Modeling and measurements of loss components for different switching schemes in a three phase converter using CoolMOS transistors

This paper presents simulation and measurement loss determination results for different switching schemes in a frequency converter using CoolMOS transistors. Different Space Vector Modulation (SVM) schemes has been investigated. The simulation and measurement results show a close correlation. The losses in the MOSFETs have been determined with temperature measurement resulting in high accuracy. It has further been shown that the measured loss component in the MOSFETs can be divided into the switch loss and the conducive loss component using two different approaches. By measuring the on-state voltage drop as a function of current and temperature the conductive loss component can be determined. Furthermore, the switch loss component can be determined by measuring the switching transition of the component and calculating the switching losses as a function of the current. The second method, measures the loss component in the MOSFETs for a constant motor operation but with different switching frequencies. The obtained results of the conductive losses show an approximate error of 5%. Finally, the overall efficiency of a 4 kW Induction motor drive system were determined showing an approximate increase in efficiency of 1% using a discontinuous SVM.