Design and rating comparisons of PWM voltage source rectifiers and active power filters for AC drives with unity power factor

Given terminal constraints of unity power factor in ac drive applications, two ac drives are possible: one with a pulse-width modulation voltage source rectifier (PWM-VSR) and the other using a diode rectifier and an active power filter. Despite numerous publications for the two drives, the features and advantages between them have not been clearly explained. This paper presents a theoretical analysis and systematic comparison between the two drive topologies. Converter kVA ratings, dc-link voltage requirements, switch ratings, semiconductor losses, and reactive component designs are considered for the evaluations.