AN IMPROVED PSPICE MODEL FOR SIMULATION AND ANALYSIS OF THYRISTOR COMMUTATION CIRCUITS IN DC CHOPPERS

An accurate model of a thyristor in dc chopper commutation circuits is described using the available elements in the PSpice program library, The improved model, which takes into account the reverse recovery tim e during turn off, is used to simulate voltage and current commutated dc choppers. Simulation results, which include a study of commutation failure, agree with theoretical and experimental results. The model de veloped is useful for computer aided analysis and design of dc thyrist or choppers including the commutation circuits.