Model based temperature control system to increase the expected lifetime of IGBT power modules executed on a neutral point diode clamped three level inverter

The model based temperature control system examined in this paper increases the expected lifetime of IGBT power modules by decreasing the magnitude of temperature swings occurring during operation. In order to achieve this goal additional power losses are produced during low load conditions. This is carried out by presetting a reactive current. The three level neutral point diode clamped three phase inverter drives a permanent magnet synchronous machine. The basic functionality is demonstrated on a simple test cycle. In order to illustrate the beneficial usage on a more complex load cycle a driving cycle is exercised representing the electric vehicle as field of application. The improvement in regard to the expected lifetime and the generated additional power losses of the inverter and of the permanent synchronous machine will be addressed and discussed.