Mathematical model of gate-turn-off thyristor for use in circuit simulations

Owing to the lack of a detailed mathematical model for the gate-turn-off (GTO) thyristor, accurate simulation of power-electronic circuits involving GTO thyristors has not been feasible. The paper describes the theoretical development of an accurate analytical model of the GTO thyristor and the practical implementation of the model in industry-recognised circuit simulators. The GTO model is based on a network representation of the device structure. The derivation of the equations has been aided by known theoretical work, observations of experimental data and finite-element analyses of internal device behaviour. This development approach has enabled characteristics unique to power devices to be accounted for, including the effects of conductivity modulation and dynamic charge storage in the mid-region. The model has been implemented in SPICE simulators and the Saber simulator. Comparison of simulation results and experimental data verifies that the model has a high degree of accuracy over a wide range of operating conditions. A practical application of the GTO model in the design of the inverter is also given