Switching losses and and operational frequency limitations of GTO thyristors in PWM inverters

The losses of GTO thyristors in pulse width-modulated (PWM) inverters are investigated on the basis of the theoretical switching waveforms. Snubber losses, derived from the dynamic device parameters, prove to increase overproportionately with the inverter power, and a novel low-loss snubber is presented. Other limitations on the operational frequency are demonstrated. Theoretically obtained switching losses of GTO thyristors with and without snubbers show good agreement with experimental test data.<>