This final paper deals with the calculation of losses in a three-phase converter based on catalog data of commercial IGBT modules. The losses were determined using the MATLAB Simulink software package. The chapters describe power electronics converters, as well as the algorithm for calculating losses, which is based on hysteresis pulse-width modulation. Through simulations in the MATLAB Simulink software package, IGBT module losses were tested for different amounts of phase current, DC voltage and switching frequency. The simulation results are presented in graphical diagrams and all results are commented on.