This paper proposes a three-phase isolated buck matrix-type rectifier with active regenerative snubber for data center power application. The proposed converter realizes zero voltage switching operation in primary side FETs and single-stage power conversion with power factor correction function. An active regenerative snubber is used to reduce snubber power losses and severe overshoot voltage spikes in secondary side rectifier FETs, enabling use of low-voltage FETs, which reduces the conduction loss. A configuration of the proposed converter is clarified and theoretical discussions including the active regenerative snubber is analyzed. Operation of the proposed converter is demonstrated using a prototype rated for 8 kW, three-phase 400 Vrms AC input and 400 V DC output. Experimental results show that overshoot voltage spikes in secondary side rectifier FETs is reduced by around 30% comparison with a theoretical value, achieving a maximum power conversion efficiency of 97.7% and a rated power conversion efficiency of 97.6%.
.jpeg.jpg "Yuki Ishikura, PhD photo")