Three-phase AC-DC unidirectional PWM multiple-switch rectifier topologies-selected properties and critical evaluation

This paper takes a critical look at existing unidirectional multiple-switch rectifier topologies with an aim of giving a comparative analysis and simple classification. Since power factor correction and harmonic distortion of the line currents remain issues of high priority in the field of power conversion and utilization, the rectifiers considered herein, some of which are derived from DC chopper circuits i.e. switch-mode power supplies, may fulfil these conditions without additional complex control systems. The chopper derived topologies have an additional advantage of cost effectiveness in comparison to naturally commutated line converters or six-switch bi-directional PWM converters. Included are converters with and without transformer coupling. Since the selection of a particular topology depends on various factors such as efficiency, cost effectiveness, simplicity, type of load or application, the desired power density etc., the paper aims at pointing out the essential considerations for a clear and accurate design, application and selection criteria. Simulation results of selected topologies are also presented. Where possible, solutions based on practical circuits have been quoted as an aid to resolving associated technological problems.