Coupled Thermal / Electrical Analysis of High Powered Electrical Systems

This paper describes an approach based on coupled electrical, thermal and CFD analysis to predict the thermal performance of bussed electrical centers and junction blocks. Typically from 200 to 400 amps flow trough various circuitries, which lead to a significant amount of Joule heat dissipation that is responsible for the majority of heat loss in the system. The Joule heat dissipation distribution is not known prior to the solution and must be evaluated by simultaneously solving the electrical field. This can be accomplished through a "coupled electrical, thermal solution" scheme, where the voltage field is solved throughout the region using the electrical loads and boundary conditions (in addition to thermal and flow fields) during each iteration. The most recent temperature field is used to update the electrical resistivity of the conductors in the model. The power dissipation is then calculated and updated for all conductor elements. In this paper, a thermal/electrical/CFD model of a typical bussed electrical center (BEC) consisting of several relays, diodes and switches is discussed. The procedure for coupling the electrical and thermal effects is presented using 3D views of various circuitries. A discussion relating to the application of electrical boundary conditions (voltage and current BC\´s) is presented, followed by a detailed discussion of flow, thermal and voltage fields