Optimized Common-Mode Voltage Reduction PWM for Three-Phase Voltage-Source Inverters

Abstract

In this paper, two new optimized common-mode voltage reduction PWM (CMVRPWM) strategies based on solving the established constrained nonlinear programming models in the time domain are proposed and analyzed. The proposed current ripple losses-optimized CMVRPWM (CRLO-CMVRPWM) minimizes the mean-square values of the three-phase current ripples by calculating the optimized special solutions of the voltage–second balance equations under the designed switching sequences. CRLO-CMVRPWM can achieve better output waveform quality than the existing methods. The proposed switching losses-optimized CMVRPWM (SLO-CMVRPWM) online optimizes the bus-clamping styles according to the phase currents to minimize the switching losses under different load power factors. Compared to the near-state PWM with fixed bus-clamping styles, SLO-CMVRPWM can reduce more switching losses in broader range of the modulation index. Simulation and experimental results verify the superiority of the proposed strategies to the conventional ones.