A novel no-dead-time sinusoidal modulation method for three phase inverter

Abstract

A lthough the dead time in pulse-width modulation (PWM) inverters prevents short circuiting of the dc source, it also causes serious problems such as waveform distortion and voltage decreases. In this paper, a novel modulation method that combines the concepts of a six-step square wave and space vector modulation (SVM) is proposed. Compared with the conventional SVM methods in which the dead time should be set to avoid short circuiting problems, the proposed novel no-dead-time modulation method not only increases the switching frequency potential by enabling one transistor at a time in each phase leg without considering dead time setting but also reduces the switching loss with only three transistors operating in every section in one cycle of rotation. The PWM duty ratio formula of the specified section for each power transistor is derived and verified using software for power electronics simulation (PSIM). The simulation model of this novel modulation method is constructed and tested by using a three-phase inductance-resistance load. The simulation results are presented to confirm the validity of the proposed modulation method.