Gate Driver Design and Continuous Operation of an Improved 1200V/200A FREEDM-Pair Half-Bridge Power Module

FREEDM-Pair is an innovative power semiconductor switch which reduces the loss and cost through the hybrid integration of a Si IGBT and a SiC MOSFET. During the turn-off of the FREEDM-Pair, the Si IGBT is turned off first under ZVS condition and after a carefully selected delay time, the SiC MOSFET is turn-off. In this way, the turn-off loss of the Si IGBT is significantly reduced due to the ZVS turn-off condition. During the delay time, the current will be carried by the SiC MOSFET only. During the turn-on, the SiC MOSFET and the IGBT can be turned on at the same time. Due to faster turn-on speed of the MOSFET, the IGBT is also turned on under the ZVS condition. FREEDM-Pair also has better conduction characteristics compared to the Si IGBT by the combined current conduction capability of the unipolar and bipolar devices. Therefore the FREEDM-Pair provides an ideal option to realize the tradeoff between the cost and performance, and can be applied to main stream applications which currently use IGBT. Previously, the 1200V/200A FREEDM-Pair with individual gate terminals for IGBT and MOSFET have been designed and published. In this paper, a three terminal 1200V/200A FREEDM-Pair is presented and analyzed for the first time. In the three terminal FREEDM-Pair, a passive delay circuit is designed and integrated into the power module, so only one gate driver signal is needed. The designed delay circuit will generate the desired delay gate signal for the MOSFET automatically. To verify the designed gate driver function and the FREEDM-Pair performance in continuous operation, a half-bridge (HB) power module consisting of two FREEDM-Pair switches is developed. The continuous operation of the 1200V/200A FREEDM-Pair in a buck converter topology is reported for the first time.