due to switching of this strategy is higher than SVPWM. This strategy is adapted to volume constrained environment such as automobile.