Assignment of turn-on and turn-off power and energy losses in a GTO

The authors discuss the turn-on and turn-off losses in a gate turn-off (GTO) thyristor which must be properly accounted for because they can comprise upwards of 60% of the total losses. The authors attempt to discuss and clarify the definitions of power loss and energy per pulse for the turn-on and turn-off intervals. It is shown that prior work defining turn-on and turn-off power and energy losses does not adequately include all losses associated with the turn-on and turn-off events. Thus, it will be difficult to account for all those losses determining the heating effects of the GTO unless improvements are made. An example shows that the error can be substantial (8 to 15%). For this reason, improved definitions that have an underestimation of only 1 to 2% of the switching losses have been proposed. It was also found that the gate losses during the turn-off event must be accounted for and that improved measuring techniques and instrumentation are both necessary and possible