Electro-thermal modeling of power IGBT modules by heat pipe systems

This paper presents an electro-thermal model of an IGBT with its cooling system. A thermal model based on a Cauer Resistor-Capacitance (RC) thermal network, is developed in order to predict the IGBT junction temperature in transient operation. The thermal resistances and capacitances are obtained by a mathematical transformation that is applied to a model based on the Foster thermal network. An electrical model of the IGBT is also developed, and it takes into account the dependency of the static electrical parameters of the IGBT with the junction temperature. The electro-thermal model is considered in a boost converter applications, and two cooling modes are studied. The first one uses air convection technique, and the second one consists of a heat pipe cooling system of which the heat sink is cooled by cold plates using water circulation. The model predictions show the effectiveness of the heat pipe cooling system for different operating conditions such as the commutation frequency and the duty ratio. It is demonstrated that the heat pipe cooling system limits the junction temperature to low values which remain below the maximum admissible ones.