In this study, a new analytical model is provided to calculate the effect of the pole offset on the output parameters of brushless DC (BLDC) motor. The proposed model is based on the two-dimensional analysis model and the direct solution of Laplace and Cauchy-Poisson equations for the magnetic field in the air gap and the magnets area. In this model, radial and tangential components of the magnetisation vector are calculated. Effect of pole offset on the radial and tangential components of magnetisation vector is derived. It is shown that in the case of a motor with pole offset although the length of the magnet decreases at the edges of the pole, the effective air-gap length remains constant. This study proposed two coefficients to model the reduced thickness of the magnets at the edges of the poles. Therefore, the flux density is calculated in the air gap and motor magnets. Based on the proposed model, effect of pole offset on the cogging torque ripple and back-electromotive force is achieved. These results are compared with the results of finite element and experimental tests and accuracy of the model is presented.

In this study, a new flux‐switching permanent‐magnet (FSPM) motor with two rotors and toroidal coil are introduced. First, the proposed FSPM (PFSPM) motor structure and performance principles are presented. Then, the performance parameters of the PFSPM motor, including flux linkage, back‐electromotive force, air‐gap flux distribution, inductance, eddy current loss, cogging torque and the output electromagnetic torque are compared with a conventional FSPM motor based on finite‐element analysis. Then, the effect of the angle between the two‐rotor poles on the performance parameters of the PFSPM motor is indicated. Finally, the PFSPM motor model is manufactured and the results of the finite‐element test are compared with the results of the experimental test and the accuracy of the finite‐element model is confirmed.

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