Applying Coupled Inductor to Voltage and Current Balanced Between Paralleled SiC MOSFETs for a Resonant Pulsed Power Converter

Paralleling the silicon carbide (SiC) MOSFETs is a cost-effective solution for increasing the pulse current rating. However, the device mismatch and asymmetrical circuit layout would lead to an imbalance voltage and current of the paralleled SiC MOSFETs. In this paper, a passive approach that an inversely coupled inductor was implemented for a resonant pulsed power converter. The coupled inductor enables even imbalanced voltage and current suppression of the parallel SiC MOSFETs, and also helps with the pulse width adjustment. The operating principle, analysis of the voltage and current balance mechanism, and the coupled inductor design are fully presented and discussed. Finally, a 200~300 VDC input, -8 kV output prototype was built to validate the analysis and effectiveness of the proposed concept.