Enhanced Gate Driver Design for SiC-Based Generator Rectifier Unit for Airborne Applications

Abstract

Featuring higher breakdown voltage, faster switching frequency, lower ON-state resistance, and smaller size in comparison to traditional Silicon (Si) IGBTs, silicon carbide (SiC) MOSFETs have become an attractive solution for achieving high power density and efficiency in airborne applications. However, the move to higher voltages and their more compact packages challenge the insulation design. In particular, low-pressure working condition of the aircraft degrades gas dielectric strength, which leads to an increased risk of partial discharges. Thereby, this paper presents a comprehensive design of a gate driver for SiC-based Generator Rectifier Units (GRUs) for variable frequency airborne applications. A design method to control the peak electric field in high field strength regions was used to ensure the field strength in air and the PCB dielectric remain within an acceptable range. High bandwidth Rogowski switch-current sensor (RSCS) for short-circuit (SC) and over-current (OC) protection as well as phase current reconstruction are implemented to enhance the gate driver performance. Experiments were conducted, successfully verifying the gate driver’s performance meets all the design targets.