GB2412697A

GB2412697A - Wind turbine

Info

Publication number: GB2412697A
Application number: GB0407079A
Authority: GB
Inventors: Patrick Hugh Betts
Original assignee: PRIMERA CONSULTANCY AND DESIGN
Current assignee: PRIMERA CONSULTANCY AND DESIGN
Priority date: 2004-03-30
Filing date: 2004-03-30
Publication date: 2005-10-05
Also published as: GB0407079D0

Abstract

A wind turbine comprises a set of turbine blades 16 mounted for rotation at the top of a hollow column 10. The blades are arranged to power a generator 20 to generate electricity. The hollow space within the column 10 is used to store potential energy when the generator is not consuming all the power from the rotating blades, and the generator is adapted to be powered by the potential energy when the rotating blades are idle. The potential energy may be in the form of a raised weight, a tensioned spring or pumped water.

Description

24 1 2697 Wind Turbine This invention relates to a wind turbine for

generating electricity.

Wind turbines comprise a rotor with a set of turbine blades mounted on the top of a tower. When the turbine is used to generate electricity, a generator is also mounted at the top of the tower so as to be driven directly (possibly through a gear train) by the rotation of the rotor, such rotation being produced by wind impinging on the turbine blades, to turn them.

Wind turbines work effectively within a range of ambient wind speeds, but there are times when the wind is too light to turn the blades, or so strong that the blades The invention is therefore concerned with a way of storing excess wind energy which cannot be converted into electricity immediately by the generator, for use to drive the generator at a time when the blades cannot do so According to the invention, there is provided a wind turbine comprising a set of turbine blades mounted for rotation at the top of a hollow column, with the blades being arranged to power a generator to generate electricity, wherein the hollow space within the column is used to store potential energy when the generator is not consuming all the power from the rotating blades, and wherein the generator is adapted to be powered by the l potential energy when the rotating blades are idle.

Preferably the hollow column is enclosed with continuous walls.

Preferably potential energy is stored by lifting a weight suspended within the hollow column, and the potential energy is released by allowing the weight to fall.

However other methods of storing potential energy are also within the scope of the invention. For example, energy may be stored by rotating a flywheel, by pumping water into the hollow space within the tower or by tensioning a spring or springs.

In very strong winds, the rotor may be braked to prevent it overspending, and potential energy can be recovered from the braking process.

The invention makes use of the enclosed space within a wind turbine tower to store energy. As this space is enclosed, the energy storing mechanism is hidden and maintained safe from interference from outside.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a perspective view of a wind turbine; and Figure 2 shows a cross-section through a wind turbine according to the invention. - 3 -

Figure 1 shows a typical wind turbine which has a tower 10, a nacelle 12 mounted at the top of the tower and a rotor 14 with three turbine blades 16. The turbine is shown mounted on land, but similar structures can also be mounted off shore, with the bottom of the tower 10 on the sea bed. The nacelle 12 can rotate to face the wind direction.

Figure 2 shows the tower 10 and the nacelle 12 in cross section. The rotor 14 drives a shaft 18 which in turn drives a generator 20, such that when the rotor rotates, the generator generates electricity. This is conventional technology.

As can be seen in Figure 2, the tower 10 is a hollow tube.

The tube can be formed from metal, concrete or other materials. The function of the tower is to support the nacelle and the rotor with its blades sufficiently far above the ground so that the blades can rotate and so that the blades are exposed to an uninterrupted wind flow. The tower therefore needs to be high, and there will therefore be a significant amount of space within the tower.

At the top of the tower, a cable drum 22 is mounted with its axis across the drum. A weight 24 is suspended from a cable 26 wound on the drum. The drum can be driven from the rotor shaft and/or can drive the rotor shaft through a system of meshing gear wheels 28, which my be provided with appropriate clutches to enable the connection between the drum 22 and the rotor shaft 18 to be engaged or - 4 disengaged. A releasable ratchet mechanism can be used to allow the drum to be rotated in the winding up direction, but to prevent the drum rotating in the opposite direction until this is specifically called for.

An electric motor 30 is also provided to rotate the drum to lift the weight 24.

At times of high wind and little demand, surplus electricity generated by the generator is used to power the electric motor 30 to crank the weight up the column.

The motor is controlled by a computer that judges the electrical energy being generated compared with the wind force available.

In times of high demand and little wind, the computer releases the weight which in turn drives the generator shaft which in turn generates electricity.

At times of extremely high wind, the rotor shaft and drum can be coupled together so that the rotor itself directly rotates the drum to wind up the weight, thus having a braking effect on the rotor which may be desirable.

Computer control can be used to engage and disengage the rotor 14, the generator 20, the drum 22 and the motor 30, to make most efficient use of the wind energy and of the potential energy represented by the height of the weight 24 above the ground. The computer could also selectively release the weight as a power reserve to smooth out electricity generation in times of fluky winds.

When the weight is allowed to fall to drive the generator, the rotor 14 will be uncoupled from the generator so that the energy stored by the position of the weight does not have to rotate the rotor and blades.

As mentioned earlier, lifting a weight is only one of many ways of storing potential energy.

The principle of the invention is that wind turbines do not always experience ideal wind speeds for their operation. Sometimes the wind is too strong; other times it is too light and the invention allows energy to be stored at times of high wind and to be used to operate a generator, in place of the rotor and its blades, at times of light or no wind. - 6

Claims

Claims 1. A wind turbine comprising a set of turbine blades mounted for

rotation at the top of a hollow column, with the blades being arranged to power a generator to generate electricity, wherein the hollow space within the column is used to store potential energy when the generator is not consuming all the power from the rotating blades, and wherein a generator is adapted to be powered by the potential energy when the rotating blades are idle.
2. A wind turbine as claimed in Claim 1, wherein the hollow column is enclosed with continuous walls.
3. A wind turbine as claimed in Claim 1 or Claim 2, wherein potential energy is stored by lifting a weight suspended within the hollow column, and the potential energy is released by allowing the weight to fall.
4. A wind turbine as claimed in Claim 3, wherein the weight is suspended from a cable, and the cable is wound on a drum mounted at the top of the tower.
5. A wind turbine as claimed in Claim 4, wherein the drum is fixed on an axle, and means are provided to either engage the axle with the rotating blades, so that the drum is turned to wind up the cable and lift the weight, or to engage the axle with the generator, so that when the weight is released and the drum is rotated by the weight, rotation of the axle drives the generator. - 7
6. A wind turbine as claimed in Claim 5, wherein suitable clutches are provided between the axle, the rotating blades and the generator, and means are provided to sense the speed of rotation of the blades and the height of the weight in the tower, and to control the clutches in accordance with inputs from the sensing means to maximise the output from the generator.
7. A wind turbine as claimed in Claim 1 or Claim 2, wherein potential energy is stored by rotating a flywheel.
8. A wind turbine as claimed in Claim 1 or Claim 2, wherein potential energy is stored by pumping water into the hollow space within the tower.
9. A wind turbine as claimed in Claim 1 or Claim 2, wherein potential energy is stored by tensioning a spring or springs.
10. A wind turbine as claimed in any preceding claim, wherein the rotor may be braked to prevent it overspending in very strong winds, and potential energy can be recovered from the braking process.
11. A wind turbine as claimed in any preceding claim, wherein a clutch arrangement is provided to connect either the rotor, or the potential energy store, to the generator. - 8
12. A wind turbine as claimed in any preceding claim, wherein the generator powered by the blades is the same generator as the generator adapted to be powered by the potential energy.
13. A wind turbine substantially as herein described, with reference to any one embodiment shown in the accompanying drawings.