Hybrid Thyristor and SiC FET Power Module for High-Efficiency AC Motor Control

This paper presents the latest power module design for a novel topology that combines thyristors and silicon carbide junction field-effect transistors, namely a "ThyFET" topology, to achieve high-efficiency solid-state control for industrial motors. The ThyFET topology is more cost-effective and inrush-tolerant than the pure transistor solution, and more efficient and controllable than the pure thyristor solution of solid-state motor contactors. The recent progress on ThyFET development includes the prototyping of a second-generation ThyFET power module. The characteristic features are kept from the previous version with a peak voltage of 1.2 kV, a peak inrush current of 1 kA, three-phase bidirectional AC conduction, and normally OFF voltage blocking functionalities. Improved from the first-generation ThyFET module, the new ThyFET design has a 37.5% reduction in footprint, a 97.9% reduction in leakage current, a more uniform balance of on-state resistances across three phases, and a minimal 0.5 °C temperature difference in the steady-state thermal performance between two versions. Both the finite-element simulations and experimental results are presented to demonstrate the performance of ThyFET power modules.