Wind turbine with friction drive power take off on outer rim
A wind turbine has multiple blades (10) that are mounted on a shaft (19) with a ring around a circumference of the blades. There are tires (18) that are arranged to be in contact or out of contact with the ring. The tires draw generators when the tires are in contact with the ring and the ring is rotating. A controller monitors the wind conditions and controls the turbine to produce electricity or other-energy output or to shut down if the wind falls below a predetermined level.
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1. Field of Invention
This invention relates to a wind turbine and method of operation thereof for producing energy and, more particularly, to a wind turbine having multi-blades (for example eight to twenty), and a ring around the circumference thereof, the ring driving energy producing equipment. The blades are shaped with airfoils to produce maximum power coefficient.
2. Description of the Prior Art
Wind turbines, including windmills, are known and are used to power energy production equipment including generators, compressors or pumps, as well as other devices. It is known to have the wind turbine connected to a shaft and the rotational energy in the shaft is then used to drive the energy producing equipment. Windmills or wind turbines have gearboxes to transfer the energy from the blades through the shaft to energy producing equipment. Some wind turbine manufactures are using a large diameter direct drive generator connected directly to the shaft and running at low rotational speed. Wind turbines with large rated electrical output require (<3 MW) large gearboxes and generators. This can result in heavy and costly power transmission and energy production equipment. It is known to use wind turbines to produce electrical energy. Fixed and variable speed wind turbines are used to produce electricity with the same frequency as the grid. Fixed and variable speed wind turbines have certain advantages and disadvantages. Variable speed wind turbines have advantages of reducing the dynamic loads on the power transmission systems and have higher power coefficients than fixed speed wind turbines. Variable speed wind turbine use several methods and systems to obtain the same frequency as the grid system of an electrical utility. These systems are more costly than those used in fixed speed wind turbines. Variable speed operation will allow the wind turbine to start producing electricity at lower wind speeds and hence collect more energy. With variable speed wind turbines, there is a difficulty of producing electricity with the same frequency as the grid because the wind velocity constantly changes and therefore the speed of rotation of the blades of the wind turbine varies. With constant speed wind turbines, the frequency of the electricity produced can match the frequency of the grid, but difficulty arises in maintaining a constant speed with variable wind conditions. Further, electrical energy cannot be produced by any wind turbine during periods when the wind is not blowing or is not blowing at a sufficient velocity to rotate the rotor of the wind turbine.
Wind power is renewable and is a green energy source that is highly desirable as it does not pollute.
SUMMARY OF THE INVENTIONIt is an object of the present invention to provide a wind turbine that can be controlled to operate energy producing equipment at variable speed rate of speed. It is further object of the present invention to provide a wind turbine without using a step up gearbox.
A wind turbine for producing energy has a rotor on a shaft. The rotor supports a plurality of blades and is rotatably mounted on the shaft. The blades each have a tip, there being a plurality or tips on the turbine. The tips are connected to support a ring that extends around a circumference formed by the tips. The ring rotates with the blades, the ring having a front and rear surface with rotators mounted to removably contact the ring on the front and rear surfaces. Each of the rotators is connected to energy producing equipment. The rotators rotate with the ring when the ring rotates, thereby driving the energy producing equipment. The turbine is controlled by a controller.
A wind turbine for producing energy has a rotor on a stationary shaft. The rotor supports a plurality of blades shaped with airfoil sections and is rotatably mounted on the stationary shaft via a hub and a bearing. The blades each have an outer tip, there being a plurality of outer tips on the wind turbine. The tips are connected to a ring that extends around a circumference formed by the tips. The ring has front and rear surface and rotators are mounted to removably contact the ring on the front and rear surfaces. Each of the rotators is connected to energy producing equipment. When the ring rotates and the rotators are in contact with the ring, the rotators also rotate, thereby driving the energy producing equipment.
Preferably, the energy producing equipment is selected from the group of a generator, a compressor and a pump.
Still more preferably, the rotators are mounted on a cart with rails having its center of rotation at the center of the tower base circle. The cart being rotatable to move with the wind turbine either toward or away from the wind.
A method of operating a wind turbine for producing energy, said turbine having a rotor on a shaft, said rotor supporting a plurality of blades and being rotatably mounted on said shaft, said blades each having a tip, there being a plurality of tips on said turbine, said tips being connected to support a ring that extends around said tips, said ring rotating with said blades, said ring having a front and rear surface with rotators mounted to removably contact said ring on said front and rear surfaces, each of said rotators being connected to energy producing equipment, said rotators rotating with said ring when said ring rotates, said turbine being controlled by a controller, said method comprising operating said turbine by continuously monitoring wind conditions, adjusting yaw, blade orientation and pressure and number of rotators against said ring or removal of rotators from said ring to produce power output whenever said wind conditions are sufficient.
BRIEF DESCRIPTION OF THE DRAWINGS
In
In
The stationary shaft 8 is fixed on a bedplate 13 by a front mounting 9 and a rear mounting 11. The bedplate 13 is mounted on a tower 17, which is fixed to a foundation 27. The foundation 27 is constructed into the ground 30.
In
In
The wind turbine of the present invention has the capacity to collect and transmit power in the range of 50 kilowatts to 7.5 megawatts and has a low capital cost when compared to conventional power wind turbines rated in the same range. The wind turbine will rotate with relatively low rpm when compared to conventional wind turbines (rpm will depend on the number of blades, when using 20 blades the rotational speed is between 1 and 5 rpm). This low rotational speed will provide long service time for the rotating parts requiring less maintenance, produce less noise than conventional wind turbines, and the turbine has better control characteristics than conventional designs. The wind turbine of the present invention can be designed to compress air and to store that compressed air for use during peak hours for the electrical system. The number of compressors used depends on the power delivered by the wind turbine and the capacity of each compressor. Compressed air can be stored in underground storage pipes, tanks, caverns or in the body of the wind turbine tower. Heat exchangers can be used to extract the heat from the compressed air storage and re-provide the same heat for the compressed air later for the regeneration process.
The wind turbine of the present invention can be used to drive an air-water engine consisting of several cylinders. Air-water systems have been previously described. A Pelton wheel is preferably used with the air-water system to produce electricity as described in U.S. Pat. Nos. 6,672,054 and 6,718,761.
A single rotator can be designed to drive different types of energy production equipment. For example, a rotator could be alternatively connected to a pump, compressor and generator with a controller to control which type of energy producing equipment is being driven at any particular time. The wind turbine can be constructed to be strong enough to have the rotators contact one surface of the ring only. Also, the ring can be designed with projection and indentations thereon corresponding to projections and indentations on the rotators. The ring could also be designed in separate parts with the front surface located on a separate component from the back surface.
A control system for the wind turbine is as follows:
-
- Operational sequence system.
- The system will receive external signals according to the operating conditions, above all the wind conditions and operator's intentions, which will determine the set values for the control system.
- Objectives of the operational sequence system are as follows:
- 1—Ensure fully automatic operation.
- 2—Recognize hazards and activate the corresponding safety systems.
- 3—Meet special requirements of the operator.
- Supervisory systems controls.
- The system will take into consideration the following:
- 1—Yaw motion.
- 2—Speed and power output.
- 3—Mode of operation.
The control system will take into consideration the following:
- Operational sequence system.
1—Wind Measurement System:
-
- Operational sequence and yawing requires measuring the wind speed and direction.
- Electrical motor-driven yawing system is proposed for the multi blade wind turbine, which requires information about wind direction.
- Operational sequence requires the wind speed information in order to switch between different modes of operation.
- Measuring of the wind speed could be preformed indirectly by means of the electrical output. The rotor itself is the only representative wind measuring instrument of a turbine.
2—Yaw Control:
-
- The wind measuring system provides a mean value of the wind direction over a period of ten seconds. This value is compared with the instantaneous azimuth position of the nacelle every two seconds. If the deviation remains below 3 degrees, the yaw system will not be activated. If the determined yaw angle is above this value, the time for correction is determined by a pre-programmed function. An operating diagram for the yaw is shown in
FIG. 24 . - If the yaw angle is small (0 to 20 degrees), yawing is carried out within 60 seconds.
- If the yaw angle is 20 to 50 degrees, yawing is carried out within 20 seconds.
- If the yaw angle is large (exceeds 50 degrees), yawing is carried out immediately.
- The rotor yaw speed is low and to be determined after taking into consideration the gyroscopic moments. Since the yaw speed is the same for small and large yaw movements of the turbine, large movements will take much longer to complete than small movements. For small movements, the commencement of yawing is delayed as the wind may change direction within the delay period. For large movements (exceeding 50 degrees), the yaw movement commences immediately.
- The wind measuring system provides a mean value of the wind direction over a period of ten seconds. This value is compared with the instantaneous azimuth position of the nacelle every two seconds. If the deviation remains below 3 degrees, the yaw system will not be activated. If the determined yaw angle is above this value, the time for correction is determined by a pre-programmed function. An operating diagram for the yaw is shown in
3—Power and Speed Control by Rotor Blade Pitching when using a Blade Pitching Mechanism:
The objective is to obtain a stable operating point by the following means:
-
- a—Controlling the blade pitch, which will control the rotor's primary energy.
- b—Control of the generator voltage and reactive power.
- c—Loading and unloading of the generators.
Extremely brief fluctuations of less than few seconds are reduced by the rotor blades, friction ring, and actuating elements mass inertia. Combined speed and power control system is proposed for the control of the Multi Blade wind turbine.
4—Mechanical Drive Train:
The inertia of the rotating masses including:
-
- a—The Rotor.
- b—The Friction ring.
- c—The Rotator and shaft
- d—The Generator Rotor.
The stiffnesses, the damping behavior, and vibration behavior are different than those of a conventional wind turbine as the power transmission system is unconventional using a friction drive and multi-generator system.
5—Full and Partial Load Operation:
-
- In full load operation the pitch control is active (when using a pitch mechanism), so that rotational speed and power can be adjusted to the nominal values. The speed controller can be provided with a degree of insensitivity to reduce the number of pitching processes.
- When not using a pitch mechanism, the blades will be stall regulated. Hence, the angle of the blades will be high enough at high wind speeds to ensure stall to reduce the loads on the blades.
- At partial load, control of the power output and rotor speed is carried out by variation of the generator torque and loading and unloading of the Tire-Generator mechanisms (if the mechanisms is not in contact with the friction ring all the time).
- Using the MPPT (Maximum Point Power Tracking) process approach to control the rotor speed achieving the optimal rotor power coefficient. This is achieved by determining the set point for the power maximum by incremental speed variation, in the form of a scanning process.
Control System Actions:
-
- 1—Acquisition of the input data necessary for operational sequence as wind speed and wind direction.
- 2—Automatic operational sequence, with manual operation for special cases.
- 3—Activation of the safety and emergency systems taldng into consideration shutdown of the rotor even with out electric control system.
- 4—Adaptation to operation on the grid.
Operational Cycle:
Operational cycle includes the following:
-
- System check at stand still: checking of the operational status of the most important systems. The rotor is arrested by the parking brake and pitch angle (when pitch mechanism is used). If no faults are indicated in the system check, the turbine is ready for further progress in the operational cycle.
- Yawing: if the system check is positive, the yaw system is activated, the rotor still being parked. The turbine is yawed to the wind direction (turbine yawing includes moving the Rotor head and the Tire-Generator Mechanism Cart at the same time) and it is checked whether the wind speed is within the operating range of 4 to 25 m/sec.
- Start up: pitching of the rotor blades into the starting position (when using a pitching mechanism), subsequently the mechanical rotor brake is released. The rotor stars to turn and accelerates up to the synchronization speed of the generator, corresponding to 90% of the nominal speed. Start loading of the Tire-Generator Mechanism (Tire-Generator mechanisms may be in contact with the friction ring all the time or may be loaded as the wind speed increase). The blade pitch angle is controlled according to a preset speed increase (when using a pitch mechanism).
- Normal operation: if the generator's connection to the grid has been established the power output into the grid begins (cut-in wind speed). The turbine operates at partial load if the wind is below rated value. Under these conditions the pitch angle is set to a predetermined value (when using a pitch mechanism), which is the angle of the best compromise close to the optimum in the rotor power characteristics (variable blade pitch operation under partial load may be required). When operating at full load, the blade pitch is then controlled such that the rated power is not exceeded. When using a stall regulation as the state of pitch mechanism, the blades will stall to avoid overrating the wind turbine and this will ensure that the rated power is not exceeded.
- Shut-down: if the wind speed drops below the cut-out wind speed or if loaded operation is to be interrupted, the rotor will be brought to the standstill. During the shutdown process the rotor blades are pitched in order to achieve a defined speed decrease (when using a pitch mechanism). The generators are taken off the grid, within the range of 92% to 90% of the rated speed. Rotor standstill is achieved by setting the speed set-point value to zero. The rotor blades pitch to an angle of approximately 80 degrees (when using a pitch mechanism). This brakes the rotor aerodynamically to a low idling speed. Complete standstill is achieved by applying the mechanical brake. When using stall to regulate the blades, the turbine is yawed out of the wind direction. This will reduce the rotor speed to idling speed. Complete standstill is achieved by applying the mechanical brake.
- The method of operating the wind turbine to produce energy can vary. The turbine is preferably operated as a variable speed turbine and the controller is used to control the operation of the turbine in light of the wind conditions. The controller preferably continually monitors the wind conditions and when the conditions are sufficient to generate energy from the wind turbine, the controller automatically adjusts the yaw, orients the blades and when the blades are rotating at sufficient rpm, places the appropriate number of rotators with the appropriate pressure against the ring. In stronger wind conditions, the controller will place more rotators against the ring and in weaker wind conditions, the controller will remove some or all of the rotators from the ring. When wind conditions are not sufficient to generate energy, the controller will shut the turbine down by applying a mechanical brake to the turbine to stop the blades from rotating and also orienting the blades and adjusting the yaw of the turbine to reduce the effect of the wind. As the wind conditions improve, the controller will again release the brake, adjust the yaw and orient the blades to cause the blades to rotate at sufficient speed to generate energy. The controller will then place the rotators in varying numbers against the ring and remove rotators as required as the wind conditions continue to vary. The process will be repeated as the turbine continues to operate.
- Numerous variations can be made to the invention within the scope of the attached claims. For example, the front and rear surfaces of the ring can have a plurality or alternating ridges and indentations thereon corresponding to alternating indentations and ridges on said rotators. The wind turbine has a controller that automatically controls the operation of the turbine.
Claims
1. A wind turbine for producing energy comprises a rotor on a shaft, said rotor supporting a plurality of blades and being rotatably mounted on said shaft, said blades each having a tip, there being a plurality of tips on said turbine, said tips being connected to support a ring that extends around a circumference formed by said tips, said ring rotating with said blades, said ring having a front and rear surface with rotators mounted to removably contact said ring on said front and rear surfaces, each of said rotators being connected to energy producing equipment, said rotators rotating with said ring when said ring rotates, thereby driving said energy producing equipment, said turbine being controlled by a controller.
2. A wind turbine as claimed in claim 1 wherein said controller is connected to continuously monitor wind conditions and to control a yaw of the turbine, orientation of the blades, number of rotators in contact with said ring in response to changing wind conditions.
3. A wind turbine as claimed in any one of claims 1 or 2 wherein said turbine is a variable speed turbine.
4. A wind turbine as claimed in claim 1 wherein there are brakes that can be operated to stop or slow down a speed of rotation of said turbine.
5. A wind turbine as claimed in claim 1 wherein the number of blades ranges from substantially eight to substantially twenty.
6. A wind turbine as claimed in claim 1 wherein said rotators are at least one of tires, tires made of rubber, steel wheels and metal wheels.
7. A wind turbine as claimed in claim 1 wherein said front and rear surfaces have a plurality of projections and indentations thereon corresponding to indentations and projections respectively on said rotators.
8. A wind turbine as claimed in claim 7 wherein said tires are mounted to power a generator that produces electricity.
9. A wind turbine as claimed in claim 7 wherein said ridges and indentations on said rotators are mounted to drive a generator.
10. A wind turbine as claimed in claim 1 wherein the blades are constructed so that a longitudinal orientation of said blades can be adjusted to control a speed of rotation with varying wind conditions.
11. A wind turbine as claimed in claim 1 wherein said shaft is supported by a tower.
12. A wind turbine as claimed in claim 1 wherein said wind turbine is mounted on a turntable so that said turbine can be oriented in response to changes in wind direction.
13. A wind turbine as claimed in claim 12 wherein said turntable has wheels thereon.
14. A wind turbine as claimed in claim 13 wherein there is a rail mounted on a base and said wheels ride on said rail.
15. A wind turbine as claimed in claim 1 wherein said blades have an air foil construction.
16. A wind turbine as claimed in claim 14 wherein there are guides to guide said wheels on said rail.
17. A wind turbine as claimed in claim 16 wherein there are retention means to maintain said wheels on said rail.
18. A wind turbine as claimed in claim 14 wherein there are guides and retention means connected to said wheels beneath said rail to hold said wheels on said rail and prevent said wheels from running off said rails.
19. A wind turbine as claimed in claim 1 wherein said energy producing equipment is one or more selected from the group of generators, compressors and pumps.
20. A wind turbine as claimed in claim 11 wherein said blades, rotor, shaft, tower, rotators and energy producing equipment are mounted on a turntable to enable said turbine to be oriented to respond to changes in wind direction.
21. A method of operating a wind turbine based on conditions of said wind, said turbine having a rotor on a shaft, said rotor supporting a plurality of blades and being rotatably mounted on said shaft, said blade each having a tip, there being a plurality of tips on said turbine, said tips being connected to support a ring that extends around a circumference formed by said tips, said ring having a front and rear surface with rotators mounted to removably contact said ring on said front and rear surfaces, each of said rotators being connected to energy producing equipment, said rotators rotating with said ring when said ring rotates, thereby driving said energy producing equipment, said turbine having a controller, said method comprising operating said turbine to have said controller monitor wind conditions, said controller:
- (a) when said wind conditions are sufficient to generate energy from said wind turbine;
- (b) adjusting the yaw, orienting the blades, placing rotators in varying numbers against said ring or removing rotators from said ring to have said turbine generate energy; and
- (c) when said wind conditions are not sufficient to generate energy, operating said turbine to stop said blades from rotating.
22. A method of operating a wind turbine for producing energy, said turbine having a rotor on a shaft, said rotor supporting a plurality of blades and being rotatably mounted on said shaft, said blades each having a tip, there being a plurality of tips on said turbine, said tips being connected to support a ring that extends around said tips, said ring rotating with said blades, said ring having a front and rear surface with rotators mounted to removably contact said ring on said front and rear surfaces, each of said rotators being connected to energy producing equipment, said rotators rotating with said ring when said ring rotates, said turbine being controlled by a controller, said method comprising operating said turbine by continuously monitoring wind conditions, adjusting yaw, blade orientation and pressure and number of rotators against said ring or removal of rotators from said ring to produce power output whenever said wind conditions are sufficient.
Type: Application
Filed: Apr 19, 2004
Publication Date: Dec 7, 2006
Applicant:
Inventors: Paul Merswolke (Bogner), Charles Meyer (Bogner)
Application Number: 10/553,454
International Classification: B63H 1/06 (20060101);