An increased awareness of the environment and the growing energy needs of countriesudlike China and India have accelerated the search for sustainable alternatives to fossiludfuel energy sources. Generating electricity from ocean waves is a viable alternative.udThis is because energy densities are sufficient to supplement the grid and thus makeudit economically viable. The seasonal supply profile also matches the demand profile.udThere are currently many different devices operating on different principles, the mostudpromising of these is the oscillating body device using a linear generator.udLinear generators are able to convert linear motion into electrical energy withoutudthe need for intermediate gears, screws or crank shafts. This increases the overalludefficiency and makes the device more reliable. Static force simulations were done onuda novel linear generator design. The generator combines the duel air-gap of a doubleudsided topology with the encapsulation of the magnetic field in a tubular topology.udThis results in an increased force density, but also large cogging forces. The coggingudforces consist of end-effects cogging forces that are caused by the interaction of theudPermanent Magnets (PMs) with the stator ends, as well as cogging forces which areuddue to the interaction of the PMs and stator slots. The topic of this thesis is to findudsuitable methods of reducing the cogging forces.udThe end-effect forces were reduced by changing the stator length and altering theudstator ends shape. Creating a quadratic b’ezier curve end shape and optimisingudthe stator length reduced the end-effect cogging force from 630 N to 7 N. The slotudcogging forces were reduced by dividing the PMs into two sections and to shift theudouter PMs by one slot pitch relative to the inner PMs. This resulted in a decreaseudfrom 663 N to 25 N. However, a compromise needs to be made between reducingudthe cogging forces and not reducing the machine performance. Increasing the statorudlength increases the machine volume and dividing the magnets reduces the thrustudforce. This needs to be taken into account when designing a new machine.
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