Optimization of the Short-Circuit Behaviour of NPT-IGBT by the Gate Drive

SummaryShort-circuit withstand capability is an important feature for IGBT in inverter applications. With NPT-IGBT, the stress for the device is especially high if the short-circuit occurs while the device is carrying current (short-circuit type II). In this case, a high current peak and a large ovenvoltage can occur. In this paper, a model for the dependence of the current and voltage stress of a NPT-IGBT is given. It shows that the voltage stress is especially high for IGBT with a high rated current. A new Rate drive concept, the di/dt controlled gate clamping, that reduces the current and the overvoltage is investigated on. This gate drive concept is combined with a concept for turn-off of the steady-state short-circuit. Experimental results show that safe operation in every short-circuit situation is possible.