A 650 V, 2.1 mohm GaN Half-bridge Power Module for 400V EV Traction Inverter Application

Compared with silicon and silicon carbide vertical power devices, the lateral structure of gallium nitride (GaN) high electron mobility transistors (HEMT) has a very different packaging style with all electrodes on one side of the package. This makes it harder to realize high power GaN modules. This paper presents the design and development of a compact 650 V, 2.1 mohm GaN half-bridge power module. The overall dimension of the GaN power module is 64mm x 98mm x 4.7mm. 24 GaN devices are placed symmetrically on two sides of a printed circuit board (PCB) substrate, enabling liquid cooling from both sides. The PCB layout is designed to reduce the stray inductance of the power loop to 0.42 nH. The module demonstrates a small 18.5% voltage overshoot when working at 400V/200A, and the turn-on, turn-off energy at 400V, 300A are 6.8 mJ and 0.7 mJ, respectively. The tested junction to coolant thermal resistance is less than 100K/kW.