Electrothermal simulation methodology for power devices and integrated circuits

In this paper, an original method of electrothermal modeling of power electronics devices is proposed, the study being limited to a constant duty cycle operating chopper circuit. In order to overcome inherent problems in the implicit method and the "slowness" of the electric simulator, a supervisor software handles an interactive dialog between the thermal and the electrical simulators so as to minimize the working time of the latter. Thus, the electrical simulator is only used for computing the steady-state electric response of the circuit proposed and only specifically over a certain operating period so as to determine mean losses dissipated in the device at the temperatures imposed by the pseudo-computing step of the electrothermal simulator. This method takes advantage of the speed of the thermal simulator PYRTHERM developed for electrothermal simulation of power devices or circuits and originally solving the 3D heat diffusion equation by applying a Fast Fourier Transform algorithm. Indeed, this software allows for the computation in just a few minutes of transient 3D thermal responses for the particular structures of power ICs.