The concept of IGBT modelling and the evaluation of the PSPICE IGBT model

The ability to calculate power losses in the Insulated Gate Bipolar Transistors (IGBTs) embedded in a series resonant converter is of great interest at ALSTOM Power, Växjö. Correctly estimated power losses are valuable in various situations, e.g. when evaluating new types of IGBTs or different control strategies. Therefore, it is desirable to investigate and evaluate the existing computer based IGBT models, where the majority is implemented in various circuit simulators. In this thesis, the MicroSim PSPICE IGBT model is evaluated with respect to the application of the series resonant converter. Particularly, this involves the issues of conduction losses and switching losses both at hard and soft switching. To be able to characterise a specific IGBT, a major parameter extraction procedure is performed, adapted from Hefner [7]. The parameters are subsequently used in the simulations and the result is compared with reference values of the measured power losses in the series resonant converter. This procedure is carried out for three different IGBTs from different manufacturers (Eupec, Semikron and Toshiba). The evaluated model failed to comply with the stated specifications, mainly owing to the poor performance at soft switching with a capacitive snubber, and consequently, some possible future alternatives are given.