High-Current 800 V Ultra-Low Inductive Power Module with SiC MOSFETs on Insulated Metal Substrates

Abstract:
This paper presents the design of a high-current 800 V power module for a future 492 kVA traction inverter using five parallel packaged TO-263 SiC-MOSFETs on an insulated metal substrate (IMS) aimed at cost-effectiveness. The design achieves an ultra-low inductive commutation loop for enhanced switching performance and effective thermal management by utilizing the aluminum core as return path, shielding surface and heat-distributing baseplate. The best-in-class SiC semiconductor was selected using a Hard-Switching Figure of Merit (HSFOM). The power dissipation of SiC-MOSFETs is calculated using analytical formulas including synchronous rectification and blanking times. A single-phase halfbridge module has been constructed for evaluation purposes. First measurement results with phase currents up to 500 A show an excellent switching performance with a commutation loop inductance of 2.54 nH and a junction to heatsink thermal resistance of 1.18 K/W per device.