Power Loss Comparison of Different Matrix Converter Commutation Strategies

In this paper it is shown, how the power losses of a matrix converter using different commutation strategies can be determined by experimental methods and by simulation models. A comparison of the obtained power losses is presented as the main research result. Basis of this study is a laboratory prototype of a matrix converter, which uses a so-called switchable free-wheeling circuit for load current commutation and for protection purposes. During commutation sequences proceed in the 3x3-matrix the inductive load current is taken over by the free-wheeling circuit without load current interruptions and thus no dangerous overvoltage can occur. A high precision power analyzer is used to gauge the conduction and switching losses of the laboratory prototype. The measurement results are compared to the power losses calculated by a simulated four step commutation strategy. The applied four-step commutation is a commutation procedure, which gets by without additional protection hardware, i.e. the 3x3-matrix does not need to be extended for normal operation. The analysis considers the power losses and the converters efficiency depending on the switching frequency of the space vector modulation.