In the field of renewable energy, ocean wave energy is one of the least commercialised resources.udThis is mainly attributable to the harsh environment and the technical requirementsudof the environment. In recent years, a vast array of new technologies have been developedudfor this application. Of these, some have considered the oscillatory action of the ocean wavesudconducive to the use of linear generators in direct-drive actuators.udLinear generators may be classi ed into either tubular machines, which encapsulate theudmagnetic udux very well, or single- and double-sided udat machines. Double-sided udat layoutsudexhibit very high force capabilities because of the presence of a second air-gap.udA Double-Sided Tubular machine is proposed which exhibits the force density of a doublesidedududat machine combined with the superior udux e ciency of a tubular machine. Theudhypothesis of the present research is that this new layout will accentuate these bene tsudbeyond the potential of the double-sided udat linear machine layout.udThe machine's performance was quanti ed on the basis of its force capability, the mathematicsudof which are dealt with in detailed magnetic vector potential calculations. Simulationsudof two full-scale machine designs and a prototype machine were performed usingudFinite-Element Analysis. Fourier analysis was employed extensively to quantify the performanceudof the designs.udThe mathematical model developed through this work is fairly accurate. The calculatedudmachine performance deviates from the simulated and measured force capabilities by atudmost 1.54% for all cases which are presented.udA simulated comparison between the double-sided udat layout and the double-sided tubularudlayout indicates that the latter may have up to a 47% smaller volume than the formerudand use as little as a 83% of the permanent-magnet material as the former.udThe results are compelling in terms of the possible advantages of the layout. The machineuddeserves further investigation, mainly into the mechanical design and integration into audcomplete wave-energy converter system. Notably, the bearing system requires investigationudwith due cognisance given to the nature of the application. Consideration may also be givenudto the use of soft-magnetic composites to eliminate the obstacles that tapered laminationsudpose in the commercialisation of tubular machines.
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