Wave energy convertor

Patent metadata

Field	Value
Publication number	US-9847697-B2
Application number	US-201615334847-A
Country	US
Kind code	B2
Filing date	Oct 26, 2016
Priority date	Oct 15, 2013
Publication date	Dec 19, 2017
Grant date	Dec 19, 2017

Abstract

A device and method for generating electric energy/power from a wave motion. The device comprises an input branch connected to a movable element, a secondary branch connected to a main electric generator, a power split transmission comprising a first mechanical port connected to the input branch, and a second mechanical port connected to a secondary branch, and a third port being a mechanical or electrical control port. The device further comprises a variable speed auxiliary electrical machine connected to the control port for mechanically or electrically controlling power distribution in the power split transmission. The device further comprises a control unit adapted for controlling the variable speed auxiliary electrical machine in such a way as to realize a one-way rotation of the main electric generator.

First claim

The invention claimed is:

1. A device for generating electric energy from a wave motion, the device being connectable to a movable element configured for performing an oscillatory movement under the influence of the wave motion, the device comprising:
a main electric generator,
an input branch operatively connectable to the movable element, the movable element, when connected to the input branch, being configured for imposing an oscillatory movement on the input branch as a result of the wave motion, the oscillatory movement being a periodic movement having a period wherein during alternating moments in time positive and negative speeds are imposed to the input branch,
a secondary branch operatively connected to the main electric generator,
a power split transmission comprising at least three ports, the at least three ports comprising:
a first mechanical port connected to the input branch,
a second mechanical port connected to the secondary branch, and
a third port being a control port,
the power split transmission being configured for distributing power between the at least three ports,
wherein the device furthermore comprises a variable speed auxiliary electrical machine operatively connected to the control port for controlling power distribution in the power split transmission, and
the device furthermore comprises a control unit configured for controlling the variable speed auxiliary electrical machine, in such a way as to realize a one-way rotation of the main electric generator during the whole period of the oscillatory movement.

2. A device according to claim 1 , wherein the control unit is configured for controlling power distribution of a positive power flow from the moveable element to the device in one part of a period of the oscillatory movement and of a negative power flow from the moveable element to the device in another part of the period of the oscillatory movement, during operation.

3. A device according to claim 2 , wherein said control unit is configured for performing said power distribution to and from any of the at least three ports of the power split transmission so as to shift the moments in time of imposing positive and negative speeds at the input branch with respect to the moments in time when positive or negative power flow from the movable element to the device occurs.

4. A device according to claim 1 , wherein the control unit is configured for realising a predetermined torque of the movable element so as to generate the maximum amount of energy during the period of the oscillatory movement.

5. A device according to claim 1 , wherein the power split transmission comprises at least one planetary gear box comprising a sun gear, a ring gear and a planet gear.

6. A device according to claim 1 , wherein the power split transmission comprises at least one differential unit.

7. A device according to claim 1 , wherein the secondary branch comprises at least a mechanical energy storage device adapted for storing at some moments in time mechanical power and for providing at certain moments in time mechanical power.

8. A device according to claim 7 , wherein the mechanical energy storage device is a flywheel.

9. A device according to claim 1 ,
wherein the at least three ports of the power split transmission consist of one input port, one output port and one control port, and
wherein the control unit is configured for extracting power from the movable element during movement of this element in only one direction.

10. A device according to claim 1 , wherein the at least three ports of the power split transmission comprise at least one input port, at least one output port and at least two control ports, and
wherein the control unit is configured for controlling the variable speed auxiliary electrical machine for extracting power from the movable element during movement of this element in a substantially upward direction and also during movement of this element in a substantially downward direction.

11. A device according to claim 1 , wherein the first mechanical port of the power split transmission is mechanically connected to the input branch of the device; and
wherein the second mechanical port of the power split transmission is mechanically connected to the secondary branch of the device, and the secondary branch is mechanically connected to the main electric generator; and
wherein the third port is a mechanical control port; and
wherein the device furthermore comprises a third branch that mechanically connects the third port of the power split transmission to the variable speed auxiliary electrical machine.

12. A device according to claim 11 , wherein said control unit is configured for controlling an auxiliary torque or an auxiliary acceleration or an auxiliary speed of the auxiliary electrical machine for controlling power distribution to and from any of the at least three ports of the power split transmission.

13. A device according to claim 1 , comprising an electrical variable transmission comprising said power split transmission and said main electric generator and said variable speed auxiliary electrical machine;
the electrical variable transmission having an inner rotor and an outer rotor and a stator arranged concentrically and being electromagnetically coupled, this electromagnetic coupling realising the main electric generator and said variable speed auxiliary electrical machine; and
wherein the inner rotor is mechanically connected to the input branch of the device and the outer rotor is mechanically connected to the secondary branch of the device, or vice versa; and
wherein the control port of the electrical variable transmission is an electrical port, and wherein the control unit is electrically connected to the variable speed auxiliary electrical machine comprised in the electrical variable transmission for controlling the power distribution in said electrical variable transmission.

14. A device according to claim 13 , wherein the device comprises at least one electrical energizing unit.

15. A device according to claim 14 , wherein the at least one electrical energizing unit comprises at least one electrical invertor unit.

16. A device according to claim 13 , furthermore comprising an electrical battery for temporal storage and retrieval of electrical energy.

17. A system comprising:
a device according to claim 1 , and
the movable element of claim 1 , connected to the input branch of the device, and optionally further comprising a gearbox operatively connected between the movable element and the input branch.

18. A method for generating electric energy from a wave motion using a device comprising an input branch connected to a movable element configured for performing an oscillatory movement under the influence of the wave motion; and a secondary branch operatively connected to a main electric generator; and a power split transmission comprising at least three ports including a first mechanical port connected to the input branch, a second mechanical port connected to the secondary branch, and a third port being a control port; and a variable speed auxiliary electrical machine operatively connected to the control port of the power split transmission;
the method comprising:
the movable element imposing an oscillatory movement on the input branch as a result of the wave motion, the oscillatory movement being a periodic movement having a period wherein during alternating moments in time positive and negative speeds are imposed to the input branch;
controlling a power distribution in said power split tr

Assignees

• Univ Gent

Inventors

• Degrieck Joris
• Van Paepegem Wim

Classifications

• H02K7/1853 Primary

  driven by intermittent forces · CPC title

• H02K11/30

  Structural association with control circuits or drive circuits · CPC title

• H02K7/06

  Means for converting reciprocating motion into rotary motion or vice versa · CPC title

• F05B2220/706

  an electrical generator · CPC title

• H02K99/10

  Generators · CPC title