Packaging a 100kW All-GaN-based Three-level Active Neutral Point Clamped Power Module for Electric Vehicle Motor Drives

This paper, to the best knowledge of the authors, for the first time reports the packaging of a 100kW three-level active neutral point clamped (3L-ANPC) phase leg power module for electric vehicle (EV) traction inverter applications using 650V/150A e-mode gallium nitride high-electron-mobility transistors (GaN HEMTs). Compared with two-level (2L) half bridge power module, the main challenges of packaging a 3L-ANPC phase leg power module are high number of switches (6 switches vs 2 switches) and multiple commutation loops (1 commutation loop vs 4 commutation loops). In addition, there are four switches involved in the two long commutation loops. Those parasitic loop inductances must be minimized simultaneously. Those challenges are addressed by meticulous packaging of the power module, featuring low power loop inductances, double-sided cooled power module, low junction-to-coolant thermal resistance, symmetrical layout for the two parallel dies of each switch and mechanical robustness, etc. The simulated loop inductances are 1.92nH for the short loops and 5.21nH for the long loops, respectively; resulting in a 471V and 540V of turn-off voltage spikes in a double pulse test simulation at 400V/200A. The simulated junction-to-coolant thermal resistances are 0.37°C/W and 0.53°C/W for different switches, respectively.

I. Introduction

For next generation EVs, the power ratings of traction motors are increasing from tens of kW to hundreds of kW and the voltages of battery packs are also increasing from 400V to 800V, which call for EV traction inverters with a rated power of 100kW or higher at a DC bus voltage of 800V [1], [2]. Meanwhile, the targeted power density of the EV traction inverter listed by U.S. DRIVE (Driving Research and Innovation for Vehicle efficiency and Energy sustainability) is increasing from 13.4 kW/L by 2020 to 33kW/L by 2025 [3], making GaN HEMT a promising candidate due to its fast switching speed and low switching loss that can result in smaller heatsinks and footprints, and smaller passives by switching at higher switching frequency [4].