3-phase PWM boost rectifier circuit topologies using 2-level and 3-level asymmetrical half-bridges

A 3-phase PWM boost rectifier is described that uses DC link inductors and an asymmetrical half bridge to obtain a unity fundamental power factor supply current with a low total harmonic distortion. The paper describes how the rectifier circuit structure can be broken down to form a fundamental circuit topology that contains two mutually decoupled boost power converter circuits. These boost circuits contain two near-triangular voltage sources, phase shifted from one another by 60° in the AC supply cycle, two DC link inductors and two semiconductor switches per circuit. The 3-phase bi-directional switches used in the bridge have very low electrical stresses with a low switching frequency, zero-voltage switching and a 0.2 p.u. current rating. Extensive analysis of the circuit switching states is presented and comparisons are made with 3-phase rectifiers using AC inductors. The operation of the rectifiers are illustrated with reference to simulation and experimental results