Reduced switching random PWM technique for two-level inverters

Abstract

This paper proposes reduced switching random PWM (RPWM) techniques based on Space Vector PWM (SVPWM) technique for conventional two-level inverters. In the proposed RPWM techniques, the switching frequency is randomized within a band lower than the nominal switching frequency at and around the peaks of the three-phase output currents. For the rest of the fundamental cycle, the switching frequencies are randomly selected within a band higher than the nominal switching frequency. The proposed method is able to spread the narrowband harmonic clusters similar to the conventional RPWM techniques and additionally produce less inverter output current distortion than conventional spread spectrum techniques. The proposed technique has been analyzed and has been verified using experimental results.