High Power GaN Module Using 3D-Printed Liquid Coolers for Hard-Switching at Megahertz

Abstract:
This work presents a power module for high frequency operation, designed to get the maximum performance out of Gallium-Nitride (GaN) devices. The use of metal 3D-printed liquid coolers, ceramic insulation and advanced Indium interface material leads to extremely low thermal resistance and low parasitic impact on switching performance. The presented module consists of four half-bridges, rated for 400 V and output currents of 15 A. The thermal interface achieves a resistance of 1.38 K/W from junction to coolant at a chip cooling area of 19 mm(exp2), while the ceramic insulation contributes 3 pF to the switch-node. The low parasitic design enables a peak switching speed of 186 V/ns during a hard switched turn-on and 30 V overshoot after soft commutation at full load current.