Circuit-Based Electrothermal Simulation of Power Devices by an Ultrafast Nonlinear MOR Approach

Abstract

This paper presents an efficient circuit-based approach for the nonlinear dynamic electrothermal simulation of power devices and systems subject to radical self-heating. The strategy relies on the synthesis of a nonlinear compact thermal network extracted from a finite-element model by a novel model-order reduction method requiring a computational time orders of magnitude lower than conventional techniques. Unlike commonly employed approaches, the proposed network allows reconstructing the whole time evolution of the temperature field in all the points of the domain with high accuracy. Electrothermal simulations are enabled in a commercial SPICE-like simulator by coupling such a network with subcircuits that describe the electrical device behavior by accounting for the temperature dependence of the key physical parameters. As a case study, the dynamic electrothermal analysis of a packaged silicon carbide power MOSFET undergoing a short-circuit test is performed, showcasing the performance of the approach and highlighting the need of including the thermal nonlinearities to achieve reliable results.