GaN Module Design Recommendations Based on the Analysis of a Commercial 3-Phase GaN Module

In this paper, a detailed analysis of a commercial 3-phase, 100 V, 270 A (per phase) GaN module is presented. A high frequency parasitic circuit model was derived for the module, which was simulated to demonstrate a unique sensitivity of low voltage GaN modules: its susceptibility to VDS overshoot at hard turn-off switching transients due to large currents, fast GaN switching, large package parasitics, and low VDS overshoot margins of 100 V rated dies. Hardware double pulse test (DPT) results confirmed this when the commercial module experienced premature failure due to VDS overshoot when hard switched at 36% of its current rating. Module design layout recommendations are provided based on an analysis of the commercial GaN module's layout (using 3D electromagnetic software) as well as GaN module layouts from existing literature. The paper concludes with hardware DPT results of a custom 100 V, 360 A GaN module. The hardware was successfully hard switched at 375 A, demonstrating the feasibility of low voltage (≤ 100 V), high current (> 300 A) GaN modules capable of hard switching at their die current ratings.