A New Method for Simulating Power Semiconductor Circuits

This paper deals with the digital computer simulation of electric circuits containing power semiconductors (diodes and thyristors). The semiconductors are supposed to operate with line commutation. After surveying briefly the traditional simulating methods, a new general method is introduced: ``the method of adjusted voltage sources.´´ Using this method, the semiconductors are represented by voltage sources. In the case of a conducting semiconductor, the voltage of the voltage sources corresponding to the semiconductors is zero, but, in the opposite case, it is adjusted to cause zero current through the semiconductor. This means that the simulation is performed similarly as in the case of linear circuits, but in every point of the simulation, several auxiliary computations are to be carried out in order to obtain the voltage of the nonconducting semiconductors. The operation of the program using this method was verified by numerous examples, including the computation of switching transients and quasi-stationary state. It must be noted that the program cannot be used for finding the quasistationary state. However, the method can be extended easily for simulating, e.g., short-circuit phenomena. Examples show the efficiency of the new simulation method.