Three-phase current-source type soft-switched PWM rectifier for high-power applications and its design considerations

In this paper, a novel prototype of a three-phase current-source soft-switching PWM rectifier with new auxiliary resonant commutated circuits is proposed which can operate under zero current soft-switching principle. This rectifier is composed of six bridge-type main power switches with a reverse blocking diode and their related six auxiliary resonant commutation circuits including a switched type resonant capacitor in parallel with each main power circuit switch and two resonant inductors. The current flowing into the main power bridge circuit is transferred into an auxiliary resonant circuit and main power circuit switch is turned-off and on based on a principle of zero current soft-switching commutation. This new topology reduces switching losses without requiring complex energy recovery circuits. The proposed rectifier, operating at zero current switching transition, can be efficiently operated with a conventional hard switching PWM rectifier. In this paper, the steady-state operation mode of the current-fed ZCS-PWM rectifier is described for high-power applications, and analyzed for a design consideration. The effectiveness of this new active PWM rectifier is proved on the basis of some illustrative results obtained from computer simulation analysis.