• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.11
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• pp.1541-1543
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• 2013

This paper presents a spherical motor which can control in multi-degree of freedom operation. The spherical motor has been researched by many types of structure. Thhis paper shows a spherical shaped airgap and surfaced permanent magnets. Especially, The motor consists of dual rotor cores. Unlike a cylindrical motor, the spherical motor design can be considered with azimuth direction on spherical coordinates. Therefore the permanent magnet surfaced on the rotor need to be designed optimally in order to generate a sinusoidal magnetic flux density in the airgap. This paper presents results of optimal design for reducing torque ripple of the multi-degree of freedom spherical motor.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.25 no.6
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• pp.42-48
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• 2011

Generally, the structure without the stator core Axial Field Permanent Magnet (AFPM) generator was simple and there was nearly no cogging toque. And because it had the wide driving rate area, it had been being mainly used in the small wind power generation system. However, AFPM generator with non-slotted stator can't generate high voltage at low wind speed due to long air-gap. It is the reason of output efficiency drop. Therefore, in this paper, the AFPM synchronous generator with internal rotor and dual slotted stators for the small wind turbine is studied, and deal with a cogging torque minimization through the determination of optimum pole-arc ratio.