Development of a High-Power 25 kW PFC Converter with High-Efficiency of 99.6%

This paper presents an approach to enhance the efficiency of PFC by directly mounting SiC Bare Die MOSFETs on direct copper bonding substrates. Eliminating the need for separate packages effectively reduces parasitic inductances, leading to reduced switching time of the MOSFETs. Moreover, the direct placement of chips on a copper plate enables efficient heat transfer to the ambient and contributes to the overall system's size reduction. The
$\text{SiC}$
MOSFET chips are connected to the PCB using aluminum bond wires. Prior to the PFC stage, an active rectifier utilizing four conventional SiC MOSFETs is employed. The energy lost during operation is accurately measured using the calorimetry method, enabling precise determination of efficiency. Experimental results demonstrate the significant reduction in switching and conduction losses and improved efficiency achieved by the proposed approach compared to conventional power electronic systems. This approach offers the potential to develop high-power systems with improved efficiency, resulting in reduced energy costs and passive cooling.