Accurate Power Loss Model of a Three-level ANPC Inverter Utilizing Hybrid Si/SiC Switching Devices

The use of hybrid Si/SiC switches is becoming an attractive solution to improve conversion efficiency and reduce cost of power converters. A very good efficiency-cost tradeoff can be achieved by using a high current rated Si IGBT in parallel with a low current rated SiC MOSFET for high frequency switches in combination with an appropriate gate control mechanism. However, the analytical power loss models developed for ANPC inverter topology using Si IGBT or SiC MOSFET devices will have low accuracy for hybrid Si/SiC switches. This is because the current and voltage profile of hybrid Si/SiC switches depends on the current ratio and gate control strategy between the two devices. A precise power loss model is essential for power converters to aid engineers choose the appropriate semiconductor device configuration and control strategy in terms of the tradeoff between cost and efficiency. This paper presents an accurate power loss model of an ANPC inverter employing hybrid Si/SiC switches that accounts the current and voltage profile and gate control strategy of the hybrid Si/SiC switches. The validity of the proposed power loss model is verified using measured experimental loss data.