Design and testing of silicon carbide JFETs based inverter

This paper presents the design and testing of a high frequency, high efficiency inverter using silicon carbide (SiC) JFETs power module. A rugged negative voltage gate drive circuit is used to solve the normally on problem of JFETs devices and avoid the bridge shot-through during power on or power off. The circuit can provide over-voltage protection, over current protection and over temperature protection circuits to ensure the safe operation of the SiC JFETs module and the integration of inverter system. SiC JFETs pspice model is established and discussed that the drive resistor voltage drop of SiC JFETs due to dv/dt is more severe than Si IGBT device compared the parameters of SiC JFET and Si IGBT at the same rated level. The simulation and measurement results show that SiC JFETs have short turn-on and turn-off times, which will result in lower switching losses than silicon (Si) IGBTs. The low on-resistance in SiC JFETs will result in lower conduction losses. The experiment results of a 1kW SiC JFETs based inverter showed at least 3% efficiency improvement by a SiC JFETs based inverter over a Si IGBT- based inverter.