Model based thermal evaluation of a modular power inverter system

Modular power inverter systems for auxiliary drives in utility vehicles can meet various different customer requirements. A model based approach can be used for validating the thermal design of those systems in any suitable modular configuration. This contribution is focused on an equivalent lumped thermal network model for a modular inverter system on a given heat sink concept. The proposed network representation is based on spatial splitting of the heat sink geometry whereby the lumped network elements are parametrized by means of the heat sink geometry. Since the proposed network is easy and straightforward, a minimum of variables are introduced to adjust the temperature results empirically with FEM results on certain reference operation points. Furthermore, modularity is considered due to the coolant and therefore, customer specific placement of modules can be investigated. Finally, the proposed model is compared with FEM results of a worst case system configuration, the influence of the introduced adjustment variables is shown and further validation results with thermal measurements and FEM results of different system configurations are given.