VGE,th(T) and VCE(T)-method to measure the cooling of an IGBT after short circuit in an inverter

摘要

In order to protect an inverter of a sudden failure due to aged semiconductors, it is necessary to monitor the state of health of those in the inverter application. To measure the state of health of the chip-solder, it is not necessary to heat up the whole device to the thermal equilibrium. It is sufficient to heat up the chip only, in this case. This can be done by driving a short circuit pulse with reduced gate voltage. By measuring the cooling behaviour and comparing it with the initial state it is possible to detect chip-solder degradation. Aiming to measure the cooling of IGBTs, two different methods are used, the VCE(T) and the VGE,th(T) method. These methods are presented in the following.