Lifetime as a control variable in power electronic systems

This paper presents a novel control strategy, on the example of a three-phase voltage source inverter, to increase the life-time of power semiconductor devices. Based on an online estimation of the junction temperatures the switching frequency is modified through the control to decrease thermal cycles. In addition the neutral point potential can be shifted using a flat-top method, resulting in an additional reduction of thermal cycles. So using the presented control system in-stead of an ordinary pulse width modulation the lifetime of power semiconductor devices is increased significantly.