Thermo-Electrical Modeling of Multilevel Switching-Cell-Array-Based Power Converters.

The switching-cell array is a flexible device formed by a matrix arrangement of highly optimized switching cells all at the same voltage rating. The switching cells within a switching-cell array can be interconnected in different ways, providing some degrees of freedom that could be exploited to pursue reduction and/or more even distribution of power losses in the power converters. To compare power converter legs based on different configurations of switching-cell arrays, a proper steady-state average thermo-electrical model is required, to estimate losses and temperature of all power semiconductor devices within the converter legs. This work presents the thermal analysis of power devices within power converter legs based on switching-cell arrays. Detailed transient and steadystate average thermo-electrical models are provided to calculate the conduction and switching losses, together with the junction temperature of the power devices. The steady-state average thermo-electrical model operates faster than the transient model, with comparable accuracy to the transient model. The accuracy of the steady-state average model is evaluated by comparison to the transient model, under different scenarios and through analytical studies. Finally, both thermo-electrical models are verified through experimental tests.