Power Analysis in an SMC-Based Aerospace Transverse Flux Generator for Different Load and Speed Conditions

Transverse flux machines (TFMs) with independent phases are suitable for aerospace applications, where fault tolerance is required. Their complex 3-D flux path can be accommodated by using soft magnetic composites (SMCs). However, core loss evaluation of SMC-based electrical machines is limited by the accuracy of calculation models, most of which have been applied under no-load conditions. Therefore, the aim of this article is to compare experimental power and losses in an SMC-based TFM with results given by the equivalent circuit (EC) and the finite-element method, thus providing a better insight of loss mechanisms. At 5000 r/min, results show a good agreement; however, at 400 r/min, the experimental power on the load is lower than expected for high power values. Further measurements and analysis indicate that great iron losses are affecting power production at low speeds. Therefore, choosing a high-resistivity SMC material for the stator cores, with a good performance regarding high-speed losses, may entail some uncertainties for low-speed operation due to the magnetic behavior of SMC under load conditions.