Comparison of Core Loss Characteristics of Interior PM and Flux-Switching PM Machines for EV Applications

This paper presents a comparative analysis of core loss characteristics between two widely studied types of permanent magnet (PM) machines: interior permanent magnet (IPM) and flux-switching PM (FSPM) machines, designed for micro electric vehicle (EV) applications. The primary objective is to enhance the understanding of core losses influenced by complex flux density waveforms and dc bias fields. The study first compares and tests the most popular core loss calculation techniques, including Fourier analysis and hysteresis-based models, using finite element analysis (FEA) simulations for the two baseline PM machines. The results demonstrate that the hysteresis-based modeling approach more accurately accounts for minor loops and dc bias effects. Both experimental measurements and FEA simulations indicate that neglecting these factors can lead to significant underestimation of core losses, up to 55% in experiments and 177% in simulations. Additionally, the FSPMM exhibits larger core losses than the IPMSM under the tested partial load conditions, highlighting the importance of accurately predicting core losses in such machines.