Wave-power unit and plant for the production of electric power and a method of generating electric power

• US 20050121915A1
• Filed: 12/19/2002
• Published: 06/09/2005
• Est. Priority Date: 01/08/2002
• Status: Active Grant

• Current Assignee: Seabased AB
• Original Assignee: Seabased AB
• Inventors: Leijon, Mats, Bernhoff, Hans
• Granted Patent: US 7,045,912 B2
• Time in Patent Office: Days
• US Class Current: 290/42
• CPC Class Codes: F03B 13/1885 and the wom is tied to the rem
• CPC Class Codes: Y02E 10/30 Energy from the sea, e.g. using wave energy or salinity gradient

Abstract

A wave-power unit has a floating body and a rotating electric generator mechanically connected to the floating body. A mechanical movement transmitter is arranged for transmission of vertical movements of the floating body to rotary movements of the generator rotor. A wave-power plant employs a plurality of wave-power units. Use of the wave-power unit and a method of generating electric energy as described.

Claims

1. A wave-power unit for the production of electric power comprising a floating body and rotating electric generator mechanically connected to the floating body, wherein a mechanical movement transmitting means is arranged for transmission of vertical movements of the floating body to rotary movements of the generator rotor, the rotor being connected to a turning body, which turning body is connected to the movement transmitting means, and the movement transmitting means is secured by its upper end to the floating body and by its lower end to the turning body and at least the lower part of the movement transmitting means includes a component that can be rolled up.

2. A wave-power unit as claimed in claim 1 wherein at least the stator of the generator is enclosed in a housing anchored in the sea/lake bed.

3. A wave-power unit as claimed in claim 2, wherein the rotor is also enclosed in the housing.

4. A wave-power unit as claimed in claim 1, wherein the rotor is situated on the outside of the stator.

5. A wave-power unit as claimed in claim 1, wherein the turning body is arranged outside the housing.

6. A wave-power unit as claimed in claim 1, comprising a first gear mechanism effecting a gear change between the movements of the turning body and the rotor.

7. A wave-power unit as claimed in claim 1, wherein the turning body and the rotor are arranged on a common, substantially horizontal shaft.

8. A wave-power unit as claimed in claim 1, wherein the turning body has circular cross section and in that the diameter of the rotor is larger than the turning body.

9. A wave-power unit as claimed in claim 4, wherein the movement transmitting means is secured by its upper end to the floating body and by its lower end to the rotor and in that at least the lower part of the movement transmitting means consists of a component that can be rolled up.

10. A wave-power unit as claimed in claim 1, wherein it is provided with spring means arranged to exert a torsional force on the rotor.

11. A wave-power unit as claimed in claim 10, wherein the spring rate of the spring means is adjustable.

12. A wave-power unit as claimed in claim 1, wherein the housing comprises a base plate, which base plate is arranged to rest on the bed of the sea/lake.

13. A wave-power unit as claimed in claim 1, wherein the length of the movement transmitting means is adjustable.

14. A wave-power unit as claimed in claim 1, wherein the housing is filled with a liquid.

15. A wave-power unit as claimed in claim 1, wherein the housing is primarily made of concrete.

16. A wave-power unit as claimed in claim 1, wherein the floating body is connected to a plurality of generators.

17. A wave-power unit as claimed in claim 1, wherein the stator winding is connected to a rectifier, which rectifier is preferably arranged close to the generator below the surface of the water, preferably inside the housing.

18. A wave-power unit as claimed in claim 1, wherein the generator is arranged to produce a voltage of varying frequency.

19. A wave-power unit as claimed in claim 1, wherein the movement transmitting means comprises a second gear mechanism to effect a gear ratio of the vertical movement of the floating body.

20. A wave-power unit as claimed in claim 1, wherein it comprises a free wheel arranged to convert oscillating rotary movement to unidirectional rotary movement.

21. A wave-power unit as claimed in claim 1, wherein the stator winding consists of a cable comprising a current conductor, a first semi-conducting layer surrounding the conductor, an insulating layer of solid insulation surrounding the first semi-conducting layer, and a second semi-conducting layer surrounding the insulating layer.

22. A wave-power plant comprising a plurality of wave-power units as claimed in claim 1, wherein the stator winding of each wave-power unit is connected via a rectifier to an inverter which is common to a plurality of wave-power units, which inverter is arranged to supply energy to an electric supply network.

23. A wave-power plant as claimed in claim 22, wherein at least one electric switchgear station is connected to the wave-power unit, which switchgear station comprises a watertight container housing switchgear components, which container is anchored in the sea bed.

24. A wave-power plant as claimed in claim 23, wherein a plurality of switchgear stations are connected to the wave-power unit, each switchgear station being connected to a number of wave-power units.

25. A wave-power plant as claimed in claim 23, wherein each switchgear station is connected to a receiving station arranged on land.

26. A wave-power plant as claimed in claim 23, wherein at least one of the switchgear stations comprises a step-up transformer and/or an intermediate station comprising a step-up transformer.

27. A wave-power plant as claimed in claim 23, wherein at least one of the switchgear stations and/or the intermediate station comprises a converter.

28. A wave-power plant as claimed in claim 23, wherein at least one of the switchgear stations and/or the intermediate station comprises means for storing energy.

29. A wave-power plant as claimed in claim 27, wherein at least one of the switchgear stations and/or the intermediate station comprises filtering means for filtering outgoing and/or incoming current and voltage.

30. A wave-power plant as claimed claim 23, wherein at least one of the switchgear stations and/or the intermediate station is filled with non-corrosive, buffered liquid.

31. A wave-power plant as claimed in any one of claims claim 22, wherein a filter and/or a transformer is/are arranged after the inverter.

32. A wave-power plant as claimed in claim 22, wherein the inverter, filter and/or transformer is/are arranged on land.

33. A wave-power plant as claimed in claim 22, wherein each wave-power unit is connected to the inverter via a cable arranged on or close to the sea or lake bed.

34. (canceled)

35. A method of generating electric power by mechanically connecting a floating body to a rotating electric generator, wherein the mechanical movement transmitting means is arranged to transmit vertical movements of the floating body to rotary movements of the generator rotor, the rotor is connected to a turning body, connected to the movement transmitting means, said movement transmitting means being secured by its upper end to the floating body and by its lower end to the turning body, and at least the lower part of the movement transmitting means consist of a component that can be rolled up.

36. A method as claimed in claim 35, wherein the method is utilized while making use of a wave-power unit.

37. A method as claimed in claim 36, wherein the spring means with adjustable spring rate is applied to exert a torsional force on the rotor and in that the spring means is adjusted so that resonance is obtained with the movement of the floating body that is estimated to occur for most of the time.

38. A method as claimed in claim 35, wherein the energy generated is conducted to a switchgear station, the components of which are arranged in a watertight container, which container is anchored in the sea bed.

39. A method as claimed in claim 38, wherein the switchgear station is connected to a receiving station arranged on land.

40. A method as claimed in claim 39, wherein a plurality of switchgear stations are connected to a common intermediate station, which intermediate station is connected to the receiving station.

41. A method as claimed in claim 38, wherein at least one of the switchgear stations and/or the receiving station is/are arranged below the surface of the water, preferably close to the sea bed.

42. A method as claimed in claim 38, wherein voltage generated is step-up transformed in at least one of the switchgear stations and/or the intermediate station.

43. A method as claimed in claim 38, wherein the outgoing voltage from at least one of the switchgear stations and/or from the intermediate station is alternating voltage.