Fast Calculation of Semiconductor Steady-State Junction Temperatures in Power Converters

Semiconductor junction temperature is a key factor determining reliability and energy efficiency of power electronic converters. It also contributes directly to thermal management requirements, which impacts both volumetric and gravimetric power densities of power converters. The thermal coupling displayed by multiple semiconductor devices placed on the same heat sink can cause difficulty in the calculation of the steady-state junction temperature of each component. This paper describes a novel method by which the average losses of each individual semiconductor are used to quickly solve for all devices’ steady-state junction temperatures. The technique employs an iterative approach which then in turn only necessitates a single, brief, time-based thermal simulation, thus bolstering execution speed. When compared to the results from PLECS simulation software, the proposed method can accurately determine the steady-state junction temperatures in only 15-20% of the time, and after including the single, short simulation, there is a 30% speed improvement at low switching frequencies.