Selecting the coil core powder material for the output filter of a voltage source inverter

A comparative evaluation of the different, very popular powder magnetic materials for a voltage source inverter output filter coil core is presented. The basic continuous model of the inverter is simply based on the output filter transfer function. This model is used in the majority of inverter control designs. That is why the change of inductance and the increase of the equivalent serial resistance that is caused by power losses in the core and any other parasitic parameters of the coil should be known in the operating point because they depend on the frequency and the amplitude of the magnetising current. The theoretical calculation of these parameters variability is very inaccurate because of the complex voltage waveform on the coil, so the direct measurements of the inverter control transfer function are presented in aim to enable the choice of the most useful magnetic material for the inverter design.