GB2559110A

GB2559110A - A wind turbine

Info

Publication number: GB2559110A
Application number: GB1619730.3A
Authority: GB
Inventors: Roberts Mark
Original assignee: Individual
Current assignee: Individual
Priority date: 2016-11-22
Filing date: 2016-11-22
Publication date: 2018-08-01
Also published as: GB201619730D0

Abstract

A vertical axis wind turbine 1 comprising a support structure; a blade 3 connected to the support structure pivotable about the turbine axis, where the blade extends radially from the support structure such that the longitudinal axis of the blade is perpendicular to the turbine axis. Other aspects include: Slowing the rotation of a blade of a wind turbine by transferring excess electrical power provided by a generator 5 to an electromagnet of a braking system 21 to cause the polarity of the electromagnet to attract the polarity of a permanent magnets of the shaft to slow its movement. A method of mounting a turbine blade to a rotor by attaching the blade to the rotor in a first direction to provide a force directed towards the rotor using a first fixing means and further attaching the rotor to the blade in a second direction to provide a force directed towards the blade using a second fixing means. A method of operating a wind turbine, comprising receiving solar energy via panels, converting solar energy to electrical power and transferring the electrical power to a motor 21 to aid the movement of the blades in low wind conditions.

Description

(71) Applicant(s):

Mark Roberts

Snowdon Drive, Garden Village, Wrexham, LL11 2UY, United Kingdom (72) Inventor(s):

Mark Roberts (56) Documents Cited:

GB 2464132 A WO 2009/075865 A

GB 2086489 A US 20100266383 A (58) Field of Search:

INT CL F03D

Other: Online: WPI & EPODOC (74) Agent and/or Address for Service:

Mark Roberts

Snowdon Drive, Garden Village, Wrexham, LL11 2UY, United Kingdom (54) Title of the Invention: A wind turbine

Abstract Title: Solar powered VAWT motor with support structure (57) A vertical axis wind turbine 1 comprising a support structure; a blade 3 connected to the support structure pivotable about the turbine axis, where the blade extends radially from the support structure such that the longitudinal axis of the blade is perpendicular to the turbine axis. Other aspects include: Slowing the rotation of a blade of a wind turbine by transferring excess electrical power provided by a generator 5 to an electromagnet of a braking system 21 to cause the polarity of the electromagnet to attract the polarity of a permanent magnets of the shaft to slow its movement. A method of mounting a turbine blade to a rotor by attaching the blade to the rotor in a first direction to provide a force directed towards the rotor using a first fixing means and further attaching the rotor to the blade in a second direction to provide a force directed towards the blade using a second fixing means. A method of operating a wind turbine, comprising receiving solar energy via panels, converting solar energy to electrical power and transferring the electrical power to a motor 21 to aid the movement of the blades in low wind conditions.

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A wind turbine

This invention relates to a wind turbine, in particular a vertical axis wind turbine that may be used for wind energy harvesting.

A wind turbine is a popular technology for generating renewable energy 5 and works by converting the wind’s kinetic energy to electrical power.

Wind turbines can be either vertical axis wind turbines or horizontal axis wind turbines.

Horizontal-axis wind turbines (HAWT) have a main rotor shaft arranged horizontally and an electrical generator at the top of a tower. The tower itself provides turbulence behind it so care must be taken to place the blades up wind of its supporting tower to optimise the turbines performance. This provides the requirement of a steerable turbine to optimise the orientation of the turbine as the wind direction changes. Alternatively special horizontal axis wind turbine designs are required to enable the blades to be positioned downwind to overcome any problems resulting from turbulence.

In contrast Vertical-axis wind turbines (VAWT) have their main rotor shaft arranged vertically and the blades are placed on the same axis as the central shaft. Known vertical turbines include Savonius or Giromill/Darrieus turbines.

Advantageously for VAWT the blades need not be pointed into the wind to be 20 effective. This is particularly beneficial for use on a site where the wind direction is highly variable. Further the generator and gear box can be positioned at ground level making it easier to access for maintenance. Such a vertical axis arrangement has a relatively low rotational speed with the consequential higher torque and therefore requires a higher cost for driving the blades, therefore generally vertical axis wind turbines have a lower power coefficient associated with them. This plus loading on the blade leads to difficulties in analysing and designing the rotor. Further, when a large amount of energy production is required, the turbine design can be very large and most vertical axis wind turbine blades will cover almost the entire length of the vertical axle, which means it can take up as much space at ground level as they do at their higher regions. Since the wind forces tend to be greater at a greater height, the lower regions of the blades receive a lot less wind force than higher up the structure of the turbine, and these lower regions can be detrimental to optimising the power generated by the turbine as they contribute to the net drag. The end result is a turbine that stalls in high winds, provides excessive fatigue in blades due to centrifugal force and provides low wind harnessing capabilities producing lower levels of efficiency.

Many manufacturers have introduced solar panels into their wind turbine 15 designs. However this is mainly applied to HAWTs which have the blade surface configured vertically. Due to the vertical nature of the blades, the solar panels are subjected to a sand blasting effect from oncoming wind. The damage caused by this reduces the efficiency of the solar panels over time. The panels in this orientation also reflect light that can become an irritation and even danger to nearby residents. Generally the solar energy produced is used in conjunction with the energy produced by the main generator.

Therefore, embodiments of the present invention are intended to address at least some of the above described problems and desires. In particular there is provided a design that uses the positive features from both a HAWT and VAWT so as to provide a wind turbine that is efficient, low cost to run and that has an extended lifetime compared to known turbines.

According to a first aspect of the invention there is provided a vertical axis wind turbine comprising:

a support structure rotatable about a turbine axis;

at least one blade having a longitudinal axis, the blade being in mechanical communication with the support structure and being pivotable about the turbine axis, wherein the blade extends radially from the support structure such that 10 the longitudinal axis of the blade is substantially perpendicular to the turbine axis so as to, in use, cause rotation of the blade along a horizontal plane.

The support structure may be coupled to a shaft of a generator.

The vertical axis wind turbine may further comprise a first set of blades coupled to a first support structure.

A second set of blades may be coupled to a second support structure.

The first set of blades and the second set of blades may be configured in a stacked arrangement.

The first set of blades and second set of blades may be spaced apart by a spacer portion.

At least one end of the spacer portion may be cooperably shaped to be received in a recessed portion of the first and/or second support structure.

The radial position of the blades of the second set of blades may be configured to be offset from the radial position of the blades of the first set of blades.

The support structure may be a moveable hub.

The support structure may be a rotor.

The outer perimeter of the rotor may be substantially triangular in shape. The blade set may be formed of three blades and each of the blades may terminate an apex of the triangular shaped rotor.

The blade may comprise a leading surface of the blade, the leading surface being curved or scooped to enable horizontal rotation of the blade when wind flows over the leading surface.

The vertical axis wind turbine may further comprise a trailing edge having 10 an upwardly facing surface located above that of the leading edge.

The blade may further comprise at least one solar energy collector located on at least part of a surface of the blade.

The at least one solar energy collector may be positioned on the leading surface of the blade.

Alternatively, the at least one solar energy collector may be positioned on the surface of the trailing edge of the turbine blade. The solar energy collector may be positioned on both the leading surface and the surface of the trailing edge of the blade.

The solar energy collector may be a solar panel.

At least one solar panel may be electrically coupled to a separate and distinct motor which is mechanically coupled to the support structure.

The generator may be encased within a cradle located above the ground level.

The cradle is located at one end of a pole, with the other end of the pole being secured to the ground or other fixing means.

The turbine may be a direct drive turbine.

The turbine may comprise a brake assembly.

The shaft of the turbine may comprise at least one permanent magnet and the brake system may be configurable to have a magnetic pole opposing that of the permanent magnet so as to, in use, slow down rotation of the shaft causing a braking effect.

The blade may further comprise a channel extending along the length of the interior of the blade for receiving an elongate fixing member that forms a spine for the blade and secures the blade at a first point to the support structure providing a pushing force in the direction of the support structure.

The fixing member may be a bolt and the head of the bolt may be located at the tip of the blade.

The vertical axis wind turbine may further comprise a second fixing member being configured to secure the support structure to the blade at a second point providing a pushing force in the direction of the blade.

An end cap may be configured to be received by the tip of the blade.

In an alternative aspect of the invention there is provided a method of slowing down the rotation of a blade of a wind turbine when the blade is mechanically coupled to a rotatable shaft of a generator, the rotatable shaft having at least one permanent magnet of a pre-defined polarity coupled thereto and the turbine further comprising a braking system having at least one electromagnet, the method comprising:

converting wind energy to rotational energy by means of the blade so as to cause rotation the shaft;

converting rotational energy to electrical power via the generator;

transferring excess electrical power provided by the generator to the electromagnet of the braking system so as to cause the polarity of the at least one electromagnet to attract the polarity of the permanent magnets to slow the movement of the shaft causing a braking effect on the blades of the turbine.

The method further comprises comparing the generated power to a threshold value and when the threshold vale is exceeded, transferring the excess electrical power to the electromagnet of the braking system.

When the blades have been slowed to a predetermined speed and the excess electrical power is below the threshold value, the method may further comprise preventing the electrical power from being transferred to the braking system.

In an alternative embodiment of the invention there is provided a method of mounting a turbine blade to a rotor comprising:

attaching the blade to the rotor in a first direction to provide a force directed towards the rotor using a first fixing means and further attaching the rotor to the blade in a second direction to provide a force directed towards the blade using a second fixing means.

The method may further comprise passing the first fixing means through the interior of the blade so as to reinforce the blade against centrifugal forces on rotation of the blade.

In a further embodiment of the invention there is provided a method of operating a wind turbine having a motor for aiding rotation of the blades of the turbine and having a solar energy receiving means positioned on at least part of the blades comprising, receiving solar energy via the solar energy receiving means, converting solar energy to electrical power and transferring the electrical power to the motor to aid the movement of the blades in low wind force conditions.

Whilst the invention has been described above it extends to any inventive 15 combination of the features set out above, or in the following description, drawings or claims. For example, any features described in relation to any one aspect of the invention is understood to be disclosed also in relation to any other aspect of the invention.

The invention will now be described, by way of example only, with 20 reference to the accompanying drawings, in which:Figure 1 is a perspective view of the wind turbine according to the invention;

Figure 2 is a is a top view of the wind turbine of figure 1;

Figure 3 is a side view of the wind turbine of figure 1;

Figure 4a is a top view of blade with a solar panel applied;

Figure 4b is a perspective view of a blade with a solar panel applied thereto;

Figure 5a is a top view of the rotor;

Figure 5b is a perspective view of the rotor

Figure 6a is a top view of the rotor spacer;

Figure 6b is a perspective view of the rotor spacer;

Figure 7a is a perspective view of the end cap of the blade from a first side;

Figure 7b is a perspective view of the end cap from a second side;

Figure 8 is an exploded top view of the dual mounting system;

Figure 9 is an exploded part perspective view of one end of a blade and the end cap;

Figure 10 is a part exploded perspective view of the other end of the blade and the hub; and

Figure 11 is a perspective view of the motor/brake unit.

In Figures 1 to 3 there is shown the vertical axis wind turbine 1 having a support structure 2 rotatable about a turbine axis. At least one turbine blade 3 20 having a longitudinal axis is provided and configured in mechanical communication with the support structure 2 such that the blade 3 is pivotable about the turbine axis. The blade 3 extends radially from the turbine 1 such that the longitudinal axis of the blade 3 is substantially perpendicular to the vertical turbine axis. Solar panels are positioned on the top surface of the blades as shown, whereby the solar panel/blade arrangement is shown in Figures 4a and

4b.

The blade 3 is coupled to the support structure 2 for example a rotor 2a and in turn the rotor 2a is coupled to a central shaft 4 of a generator 5. The rotor is shown in Figures 5a and 5b. The generator is located at the top of a pole 6 and as such is spaced from the ground This means that the blade 3 is located at or proximal to the top of the central pole and is spaced sufficiently above the ground so as to allow the entire length of the blade 3 to receive the increased wind forces incident at such heights. This differs to standard vertical axis wind turbines where the blade in the position below the rotor experiences lower wind forces. Further, the blade 3 is shaped to permit the wind to continue along its path.

As shown in Figures 1,2 and 3 the wind turbine 1 consists of six blades in total with integrated solar panels 7 incorporated on the top surface of the blades (not shown).

The six blades are split into two equal sets in which three blades 3a, 3b,

3c are connected to an upper rotor 2a’and three blades 3d, 3e, 3f are connected to a lower rotor 2a”. The upper rotor 2a’and the lower rotor 2a” are shown in Figure 4. These rotors are connected to each other via a spacer 8 and are mounted to the vertical shaft 4 of a generator 5 housed within a cradle 9. The cradle 9 is attached to the pole 6. The spacer element 8 is shown in Figure 6a and 6b.

The wind turbine 1 of figures 1 to 3 has been designed to capture as much wind force as possible on the driving side of the blade, whilst making the front of the blade 3 as aerodynamic as possible so that on its return cycle it is not excessively hindered by oncoming wind force. The design of the blades includes a dual mounting process to help relieve the effects of centrifugal force and blade fatigue.

The turbine 1 of Figures 1 to 3 is a direct drive turbine whereby the blades convert wind energy to rotational energy which is transferred to a drive shaft of a generator. This system does not rely on a gear box assembly provided as per conventional wind turbines. Therefore, the blade is attached to the rotor that is coupled to the central shaft of the generator.

The blades 3 are shaped to use greater amounts of wind force whilst still allowing the wind to continue on its path. The blade 3 itself uses a scooped design that is similar to those used in many vertical axis wind turbines but has been modified to have a greater scooped loft at the tip 10 of the blades 3. The blades are of a set length, have a gradually increasing scooped loft on the driving face 11 from mounting edge 12 to tip 10. The tip 10 of the blades 3 are also fitted with end caps 13 as shown in Figure 7 to catch more of the wind force as it turns on its horizontal plane. The increasing scooped loft, end caps 13 and overall shape of the blades 3 are designed specifically for its horizontal rotation. The horizontal layout and the shape and size of the blades also make them ideal for mounting the solar panels (not shown).

The leading (i.e. driving) face 11 of the blade is of an aerofoil like design to reduce drag and improve aerodynamics when the blade 3 is being driven through the air and also against oncoming wind force on its return cycle. The blade 3 has a large trailing edge 14 that helps capture and guide the kinetic energy from the wind towards the scooped loft of the blade 3, driving it down the scooped loft to the tip 10 of the blade increasing the turning torque. The trailing edge 14 has a surface that is raised above the leading face 11. A wall 15 is provided at the interval of the leading face 11 and trailing edge 14. This wall 15 is an extension of the leading face 11. The leading face 11 has a curved surface which becomes gradually steeper towards the wall 15, until it forms the wall 15, whereas the surface of the trailing edge 14 or rearward region is substantially flat and faces upwards from the ground.

The tips 10 of the blades 3 are fitted with the end caps 13 to assist with 10 aerodynamics and to help capture wind force, whilst at the same time allowing the wind to escape the lofted area and reduce turbulence. The end caps 13 are secured to the blade 3 via bolts 16. Moulded caps (not shown) are placed over the bolts 16 that secure the end caps 13 to the blades 3, making them more aerodynamic and giving them a more streamline appearance.

The solar panels (not shown) are provided on both the leading face and surface of the trailing edge 14 of the blades 3. The solar panels (not shown) are not provided on the wall region 15 which is substantially perpendicular to the horizontal plane of the blade 3.

The blades 3 were modelled using Autodesk® Inventor®, an Auto CAD 20 program that converts a 2D drawing into a 3D model. The vertical axis wind turbine is suitable for use on a domestic scale. The shape of the blades is based on the shape of birds and aquatic animals. The optimised shape has been achieved using an iterative process that was repeated until the blades had both an aerodynamic and streamline leading face 11 whilst also having a large area to catch oncoming wind force. It was found that the scooped gradient layout of the blade 3 offered the best approach at guiding wind force to the tip 10 of the blade 3 where it is needed most, as more force at the tip 10 of the blades 3 equates to more leverage in an effort to turn the rotors 2a’, 2a” and main shaft 4.

The end caps 13 are an added addition to continue the capture of the wind force whilst minimising the creation of unwanted turbulence.

To ensure the turbine blades 3 can withstand the wind force applied thereto a dual mounting arrangement as shown in Figures 8 to 10 is applied. The dual mounting process comprises of mounting the blades to the rotor in two different directions. The first end of the blade 17 is mounted to the rotor using a fixing means 18, for example bolts 18a. The end of the bolts 18a are firstly passed through an aperture in the rotor 2a and then into the first end 17 of the blade 3 where the end of the bolts 18a are retained as shown in Figure 8. This draws the first end 17 of the blade 3 flush with the rotor 2a giving a pulling force upon the blade 3 towards the rotor 2a. Further, a compression plate 19 is fitted to the tip 10 of the blade 3 in which a second fixing means 20, for example a second bolt assembly 20a is applied such that the end of the second bolt assembly is passed through the compression plate, then is inserted into the tip end of the blade, through an internal portion of the blade until the end of the bolt exits the blade and then passes into an aperture located in the rotor where the end of the bolt is retained. This is shown in Figure 9. This second bolt assembly

20a extends the entire length of the blade 3 forming a spine like support adding to the blades 3 overall strength. The second bolt assembly 20a is threaded into the rotor 2a at the end of the blade 3 and when tightened, provides a pushing force upon the blade 3 in the direction of the rotor 2a. The push and pulling forces placed upon the blade 3 using this dual mounting arrangement allows the blade to withstand the centrifugal forces it is subjected to when in use. The compression plate 19 is fitted to cover a greater surface area to be compressed when the bolt is tightened and to prevent the bolt from crushing its way into the tip 10 of the blade 3. The bolts are fitted with anti-vibration washers (not shown) to prevent them from working loose and to help eliminate unwanted vibrations.

The wind turbine 1 is fitted with a dual Motor and Brake Unit 21 as shown in Figure 11. The motor and brake unit 21 consists of two sets of stators, one 10 upper stator 22 and one lower stator 23. The stators 22, 23 are of an electromagnetic design, surrounding permanent magnets (not shown) attached to the central shaft of the wind turbine. The upper stator 22 is of a standard motor design and is powered by the energy produced by the integrated solar panels (not shown). This assists in turning the blades 3 of the turbine 1 and helps make rotation possible in low wind speeds.

The motor/brake 21 is an independent unit that is separate to the main generator 5. It is positioned on top of the cradle that houses the main generator. Despite the motor and brake unit 21 being a complete unit the upper section of the motor is in fact separately attached to the base of the rotor 2a. This is to make the design more efficient, low maintenance and cost effective. The motor and brake unit 21 is mounted to the cradle in a static position. The power needed for the motor comes from the solar panels which are on a rotating axis. Usually to pass electricity from a rotating axis to a static plane requires the use of a slip ring. This slip ring is an added expense and comes with its own set of draw backs such as, bushes that would need to be replaced many times over the wind turbines life span.

Instead, the upper section of the motor and brake unit 21 contains the copper windings (not shown) and has direct access to the power produced by the solar panels (not shown). This eliminates the need for a slip ring. As the windings are energised the upper brake section begins to rotate and since it is attached to the rotors (2a’, 2a”), will in turn cause them to rotate. As the rotors (2a’, 2a”) are attached to the main shaft 4, the upper section of the motor and brake unit 21 slides over the lower section and completes the motor and brake unit assembly 21.

The motor is located with the brake to enable the assembly to be compact. The motor and brake unit 21 are made of a slotless construction where the copper wires are wound against the laminations and held with adhesive. This design yields smooth rotation and virtually eliminates cogging. Instead of winding copper wires through slots in a laminated steel stack as is the case with conventional brushless motors, slotless motor wires are wound against siliconsteel laminations. They are then encapsulated in epoxy resin to maintain their orientation with respect to the stator laminations and housing assembly. This configuration, which replaces the stator teeth, eliminates cogging and results in quiet operation. These types of motors are used when a smooth and quiet operation is needed such as in a record player’s turn table. As the cogging effect has been eliminated in this type of motor, it will spin freely and unhindered even when the motor is receiving no power. This allows the blades to turn with little or no magnetic resistance when not in use. These factors make the motor the ideal choice for a domestic wind turbine.

The lower stator 23 is constructed with the copper windings all being wound in the same direction and with magnets with identical poles facing them.

When the lower stator 23 is energised the electromagnets produce opposite poles to the permanent magnets located on the central shaft 4 causing them to be attracted to each other. The attraction of the magnets causes a braking effect on the central shaft 4 and acts as a braking mechanism. The electricity generated can be transferred to an energy storage means, for example a rechargeable battery. When the maximum storage capacity of the batteries (not shown) is reached or excessive power generation occurs due to the presence of high winds, the energy produced is sent to the lower stator (electromagnetic brake). The brake then slows the rotational speed of the wind turbine by using the excessive power, whereby the excess power is diverted by means of an automatic control circuit (not shown).

. As the rotational speed of the blades 3 reduces, less energy will be produced and the electromagnet will release its grip upon the central shaft 4 of the wind turbine and the brake portion of the motor and brake unit 21 can be said to be deactivated. At this point the wind turbine 1 starts to gain rotational momentum once again until the brake is activated again. This on and off braking cycle allows the wind turbine 1 to continuously turn in high force winds. This continuous rotation helps to prevent the wind turbine from being damaged by high winds, as the spinning of the blades 3 are able to absorb the force of the oncoming winds as it is converted into kinetic energy.

Therefore, the wind turbine 3 has a mechanical braking system that is formed of an independent electromagnetic brake that is configured to create greater torque on the drive shaft to enable the production of enough torque in to slow the rotation of the blades when they experience strong winds. Sensors (not shown) are provided to monitor the rotational speed of the drive shaft 4..

The electrical power provided by the turbine 1 is transferred to a larger energy storage device at the base of the turbine or it is transferred by cabling to an energy storage device away from the turbine site.

The solar panels (not shown) are positioned on the top surface of the 10 horizontal blades such that they lie flat facing upwards (away from the ground). As this design of wind turbine does not need to be turned into the path of oncoming wind, it allows the solar panels to constantly face upwards. This will allow the solar panels to capture sun light regardless of where the sun may be positioned in the sky. This configuration also makes the solar panels less susceptible to damage from debris carried by strong winds. Any glare from the solar panels would be reflected upwards and away from domestic or other dwelling and the residents housed within.

In known designs the solar energy created is used in conjunction with the energy produced from the main generator 5, using both wind and solar in an attempt to raise the efficiency of the wind turbine 1. However, the main generator has the potential of producing a much greater and reliable power source than the solar panels (not shown). Therefore in Figures 1 to 3 the solar panels (not shown) are used as a power source for the independent motor in the motor and brake unit 21 which is connected to the main drive shaft 4. This motor assists in the turning of the blades and increases the efficiency of the energy produced from the main generator 5. Although the solar panels (not shown) may not produce enough energy to turn the blades 3 on their own, the torque applied to the drive shaft 4 assists in the spinning of the blades 3. Consequently, much less effort from wind force is needed to cause the blades 3 to rotate. This is analogous to taking a standard steering system of a vehicle and turning it into power steering. With the addition of this solar powered motor of the motor and brake unit 21, the turbine 1 commences rotation at much lower wind speeds. As the wind speeds drop, the motor will extend the turning momentum of the turbine

1 producing more power for longer periods. As with the brake, additional sensors and computer processors are included to activate the motor at precise moments.

This provides a much smoother and efficient operation of the turbine that is capable of extending the life of the product compared to other known commercial wind turbines. The Wind Turbine of the invention is more effective at capturing oncoming wind force. It is effective in both high and low wind speeds and is both streamline and of a sturdy construction making it quieter, less prone to damage and more effective at producing energy. With the inclusion of the solar panels it is more effective at producing energy as it is able to harness energy from both the wind and sun. The energy from the sun is used as a power source to assist the main motor that drives the blades.

Various modifications to the principles described above would suggest themselves to the skilled person. For example, the brake of the motor and brake unit 21 may be of a mechanical variety (for example brake pads applied to the central shaft) that is triggered by the excessive power passing to the brake assembly.

For example the solar panels (not shown) may not be provided on the turbine itself and may instead be provided close to the turbine.

The extra energy provided to the motor may be provided by an energy generating means differing to solar energy.

The turbine 1 may be controlled remotely by a user.

More rotors 2a’, 2a” could be added to the design with each rotor being slightly offset to the next to cover a greater area of wind catchment. This is 10 particularly applicable for areas with low wind speeds but, this is at a trade off with cost and stress due to the extra weight on the design.

Also a set of blades may consist of less than three blades, or more than three blades as desired. For example a four bladed single rotor design or two blades on the upper rotor and two blades on the lower rotor, set at opposites to each other would also be feasible, however it is believed that these assemblies are not as effective as the six bladed design of Figure 1.

The cradle may alternatively be attached to the top of a tower, or the motor and generator may be located at ground level if preferred.

Whilst the turbine is based on a more domestic scale of wind turbine and is direct drive, it is feasible for a a gearbox to be added should the design be scaled up to a much larger turbine that is needed to satisfy a higher demand for electricity.

The other end of the pole 6 may not be placed directly on the ground and may instead be located on an intermediary structure, for example a building or other man made structure.

For the benefit of doubt, an upwardly facing surface means one that faces 5 away from the ground on which the turbine is positioned upon.

Whilst it is possible to install the solar panels on the ground facing side of the blades and to reflect the sunlight via a mirror or other means towards the solar panels, such an alternative design is expected to be costly and would incur significant losses of power.

Claims

1. A vertical axis wind turbine comprising:

a support structure rotatable about a turbine axis;

at least one blade having a longitudinal axis, the blade being in mechanical communication with the support structure and being pivotable about the turbine axis, wherein the blade extends radially from the support structure such that the longitudinal axis of the blade is substantially perpendicular to the turbine axis so as to, in use, cause rotation of the blade along a horizontal plane.

2. A vertical axis wind turbine according to claim 1, wherein the support structure is coupled to a shaft of a generator.

3. A vertical axis wind turbine according to claim 1 or claim 2 further comprising a first set of blades coupled to a first support structure.

4. A vertical axis wind turbine according to claim 3 further comprising a second set of blades coupled to a second support structure.

5. A vertical axis wind turbine according to claim 4, wherein the first set of blades and the second set of blades are configured in a stacked arrangement.

6. A vertical axis wind turbine according to claim 4 or claim 5, wherein the first set of blades and second set of blades are spaced apart by a spacer portion.

7. A vertical axis wind turbine according to claim 6, wherein at least one end of the spacer portion is shaped to be received in a cooperatively shaped recessed portion of the first and/or second support structure.

8. A vertical axis wind turbine according to any of claims 4 to 7, wherein

5 the radial position of the blades of the second set of blades are configured to be offset from the radial position of the blades of the first set of blades.

9. A vertical axis wind turbine according to any preceding claim, wherein the support structure is a moveable hub.

10 10.A vertical axis wind turbine according to any preceding claim, wherein the support structure is a rotor.

11. A vertical axis wind turbine according to claim 10, wherein the outer perimeter of the rotor is substantially triangular in shape.

12. A vertical axis wind turbine according to claim 11 when dependent of

15 claim 3 or claim 4, wherein the blade set is formed of three blades and each of the blades terminates an apex of the triangular shaped rotor.

13. A vertical axis wind turbine according to any preceding claim, wherein the blade comprises a leading surface, the leading surface

20 being curved or scooped to enable horizontal rotation of the blade when wind flows over the leading surface.

14. A vertical axis wind turbine according to claim 13, further comprising a trailing edge having an upwardly facing surface located above that of the leading edge.

15. A vertical axis wind turbine according to any preceding claim, the blade further comprising at least one solar energy collector located on at least part of a surface of the blade.

16. A vertical axis wind turbine according to claim 15 when dependent

5 upon claim 13 comprising at least one solar energy collector positioned on the leading surface of the blade.

17. A vertical axis wind turbine according to claim 15 or 16 when dependent on claim 14 further comprising at least one solar energy collector positioned on the trailing edge of the turbine blade.

10

18. A vertical axis wind turbine according to any of claims 15 to 17, wherein the solar energy collector is a solar panel.

19. A vertical axis turbine according to claim 18 wherein the at least one solar panel is electrically coupled to a separate and distinct motor which is mechanically coupled to the support structure.

15 20. A vertical axis wind turbine according to claim 2, wherein the generator is encased within a cradle located above the ground level.

21. A vertical axis wind turbine according to claim 20, wherein the cradle is located at one end of a pole, with the other end of the pole being secured to the ground.

20 22.A vertical axis wind turbine according to any preceding claim, wherein the turbine is a direct drive turbine.

23. A vertical axis wind turbine according to any preceding claim, further comprising a brake assembly.

24. A vertical axis wind turbine according to claim 23 when dependent on claim 2, wherein the shaft comprises at least one permanent magnet and the brake system is configurable to have a magnetic pole opposing that of the permanent magnet so as to, in use, slow down

5 rotation of the shaft causing a braking effect.

25. A vertical axis wind turbine according to any preceding claim, wherein the blade further comprises a channel extending along a longitudinal axis of the interior of the blade for receiving an elongate fixing member so as to form a spine for the blade and to secure the

10 blade at a first point to the support structure providing a pushing force in the direction of the support structure.

26. A vertical axis wind turbine according to claim 25, wherein the fixing member is a bolt and the head of the bolt is located at the tip of the blade.

15

27. A vertical axis wind turbine according to claim 25 or 26, further comprising a second fixing member to secure the support structure to the blade at a second point, the second fixing member being configured to provide a pushing force in the direction of the blade.

28. A vertical axis wind turbine according to any preceding claim, further 20 comprising an end cap configured to be received by the tip of the blade.

29. A method of slowing down the rotation of a blade of a wind turbine when the blade is mechanically coupled to a rotatable shaft of a generator, the rotatable shaft having at least one permanent magnet of a pre-defined polarity coupled thereto and the turbine further

5. A method of operating a wind turbine having an electric motor for aiding rotation of the blades of a wind turbine and having a solar energy receiving means positioned on at least part of the blades comprising, receiving solar energy via the solar energy receiving means, converting solar energy to electrical power and transferring the electrical power to the motor to aid the movement of the blades.

20 11 17

Application No: GB1619730.3 Examiner: Mr Robert Arnold

5 comprising a braking system having at least one electromagnet, the method comprising:

converting wind energy to rotational energy by means of the blade so as to cause rotation of the shaft;

converting rotational energy to electrical power via the generator;

10 transferring excess electrical power provided by the generator to the at least one electromagnet of the braking system so as to cause the polarity of the at least one electromagnet to attract the polarity of the permanent magnets so as to slow the movement of the shaft causing a braking effect on the blades of the turbine.

15

30. A method according to claim 29, further comprising comparing the generated power to a threshold value and when the threshold vale is exceeded, transferring the excess electrical power to the electromagnet of the braking system.

31. A method according to claim 30, wherein in the case that the blades

20 have been slowed to a predetermined speed and the excess electrical power is below the threshold value, the method further comprising preventing electrical power from being transferred to the braking system.

32. A method of mounting a turbine blade to a rotor comprising:

attaching the blade to the rotor in a first direction to provide a force 5 directed towards the rotor using a first fixing means and further attaching the rotor to the blade in a second direction to provide a force directed towards the blade using a second fixing means.

33. A method according to claim 32, further comprising passing the first

10 fixing means through a channel located within the interior of the blade and orientated substantially in line with or parallel to the longitudinal axis of the blade so as to reinforce the blade against centrifugal forces which occur on rotation of the blade.

34. A method of operating a wind turbine having a motor for aiding

15 rotation of the blades of the turbine and having a solar energy receiving means positioned on at least part of the blades comprising, receiving solar energy via the solar energy receiving means, converting solar energy to electrical power and transferring the electrical power to the motor to aid the movement of the blades in

20 low wind force conditions.

35. A turbine assembly as hereinbefore described in reference to the accompanying drawings.

36. A method as hereinbefore described above in reference to the accompanying drawings.

Amendments to the claims have been filed as follows :20 11 17

1. A Solar Powered VAWT Motor comprising:

An electric motor consisting of two independent assemblies.

2. A Solar Powered VAWT Motor according to claim 1, wherein the Stator consisting of Permanent Magnets housed within a frame work and attached to the main generator or its associated housing of a wind turbine and secured in a static position.

3. A Solar Powered VAWT Motor according to claim 1, wherein the Rotor that consists of copper windings housed within a casing and attached to the underside of the blade assembly's lowest rotor of a wind turbine.

4. A Solar Powered VAWT Motor that is powered by solar panels or an energy storage device placed upon the blade assembly of a wind turbine.