Design, Implementation, and Evaluation of a GaN-based Four-Leg Inverter with Minimal Common Mode Voltage Generation

Due to the introduction of wide bandgap (WBG) devices such as silicon carbide and gallium nitride devices, the power inverters with ultra-low loss, high temperature, and compact size are made possible for various applications. However, the increased dv/dt and switching frequency of WBG devices also aggravate the common-mode (CM) voltage related issues of the PWM inverter based systems. In the past few years, the magnified CM EMI emission and ground leakage currents in WBG based inverter systems are starting to draw attentions and becoming a concern among researchers and engineers. In this paper, the four-leg topology is investigated as a potential solution to the CM voltage generation of WBG inverters. Detailed design and implantation considerations of a GaN-based four-leg inverter are presented, and the performance of the inverter is also evaluated.