Evaluation of Inverter Topologies and Switching Frequencies Regarding Harmonic Losses in PMSM

Electrification of propulsion systems is an opportunity that can enable aviation to become more sustainable. Since the propulsion system is a major part of aircraft, there is significant interest to optimize its weight while still meeting the safety requirements. Among different batteries, converters and inverters, a previous study has included different permanent-magnet synchronous machine designs based on their behavior if fed with an ideal sinusoidal current for an exemplary flight mission of a regional aircraft. However, in the propulsion system, the electric machine is fed by an inverter and thus additional voltage harmonics occur that lead to additional losses in the electric machine. This study therefore investigates the additional harmonic losses in three different machine designs presented in a prior study and determines whether the harmonic losses in these permanent-magnet synchronous machines have a significant impact on the overall losses of the propulsion system. Additionally, it is investigated if their consideration leads to different conclusions regarding the choice of inverter for the propulsion system in an optimization of overall propulsion system weight.