Electro-thermo-mechanical modelling and analysis of the press pack diode in power electronics

Abstract

This paper details a finite element modelling approach of the press pack assembly process for a diode in a power electronic module. Molybdenum and aluminum graphite have been investigated as suitable materials for the contact pad. Contact analysis has been used to model the pressurized thermal interface in order to extract both the stress and temperature distribution in the diode. Average temperature and von Mises stress on the chip for a combination of clamping pressure, load current and contact pad material have been extracted from the modeling results. At present, based on the assumptions and modeling parameters used, Aluminum Graphite seems to have better performance in comparison with molybdenum in terms of generating a lower average chip temperature. Additionally optimum clamping pressure has been estimated by performing a numerical optimisation analysis in order to minimise both the average temperature and stress in the chip.

Power Device Losses in Two-Level Converters with Direct Current Controllers for Grid Connected Applications

“…The development of electrothermal models is an area of increasing interest in power electronics. This type of models enables the investigation of the loss distribution within the devices comprising a converter and the analysis of the resulting junction temperature excursion [12,20,21], as well as passive components [22]. As a result of the thermomechanical stresses, the power electronic components degrade, resulting in a reduced lifetime [23,24].…”

An initial consideration of silicon carbide devices in pressure-packages

“…Analytical models widely cited in the literature [10]- [12] were used to estimate the thermal and electrical contact resistances. A direct multi-physics coupling analysis involving electro-thermo-mechanical interactions which approximate the joule heating and the resulting thermally induced deformation and stresses on structure on the press-pack module was numerically simulated in the finite element software.…”