A synchronous rectification featured soft-switching inverter using CoolMOS

For high voltage high power inverter applications, power MOSFET has not been widely used due to its slow body diode reverse recovery and high on-state voltage drop. This paper explores coupled magnetic type soft-switching technique to solve the body diode "hard" turn-off problem and uses the low on resistance CoolMOS to give low on-state voltage drop as well as synchronous rectification behaviour for reverse on-state period to achieve high efficiency power conversion. Detailed design consideration and optimization are discussed. A 2.5-kW CoolMOS based soft-switching inverter prototype is designed, fabricated and tested. Test results verified the above features.