Abstract-Despite transverse flux machines (TFMs) being intrinsically three-dimensional, it is still possible to model them analytically using relatively simple models. This paper aims to provide an insight into the behaviour of TFMs using a compact equation, which relates torque to the electric and magnetic loadings of the machine and a flux factor. The flux factor is also used to estimate the flux linkage and therefore the power factor of this kind of machines. It is shown that the low power factor of TFMs is not only due to leakage but also due to the nature of the electromagnetic interaction that takes place. The TFM developed at the University of Southampton is used as the basis of a case study to illustrate the trade-off between torque density and power factor, and to provide some design guidelines. The analytical results are verified using finite elements analysis and experimental data.

Abstract-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.

An analytical technique for the calculation of torque produced by a transverse flux machine is developed in this paper. In this technique, the magnets are replaced by their equivalent current sheets and the torque is calculated using the Lorentz force equation. The flux density distribution is calculated using a conformal mapping method that takes into account curvature and slotting. The result is a relatively simple equation that relates torque to the electric and magnetic loadings of the machine and a flux factor that depends on key machine geometrical parameters. The results of the analytical model are verified using finite element analysis and experimental data.

Abstract-Despite transverse flux machines (TFMs) being intrinsically three-dimensional, it is still possible to model them analytically using relatively simple models. This paper aims to provide an insight into the behaviour of TFMs using a compact equation, which relates torque to the electric and magnetic loadings of the machine and a flux factor. The flux factor is also used to estimate the flux linkage and therefore the power factor of this kind of machines. It is shown that the low power factor of TFMs is not only due to leakage but also due to the nature of the electromagnetic interaction that takes place. The TFM developed at the University of Southampton is used as the basis of a case study to illustrate the trade-off between torque density and power factor, and to provide some design guidelines. The analytical results are verified using finite elements analysis and experimental data.

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