Multiphysics Characterization of a Novel SiC Power Module

Abstract

This paper proposes a novel power module concept specially designed for highly reliable silicon carbide (SiC) power devices for medium- and high-power applications. The concept consists of two clamped structures: 1) a press-pack power stage accommodating SiC power switch dies and 2) perpendicularly clamped press-pack heatsinks, in which the heatsinks are in contact with electrically insulated case plates of the power stage. The concept enables bondless package with symmetric double-sided cooling of the dies and allows for an order of magnitude higher clamping force on the heatsinks than what can be applied on the dies. The concept has been evaluated in a first demonstrator (half-bridge configuration with 10 paralleled SiC dies in each position). The experimental methodologies, setups, and procedures have been presented. The commutation loop inductance is approximately 9 nH at 78 kHz. The junction-to-case thermal resistance is approximately 0.028 K/W. Furthermore, a simplified 3-D finite-element thermomechanical model representing the center unit of the demonstrator has been established for the purpose of future optimization. The accuracy of the simulated temperatures is within 4% compared to the measurements. Finally, a 3-D thermomechanical stress distribution map has been obtained for the simplified model of the demonstrator.