• The Transactions of the Korean Institute of Electrical Engineers B
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• v.53 no.4
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• pp.229-236
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• 2004

In this paper, the effect of permanent magnet overhang structure on the characteristics in Brushless DC motor has analyzed quantitatively. We classified the overhang structure as symmetric and asymmetric. 3D equivalent magnetic circuit network (EMCN) method which uses the permeance as the distributive variable is used for the efficient analysis of magnetic field. The overhang effect which increases the linkage flux at the stator is verified by comparison between overhang and no overhang structure. In addition, it is known that no load back electro motive force (EMF) is also increased due to the overhang effect. In case of asymmetric overhang structure, the ratio effect of the upper to lower overhang length on the magnetic forces is analyzed. Form the analysis results, the variation of the asymmetric overhang ratio has a significant effect on the axial magnetic force except the radial and tangential magnetic forces. The validity of the analysis results is also clarified by comparison between calculated results and measured ones such as back EMF and cogging torque.

• Journal of Magnetics
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• v.21 no.4
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• pp.577-585
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• 2016

In this paper, model of the axial-flux permanent magnet synchronous generator (AFPMSG) having arc-shaped trapezoidal permanent magnets (PM) is presented. The proposed model reduces the cogging torque and torque ripple, at the expense of lowering the average output torque. Optimization of the proposed model is performed by considering the asymmetric overhang configuration of the PMs, as to make the output torque of the proposed model competitive with the conventional model. The time stepped 3D finite element analysis (FEA) is performed for the comparative analysis. It is demonstrated that the torque ripple of the optimized model is highly reduced as well as average output torque is increased.