Nonlinear Analytical Model of a Double-Stator Flux Reversal Halbach Array Permanent Magnet Machine

For the application of an electrified propulsion system, this article proposes a double-stator flux reversal Halbach array permanent magnet (DS-FRHAPM) machine as one of the attractive propulsion machines, to obtain the features of high torque and low ripple. Meanwhile, a new exact hybrid analytical model, which combines the sub-domain method, the magnetic equivalent circuit (MEC) method, and the magnetic saturation coefficient, is proposed in this article. In the proposed analytical model, the sub-domain method is applied to obtain the inner and outer airgap flux density distribution, and the saturation effect is considered by a model combining the MEC with the saturation factor. In order not to change the interface conditions of the sub-domain solution and to relieve the computational burden, the magnetic potential distribution obtained by MEC is transformed into the surface current in the inner stator slot, which can be calculated scalarly with the armature current. Based on the fact of a relatively simple magnetic circuit flowing through the rotor, to further relieve the computational burden, a saturation factor is adopted to consider the saturation effect of the rotor core instead of MEC. Finally, the accuracy of the proposed analytical results is validated by the finite element method and experiment to assess its validity in the desired machine.