Accurate Analytical Modeling for Switching Energy of PiN Diodes Reverse Recovery

PiN diodes are known to significantly contribute to switching energy as a result of reverse-recovery charge during turn-off. At high switching rates, the overlap between the high peak reserve-recovery current and the high peak voltage overshoot contributes to significant switching energy. The peak reverse-recovery current depends on the temperature and switching rate, whereas the peak diode voltage overshoot depends additionally on the stray inductance. Furthermore, the slope of the diode turn-off current is constant at high insulated-gate bipolar transistor (IGBT) switching rates and varies for low IGBT switching rates. In this paper, an analytical model for calculating PiN diode switching energy at different switching rates and temperatures is presented and validated by ultrafast and standard recovery diodes with different current ratings. Measurements of current commutation in IGBT/PiN diode pairs have been made at different switching rates and temperatures and used to validate the model. It is shown here that there is an optimal switching rate to minimize switching energy. The model is able to correctly predict the switching rate and temperature dependence of the PiN diode switching energies for different devices.