The purpose of this master thesis was to create a model of an IGBT in a single pulse test circuit and connect this model to a model of a Gate Unit. The IGBT model and the single pulse test circuit were both implemented in MATLAB and the Gate Unit was implemented in Simulink. The purpose of this model was to test the actions of the gate unit, so that the initial tuning could be done before going to the lab. Since no tests were performed in the lab, it was not possible to see how much of the testing that could have been done by simulations. However, the actions of the IGBT model much resembled the actions of the real component, even though some drawbacks were clear, such as the lack of tail current and tail voltage. These comparisons could be made between simulated characteristics and recordings from a previous test with the same component.