Alternative Location

Following the preference for high speed and low forces to its limit would result in the electric machine being driven at the same amplitude as the hydrofoils. This would effectively bypass the influence of the pivot arm altogether and result in the linear generator being coupled between the hydrofoil and the foundations directly. An example design study can be used to find the ultimate position of a single linear generator coupling the pivot arm to the base. The maximum permitable active length is now dictated by the clearance between the pivot arm at its lowest position and the base, which varies according to the distance from the post. To provide the pivot arm with the same total moment from a single linear generator, the force which that generator is expected to react will clearly decline as distance from the post increases. Using the generator data as above, and dictating that the active length of the machine must be a whole number of three phase modules, it is possible to examine the relative features of generators placed at all points along the arm. The extremities of position are 0.5 m and 10 m from the post. The force required for this range is shown in Figure 7.8

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Figure 7.8: Force required to exert moment at different generator positions

If the minimum is taken as 2 metres from the post, the total force is kept well below 1 MN and the design study becomes more illuminating. Figure 7.9 shows some possible design criteria on which an appropriate generator could be chosen.

The smallest and lightest machine has an overall width of 0.6 m and a mass of 10 tonnes. If the linear generator were situated here it would follow the 12 m vertical oscillations of the hydroplanes, which pivot around the top of the post some 11 m away. The resulting motion is hence no longer linear but traces a circular arc. To account for this, the translator and stator of the generator could also be made to have the same curvature.

Figure 7.9: Design study of generator distance from post
Renewable Energy Eco Friendly

Renewable Energy Eco Friendly

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable.

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