Modelling a single phase, voltage controlled rectifier using Laplace transforms

The development of a 20 kHz, AC power system by NASA for large space projects has spurred a need to develop models for the equipment which will be used on these single phase systems. To date, models for the AC source (i.e., inverters) have been developed. A method is developed to model the single phase voltage controlled rectifiers which will be attached to the AC power grid as an interface for connected loads. A modified version of EPRI´s HARMFLO program is used as the shell for these models. The results obtained from the model developed are quite adequate for the analysis of problems such as voltage resonance. The unique technique presented uses the Laplace transforms to determine the harmonic content of the load current of the rectifier rather than a curve fitting technique. Laplace transforms yield the coefficients of the differential equations which model the line current to the rectifier directly