Inverter design for hybrid electrical vehicles considering mission profiles

Due to the increased electrification of automobiles, the use of inverters in automobiles has increased also. Therefore, an exact layout of the used components based on the individual application is required. Because temperature is one of the critical parameters for system reliability, especially in power electronic applications, it is important to know the components temperature for every load condition respectively throughout entire mission profiles. This paper deals with the development of an advanced simulation program which is capable of computing the component temperature even for long mission profiles within an adequate amount of time and with satisfying accuracy. As an example, the losses in the semiconductors and in the dc-link capacitors of a simple three-phase bridge are determined. The necessary simplifications and their impacts on the results are explained in detail. After the losses are determined, they are fed into a flexible 3-dimensional lumped parameter thermal model. The accuracy of the thermal model can be scaled by selecting the number of elements. The thermal model is generated automatically after the material and geometric data are inserted. Here a convection cooler is modeled. This thermal model also calculates the heating of the coolant within the heat sink.