High efficiency soft-switching 3-phase PWM rectifier

A new soft switching 3-phase PWM rectifier with simple circuit configuration and high efficiency has been developed. The proposed circuit is a kind of auxiliary resonant commutated pole (ARCP) converter. The conventional ARCP converter requires 3 auxiliary reactors and 6 auxiliary switches for the soft switching auxiliary circuit and for these switching elements, a gate drive circuit and a control circuit are required, resulting in high part count as a disadvantage. In the main circuit proposed in this paper, the auxiliary soft switching circuit is composed of 2 auxiliary reactors, 2 auxiliary switches and several diodes. In addition, common use of the PWM control circuit for 2 switches will make the control circuit of the auxiliary switches simple. By means of function of the soft switching auxiliary circuit, the main switching element performs zero voltage switching operation and the auxiliary switches performs the zero current switching. In this paper, the circuit configuration and the operational analysis of the proposed circuit are described at first and then experimental results are reported. By using a prototype with 5 kW capacity, a conversion efficiency of maximum 98.8% and a power factor of 99% or higher were obtained.