Abstract-The archimedes wave swing (AWS) is a system that converts ocean wave energy into electric energy. The goal of the research described in this paper is to identify the most suitable generator type for this application. Of the conventional generator types, the three-phase permanent-magnet synchronous generator with iron in both stator and translator is most suitable, because it is cheaper and more efficient than the induction generator, the switched reluctance generator, and the permanent-magnet (PM) generator with an air-gap winding. The paper also proposes a new transverse-flux PM (TFPM) generator topology that could be suitable for this application. This new double-sided moving-iron TFPM generator has flux concentrators, magnets, and conductors on the stator, while the translator only consists of iron.Index Terms-Direct-drive generator, linear machine, permanent-magnet (PM) machine, transverse flux machine, wave energy.
Permanent magnet motors with rare earth magnets are amongst the best candidates for high performance applications such as automotive. However, due to their cost and risks relating to security of supply, alternative solutions such as ferrite magnets have recently become popular. In this paper the two major design challenges of using ferrite magnets for a high torque density and high speed application, namely their low remanent flux density and low coercivity, are addressed. It is shown that a spoke type design utilizing a distributed winding may overcome the torque density challenge due to a simultaneous flux concentration and reluctance torque possibility. Furthermore, the demagnetization challenge can be overcome through careful optimization of the rotor structure, with the inclusion of non-magnetic voids on the top and bottom of the magnets. To meet the challenges of the high speed operation an extensive rotor structural analysis has been undertaken, during which electro-magnetics as well as manufacturing tolerances are taken into account. The electromagnetic studies are validated through testing of a prototype, custom built for static torque and demagnetization evaluation. The disclosed motor design surpasses the state of the art performance and cost, merging the theories into a multi-disciplinary product.
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