Performance evaluation of silicon-carbide MOSFET in three-phase high-power-factor rectifier

A high-voltage silicon-carbide (SiC) power MOSFET was evaluated on two high-power factor (HPF), three-phase resonant rectifiers; a non-isolated, 2-kW buck rectifier and an isolated, 3-kW two-switch forward rectifier. By replacing an IGBT switch with a SiC power MOSFET switch that has an equivalent current rating, the efficiency of both the non-isolated and isolated resonant rectifiers were significantly improved. The non-isolated buck rectifier using SiC MOSFET switches could deliver approximately 80%–40% more power than the rectifier using equivalent IGBT switches. Moreover, the efficiency of the isolated two-switch forward rectifier, which was operating with full load and switching frequency of 67 kHz, was improved by approximately 2% when IGBT switches were replaced by SiC power MOSFET switches. The IGBT loss was approximately 4.5% of the total output power. The loss of the SiC MOSFET was only 2.5% of the total output power under the same operating condition. When the prototype circuit was modified to operate at twice the switching frequency, the rectifier using SiC MOSFET switches could deliver approximately 60% more power than the rectifier using equivalent IGBT switches.