'Dead-band' PWM switching patterns

Abstract

It is pointed out that continuity has been assumed to be a necessary condition for the implementation of switching patterns for pulse-width-modulated (PWM) converters. This is probably based on the intuitive feeling that switching pattern discontinuities dead-band-degrade the quality of output/input voltage/current waveforms by introducing low-order harmonics. The authors challenge this notion by showing that discontinuous switching patterns for PWM converters can yield better performance than their continuous counterparts. Performance is defined as harmonic distortion normalized with respect to switching frequency, and serves as a measure of comparison with continuous PWM techniques. The applications considered include general-purpose and application-specific solid-state power supplies utilizing voltage current inverters and PWM synchronous or buck-type rectifiers. Theoretical considerations are verified on an experimental unit.<>