A switching strategy of dead-time elimination for pulse width modulation converters

Abstract

A novel switching strategy of dead-time elimination for pulse width modulation (PWM) converters is presented in this paper. The proposed strategy determines whether a controllable switch should be turned on or not is based on the latest switch record of its corresponding upper or lower controllable switch in the same phase leg and its anti-parallel diode conduction state. This method only detects the lower anti-parallel diode conduction state in each phase leg for H-bridge PWM converters. Two controllable switches in the same phase leg are not needed to switch one after another by using this switching strategy. Dead-time is not needed even at the instant of the current polarity change. Therefore, dead-time can be completely eliminated. This method significantly solves dead-time effects in conventional PWM voltage source converters. The principle of the proposed switching strategy is described in detail. Simple logic equations that represent the switching strategy are presented. Simulation and experiment results using an H-bridge converter for passive loads are given to confirm the validity of this new switching strategy.