Two-dimensional power device simulator considering an integral external circuit equation

A two-dimensional power device simulator that takes into account an integral external circuit equation and Dirichlet (voltage) boundary condition is developed. This simulator has the features of achieving a fast and stable calculation even when the physical variables (p, n, φ) vary radically, just as does turnoff performance with an inductive load of power devices. The simulator is used to investigate the insulated gate bipolar transistor (IGBT) inductive turnoff phenomenon. Calculated waveforms agree qualitatively with the experimental results. This method can be expanded to deal with a more complicated branch circuit, such as a snubber. The principle of this method is that the integral equations for each constituent circuit are solved using Newton´s iteration method by satisfying Kirchhoff´s law at the point with which each circuit is connected