To meet the energy requirement of electrical components in industrial power applications, plug-in electrical connectors with contact fins are used. With a contact resistance below 0,1 mΩ this connector type can deliver currents of 100 A and higher. For the selection of the suitable connector size with limited available space or cooling, the designer needs an understanding how the connector reacts to electrical currents, including continuous load and pulse overload conditions. As datasheets typically include no information about pulse overload conditions, we developed a method to establish a thermo-electrical model for calculating the hot-spot temperature in the connector. Based on a literature study, absolute maximum ratings for the internal hot-spot temperature are discussed. With Infrared (IR) thermal imaging measurements on the connector time-dependent temperature readings were gathered for current pulses up to 8000 A_(ms) and a pulse duration of 100 ms. Geometry and material information were determined to build a transient thermal-electric finite elements method (FEM) model. For some parameters like contact area and thermal contact resistance an inverse modelling technique was applied, comparing simulation results and measurements. Based on the model, hot-spot temperature and location could be identified. As the FEM model took several hours to be calculated, we derived a lumped thermal system model from the full model, representing the FEM model by a Foster network. The network is only able to calculate the hot-spot temperature, but with a calculation time of seconds.
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