Discontinuous PWM-based common-mode voltage suppression method for three-phase inverter

Abstract

In high-voltage and high-power applications, continuous pulse-width modulation methods (CPWM) suffer from reduced inverter efficiency due to high switching frequency, and the common-mode voltage (CMV) generated can also cause electromagnetic interference and current harmonics. This paper proposes a discontinuous pulse-width modulation (DPWM)-based CMV suppression method to suppress CMV and reduce switching losses simultaneously. CMV values associated with various reference voltage vectors are analyzed first, and then CMV suppression conditions in different sectors are calculated. The proposed control strategy can correct the modulation wave of DPWM easily using a look-up table, which lists the suppression conditions calculated above to decrease the computation burden, thus suppressing CMV while simultaneously reducing switching losses. The strategy exhibits universality across various types of DPWM. Simulations and experiments confirmed its effectiveness.