A new approach to predicting reliability indices based on the numerical analysis of nonuniform temperature fields of power semiconductor devices (PSDs) is presented. Thermal analysis of the power diode module is carried out in a two-dimensional formulation with junction temperature Tjunc = 125°C. The finite difference method is used to solve the differential equation of heat conduction. During the numerical experiments, the ambient temperature (from 25 to 45°C) and dimensional orientation of the diode module vary. It was found that the temperature difference is more than 100°C. To analyze the reliability indices of the diode module, two mathematical models, Arrhenius and multiplicative (statistical), are selected. 1t is found that raising the ambient temperature from 25 to 45°C approximately halves the reliability indices of the power diode module. The vertical orientation of the module reduces the heat transfer and causes an increase in the failure rate indices to 10% under natural convection for Tamb = 25°C. When the diode module is lowered, the reliability indices drop by 18%, all other things being equal. The largest differences in the estimates of the reliability of PSDs are observed at a lower location of the diode assembly. For example, the failure rate for the Arrhenius model was 325 times higher than that of the multiplicative model for an ambient environment of 45°C. The necessity of taking into account the real unsteady temperature fields to increase the prediction reliability resource of PSDs is shown.
ASJC Scopus subject areas
- Electrical and Electronic Engineering