DEVICE FOR A WINCH-OPERATED WAVE-ENERGY-ABSORBING BUOY

摘要

The invention relates to a wave-power plant where a floating buoy (23) arranges for energy absorption from the ocean waves. The buoy is anchored by a wire (14), which is reeled in on a self-tightening winch (12). When the wave motion(s) lifts the buoy, the winch cable drum is forced to rotate outwards. This rotating power motion is directed into a mechanical energy conversion subsystem and a hydraulic subsystem (20, 21) where the energy is converted by mechanic and hydraulic means and then stored in a hydraulic accumulator (8), from which a smooth flow of power may produced by a hydraulic power-take-off motor (10) coupled to an electric generator (28). The hydraulic means for converting the rotational energy also incorporate the mechanism that spools in the winch and keeps it tight, by using some of the stored energy in the accumulator to wind in the winch using a pump / motor as an agent for forcing the winch to rotate inwards, when the wave forces that previously forced it to rotate outwards fall off. The hydraulic subsystem may also provide overload protection of the plant by means of a pressure-limiting valve (6), limiting the maximum pressure of critical components. The mechanical energy conversion subsystem (20) may furthermore involve a slip clutch (16) between the winch cable drum and the hydraulic subsystem, which protects the power plant and the components in it against extreme loading during incidents of violent waves. The slip clutch determines the amount of energy per time unit that can be absorbed from a given wave, by slipping if too heavy torque or too high speed is attempted transmitted through it. Thereby, the wire is pulled out without offering increased resistance, and the buoy simply drifts with the wave until the wave has passed, with the result that the excess energy is left in the wave.