Modeling and experiment research on turn-off characteristics of pulsed power thyristor

Pulsed power thyristors have been widely used in pulsed power systems due to their controllability, large through-flow capacity and high repetition frequency. To study the device's electrical characteristics and the circuit transient process, based on research of reverse recovery process of pulse thyristor, a macro model of pulsed power thyristor applying to MATLAB/Simulink software platform was established in this paper. This model combined ideal thyristor model in MATLAB with reverse recovery current module, which was designed to describe the reverse recovery process of thyristor after the conducting current rapidly decreased to zero. In the model, reverse current increased with a constant di/dt when accumulated carriers rapidly decreased; and then when space charge region started to recover, the thyristor's recovery current curve was described by two hyperbolic secant curves with different time constant. This established model achieved the smooth transition of current curve from storage time to dropping time, and thus improving the precision of thyristor model comparing with the model provided by Simulink library. In addition, experiment was designed to verify the macro model. According to the experimental data, the reverse recovery voltage and recovery current curve calculated by the macro model fitted well with the experiment results.