Analysis of transverse flux machines using a virtual mutual inductance approach

In this paper a virtual mutual inductance approach is used to analyse the performance of transverse flux machines (TFMs). The virtual mutual inductance between the stator windings and the magnets' equivalent currents is obtained by integrating the flux produced by the stator windings over the surface of the magnets. Key design parameters such as back EMF, torque, phase inductance and power factor are readily calculated using the proposed methodology. This method is also used to optimise the geometry of a particular machine which provides an insight into the relationship between power factor and torque. Furthermore, the insights gained suggest a design approach that takes into account the power factor of TFMs, which may help unlock their potential through a trade-off between torque density and power factor. The results obtained using the analytical model are verified using 3D finite element analysis (FEA) and experimental data.