Junction Temperature Control Strategy for Lifetime Extension of Power Semiconductor Devices

The lifetime of power semiconductor devices mainly depends on their thermal stress. In particular, temperature swings cause damage due to different coefficients of thermal expansion of the different materials, which are used in power semiconductor devices. These temperature swings occur when the environmental temperature or the load conditions and with them the power losses change. Junction temperature controllers are able to extend the expected lifetime by reducing the occurring temperature swings. This paper proposes two control strategies to calculate a suitable set value for junction temperature controllers, which leads to a smoother temperature course with fewer swings. Both strategies do not affect the normal operation by for example limiting the output parameters. They affect the efficiency of the power electronic circuit to influence the power losses and thermal conditions.