Temperature Dependent Reverse Recovery Characterization of SiC MOSFETs Body Diode forSwitching Loss Estimation In a Half-Bridge

In a hard switched MOSFET based converter, turn-on energy losses is predominant in the total switching loss. At higher junction temperature the turn-on energy loss further increases due to the reverse recovery effect of the complementary MOSFETs body diode in a half-bridge configuration. Estimation of the switching loss under different operating conditions at an early design stage is essential for optimising the thermal design. Analytical switching loss models available in literature are generally used for estimating the switching losses, due to its accuracy and simplicity. In this paper, the inaccuracy in the reported loss models due to non inclusion of temperature dependent reverse recovery characteristics of body diode, is investigated. A structured method to determine the temperature-dependent switching loss of a SiC MOSFET in a half-bridge is presented. A simple methodology has been proposed to analyze the carrier lifetime's temperature dependencies of a SiC MOSFETs body diode. Device parameters from a 1.2kV/36A SiC MOSFETs datasheet are used for developing the loss model and experimental validation of the model.