Fast and Reliable DC/DC Converter Used in Protection Circuit for Normally On Devices Against Short-Circuit Condition

摘要

The use of normally on Silicon Carbide (SiC)JFET devices poses the question of safety and reliability inVoltage Fed Inverter (VFI) applications. Indeed, when the JFETis not driven with a sufficient negative voltage, the JFET isconducting and the VFI is short-circuited. Therefore, it is neededto generate a negative voltage to turn-off the JFET to protect theVFI. In this paper, an improved solution to protect the JFETand the system is proposed. Circuit description of an innovativetopology using a Forward-Flyback topology with Primary SideSensing (PSS) technique and Output Voltage Estimation basedon Time Constant Matching (OVETCM) is presented. Moreover,the converter protects the VFI for an input range from 3 V to610 V and up to 200 °C. Experimental results are provided andvalidate the design of the converter.