Comparative assessment of thermal processes in frequency converters

The topologies of voltage source inverters implicated now and in future for the needs of induction and traction frequency converters are considered. The two-level and three-level clamped diodes voltage source inverters are shown to be an optimal choice due to a number of reasons. The equations for numerical and analytical approaches of power losses evaluation are analyzed. The power losses evaluation of the chosen two- and three-level inverters is carried out. The thermal equivalent circuits of the single semiconductor device and power module on its basis for the two inverter topologies are presented. The temperatures of transistors and diodes in the steady state are determined. The boundary values of the switching frequency delivering equalities of the power losses and maximum temperatures of two- and three-level inverters' semiconductor devices are extracted.