Design of a Low Leakage Pulse Transformer for Gate Driving of Multiple SiC MOSFETs for Induction Heating Applications

Parallel connected SiC MOSFETs are preferred as a single switch for near continuous-duty converter operation. The gate voltage is highly asymmetrical for these devices, and due to the small gate threshold voltage, they are sensitive to ringing in gate signals. This work proposes a novel low-leakage pulse transformer for a magnetically coupled Gate Drive Circuit (GDC) to feed the gate voltage to multiple isolated devices. The proposed pulse transformer can avoid spurious turn-on. The leakage- and self-inductances of the proposed transformer are computed using Finite Element Method (FEM) simulations. The calculated inductances are in agreement with the measured values. The performance of the magnetically coupled GDC with the proposed pulse transformer is experimentally verified by driving two parallel connected SiC MOSFETs for a high-speed offline induction cap sealing controller.