Patent Publication Number: US-2007110579-A1

Title: Vertical axis wind turbine energy converter (VAWTEC)

Description:
FIELD OF THE INVENTION  
      The device relates generally to the field of windmills or wind turbines for the production of electricity. More specifically it relates to the field of vertical axis turbines.  
     BACKGROUND OF THE INVENTION  
      Renewable and non-polluting sources of energy are currently in high demand. Traditional sources of generating energy such as the combustion of fossil fuels, including coal, natural gas and oil, are becoming less and less favored due to their environmental disadvantages. The combustion of coal, oil, or gas generates large quantities of carbon dioxide, oxides of sulfur and nitrogen, and other pollutant gases, which may contribute to global warming, acid rain, air pollution and a number of other environmental and health damaging effects. World reserves of oil and natural gas are also thought to be relatively low, and may run out in the foreseeable future. Some credible sources say that the world&#39;s production of petroleum will peak around the year 2008, and will go into a steady decline thereafter. Natural gas is predicted to peak sooner and will take a much more rapid decline than petroleum. Should this be the case, and there is compelling evidence that it is, then alternative sources of energy must be developed immediately to avoid, or delay major world problems.  
      Other sources of energy include nuclear fission, whereby atoms of radioactive elements are bombarded with a neutron source, which splits the radioactive element into an element or elements of smaller atomic mass, generating massive quantities of energy in the process. Unfortunately, the use of radioactive materials means that environmentally safe methods of disposal of waste are difficult to achieve. The radioactive waste generated is commonly stored in sealed containers and then buried in restricted-access landfill sites, caverns under mountains, or dumped at sea. There have been many occurrences of radioactive waste leaking from these containers and damaging the local environment. The damage caused by radioactive waste may be irreversible and the radiation generated by the waste may last for decades.  
      Thus, there is a strong call for non-polluting and renewable energy sources. Known non-polluting and renewable energy resources include photovoltaic cells, tidal-powered electricity generators, hydrogen fueled devices, cold-fusion devices, and wind-powered electricity generators. The wind type of generators generally employ turbine blades extending from a central hub, and which blades are designed to translate the linear motion of wind into rotational motion of the central hub, which is connected to a suitable energy generator. Known generators of this type generally employ turbine blades which are rigidly fixed to the central hub and are orientated such that leading blades are aero-dynamically configured in the optimal position to convert wind linear motion into rotational motion.  
      However, this configuration of fixed blades means that trailing blades are not optimally configured to reduce drag and thus reduces the maximum amount of linear rotational motion available to generators. Thus the optimal conversion of linear to rotational motion may not be achieved using these known systems, and consequently, optimal energy generation is minimal.  
      It is an aim of preferred embodiments of the present invention (VAWTEC) (turbine) to over-come, or mitigate, at least some of the disadvantages of the prior art systems described above, or other disadvantages, whether described above, or not.  
      There are several patents which are similar to this VAWTEC, such as the following: 
          US 2003/0185666 A1     US 2006/0188364 A1     US 2004/0228729 A1        

      These and other patents show devices that can be turned by wind action, but there is no visible method of stopping the turbine should the wind reach a speed that would cause the turbine to self-destruct, or to be stopped for routine maintenance. In addition, there is no means to stop the turbines should the electrical grid be shut down by accident, lightening, transformer malfunction, or other natural causes, or to perform maintenance to the grid. This shortcoming is addressed in this VAWTEC patent, and solved with redundancy.  
     BRIEF SUMMARY OF THE INVENTION  
      This invention (VAWTEC) (turbine) is designed to convert wind energy into alternating current (AC), which is then fed into the public utility company&#39;s (PUC) electrical grid. This VAWTEC does this by employing a vertical column surrounded by radial arm assemblies ( FIG. 1 ). These radial arm assemblies ( FIG. 1 ) contain radial arms ( 11 ), which support two vertically opposed sails ( 15 ). The wind&#39;s forces are exerted against the vertical sails ( 15 ) causing the turbine to rotate.  
      The rotation of the radial arm assemblies ( FIG. 1 ) causes the drive gear ( 22 ) to rotate counter-clockwise (from above), which causes the pinions ( 20 ) on the permanent magnet alternators (PMAs) ( 19 ) to rotate clockwise. The rotation of the PMAs ( 19 ) causes an direct current (DC) to be generated, which is processed by the inverters ( 43 ) into an alternating current (AC). This AC is then fed directly into the PUC grid ( 47 ) through a PUC meter ( 46 ).  
      The rotational speed of the turbine is regulated for two reasons: (1) to avoid self-destruction of the turbine should a windstorm&#39;s velocity exceed a predetermined speed; and (2) to avoid overloading the inverters ( 43 ), causing their catastrophic failure.  
      The central processing unit (CPU) ( 58 ) is located in the control room, and is programmed to store the predetermined maximum RPM of the turbine. Once this maximum speed is reached, the CPU ( 58 ) will read the wind speed from the anemometer ( 57 ) and store this speed in the database. Simultaneously, the stop pins ( 14 ) are lowered by the CPU ( 58 ) causing the sails ( 15 ) to assume a feathered, or neutral orientation to the wind, and the turbine slows to a halt. When the wind speed slows to a point, which is 85% of the maximum allowed RPM, the CPU ( 58 ) will detect this and will send a signal to the stop pin solenoid relay ( 48 ), which feeds a 12-volt signal to the stop pin solenoids ( 13 ). The stop pin solenoids ( 13 ) then raise the stop pin ( 14 ), which then prevents the sails ( 15 ) from rotating 360 degrees. When the sails ( 15 ) engage the stop pin ( 14 ), and after the radial arm assemblies ( FIG. 1 ) reach Point “A” on the drawing, they begin to take on the force of the wind, resulting in the rotation of the turbine.  
      When the RPM of the turbine reaches the point where the maximum capacity of the inverter ( 43 ) is attained, the voltage clamp ( 41 ) will automatically shunt the excess energy into a diverter/dump load ( 42 ), where this excess energy is converted into heat, and is absorbed into the atmosphere.  
      The output of this VAWTEC is converted into an AC energy, which is fed into a PUC meter ( 46 ), which records the amount of energy produced. The PUC pays the owner/owners of the VAWTEC for the use of this energy. PUCs may also own and use these VAWTECs to generate the energy that they provide to the grids around the nation.  
      This VAWTEC is self-orienting into the wind and does not require a vane for orienting the turbine.  
    
    
     FIG.  1   
     Radial Arm Assembly  
      The National Aeronautics and Space Administration (NASA) and the National Oceanic and Atmosheric Administrations (NOAA) have recorded the directions and speeds of the winds at most location around the world. From this data they have developed a mean wind power density class for most reigion of the world. This mean wind power density class is expressed in numbers from 1 to 7, and the wind speed is express in miles per hour (MPH).  
      This VaWTEc is designed to operate at the lower levels, but can also be used at the higher level as well. These Wind Density Classes at 33 feet above ground are:  
                                                   Class   Mean Wind Speed (MPH)                          1     0-9.8           2    9.8-11.5           3   11.5-12.5           4   12.5-13.4           5   13.4-14.3           6   14.3-15.7           7   15.7-21.1                      
 
      One turbine would not effciently suit all of these classes. It is desirable then to design a wind turbine for more than one class say, Class 1 to Class 3 as one model, Class 4 to Class 5 as the second model, and Class 6 to Class 7 as third model. There may also be a need for a turbine to serve the areas where the wind regulary exceeds 21.1 MPH.  
      The only thing is to tailor this turbine for each group is to vary the number of radial arm assemblies ( FIG. 1 ), vary the length of the radial arms ( 11 ), and vary the height and width of the sail ( 15 ). Each of these variations will result in a different torque being applied to the drive gear ( 22 ).  
      The sail ( 15 ) are made of the mast ( 10 ), the boom anchor ( 17 ), the booms ( 16 ), the sails ( 15 ) and assorted fasteners used to hold this assembly together. The sails ( 15 ) can be made from cloth, mental, carbon fiber, or any other suitable material capable of capturing the energy from the wind. The sail journals ( 12 ) contain upper and lower bearings, which keep the masts ( 10 ) vertical, and minimize the friction as the sails ( 15 ) rotate.  
      The wind forces are captured by the sails ( 15 ), which causes the radial arm assemblies ( FIG. 1 ) to rotate counterclockwise (from above) around the vertical axis. In order to cause the sails ( 15 ) to capture the wind&#39;s forces they must be stopped from rotating 360 degrees about their vertical axis by the stop pin ( 14 ). The stop pin ( 14 ) is activated by a continuous-duty solenoid ( 13 ). As the radial alarm assemblies ( FIG. 1 ) reach point “A” on the top view, the sails ( 15 ) are stopped from rotating by the stop pin ( 14 ) and begin to capture the wind&#39;s forces. As the radial arm assemblies ( FIG. 1 ) reach point “B”, they take on the full force of the wind. As the vertical column rotates further, the sails ( 15 ) are exposed to a decreasing amount of the wind&#39;s force.  
      When the radial arm assemblies ( FIG. 1 ) reach point “C” the sails ( 15 ) no longer capture the wind&#39;s force. Shortly after the radial arm assemblies ( FIG. 1 ) pass point “C” the sails ( 15 ) are no longer constrained by the stop pins ( 14 ), and the wind&#39;s force cause the sails ( 15 ) to rotate almost 180 degrees about their axis and become feathered, or neutral to the wind&#39;s force. The reason that the sails ( 15 ) become feathered, or neutral, is because the wind is impinging on both sides of the sails ( 15 ) with an equal amount of force. The sails ( 15 ) will then remain neutral until the radial arm assemblies ( FIG. 1 ) reach point “A” again, and the process is repeated over and over again, which causes the rotation of the VAWTEC. A counterbalance ( 60 ) is provided to counter the centrifugal forces on the sails as they rotate and to smooth out the sail rotation as the radial arm reaches the point “C”, which is 180 degrees from the wind&#39;s direction.  
     FIG.  2   
     Drive Assembly  
      The radial arm assemblies ( FIG. 1 ) are attached to the upper flange assembly ( 18 ), the radial arm mounting plate ( 23 ) and the drive gear ( 22 ) using bolts ( 25 ), bolts ( 27 ) and lock nuts ( 26 ). The torque from the rotation of this drive assembly ( FIG. 2 ) causes the pinions ( 20 ) on the PMAs ( 19 ) to rotate. Rotation of the drive assembly ( FIG. 2 ) causes the PMAs ( 19 ) magnetic rotors to rotate, thereby generating electrical energy. In the typical brush type automotive alternator, 50% of the power generated by the alternator is used in energizing the coil. This is not the case when using PMAs ( 19 ), such as the ones used in this VAWTEC, because the permanent magnets are already permanently charged with a magnetic field.  
      The lower bearing ( 24 ) allows the lower part of the turbine to rotate with minimum friction. The lower bearing ( 24 ) also keeps the upper flange assembly ( 18 ), the drive gear ( 22 ) and the PMA mounting plate ( 28 ) centrally located so as to minimize misfits between these components.  
     FIG.  3   
     PMA Mount Assembly  
      There are a number of PMAs ( 19 ) and a single direct current (DC) starter ( 21 ) clustered around and attached to the PMA mounting plate ( 28 ). The starter ( 21 ) is used to initiate rotation of the radial arm assemblies ( FIG. 1 ) in order to activate the VAWTEC. The number and capacity of the PMAs ( 19 ) used in this VAWTEC will change as the desired maximum output changes and as the technology advances in this area.  
     FIG.  4   
     Crown Assembly  
      The crown assembly ( FIG. 4 ) is located at the top of the turbine. It sits on top of the upper flange assembly ( 32 ) and the upper standpipe assembly ( 18 ). The rotation of the radial arm assemblies ( FIG. 1 ) is caused by the stop pins ( 14 ) preventing the sails ( 15 ) from rotating 360 degrees about their axis by the winds forces. The energy needed to activate the stop pins ( 14 ) is supplied by the stop pin solenoids ( 13 ). The stop pin solenoids ( 13 ) are mounted below the radial arms ( 11 ). The stop pin solenoids ( 13 ) are continuous duty models, and keep the stop pins ( 14 ) in the extended position at all times while the turbine is actively rotating, or down when it is desirable to stop the rotation of the sails.  
      The energy that activates the stop pin solenoids ( 13 ) reaches the radial arms ( 11 ) by traveling through a slip ring ( 33 ), which is located within the crown assembly ( FIG. 4 ).  
      The crown assembly ( FIG. 4 ) also contains the tachometer sensor ( 37 ) and the sensor disk ( 39 ). The sensor ( 37 ) counts the turbine&#39;s revolutions as the magnets in the sensor disk ( 39 ) passes under the sensor ( 37 ). The inner cap ( 31 ) sits on top of the upper standpipe assembly ( 30 ) and positions the upper bearing ( 40 ), which allows the upper part of the turbine to rotate with minimum friction.  
      The upper flange assembly ( 32 ) supports the slip ring assembly ( 33 ). The holes in the outer ring of the upper flange ( 32 ) are used to terminate the cables that are used to support the radial arm assemblies ( FIG. 1 ).  
      The slip ring assembly ( 33 ) allows the energy needed to actuate the stop pin solenoids ( 13 ) to be transmitted from the stop pin relay switch ( 48 ) from the 12-volt power supply ( 56 ). The tachometer sensor ( 37 ) and the terminal block ( 34 ) are mounted on the sensor mounting plate ( 38 ). The sensor mounting plate ( 38 ) is held in place by two snap-rings ( 36 ) on the shaft of the inner cap ( 31 ).  
      The crown assembly ( FIG. 4 ) is protected from the weather by the crown cap ( 35 ).  
      The cable from the tachometer sensor ( 37 ) to the terminal block ( 34 ) and the cable from the slip ring ( 33 ) to the terminal block ( 34 ) terminate at terminal block ( 34 ) for ease of assembly. From there these cables are routed to the control room. These cables are threaded through the center of the inner cap ( 31 ), out the hole in the lower end of the upper standpipe assembly ( 30 ), and continue on to the control room.  
     FIG.  5   
     Electrical Diagram  
      The PMAs ( 19 ) are caused to rotate by the turbine&#39;s rotation, which generates a DC current, which varies according to the RPM of the PMAs ( 19 ).  
      The inverters ( 43 ) have a maximum operating throughput wattage as specified by the manufacturer. In order to prevent excess energy from the PMAs ( 19 ) damaging the inverter ( 43 ), voltage clamps ( 41 ) are employed to divert excess energy to diversion/dump loads ( 42 ).  
      All excess energy consumed by the diversion/dump loads ( 42 ) is dissipated into the atmosphere in the form of heat energy.  
      Occasionally the PUC grid ( 47 ) goes down. This may be due of maintenance procedures, because of equipment failure, or natural causes, such as lightning strikes. When this happens, the energy flow from this VAWTEC must be stopped very quickly in order to prevent injury or death to the PUC maintenance crews. This safety feature is assured by the use of only Underwriter&#39;s Laboratory (UL) approved inverters ( 43 ).  
      These inverters ( 43 ) interrupt the flow of energy from the VAWTEC immediately when the inverters ( 43 ) detects the loss of energy in the PUC grid ( 47 ). However, there is still inertia in the turbine as it spins to a stop, due to the mass of the assembly.  
      The spin-down energy developed by the turbine must go somewhere other than the inverters ( 43 ). When this happens, the voltage clamps ( 41 ) immediately sends all of the energy generated by the VAWTEC to the diversion/dump loads ( 42 ). The diversion/dump loads ( 42 ) then expels this heat energy into the atmosphere.  
      Access to the PUC grid ( 47 ) is controlled by the PUC through a lockable disconnect ( 44 ), which is located adjacent to the PUC meter ( 46 ).  
     FIG.  6   
     Control Diagram  
      The control of this VAWTEC is located within the control cabinet within the control room, which should be located at least ten feet from the base of the turbine for safety reasons.  
      Inside the crown assembly ( FIG. 4 ) are the tachometer sensor ( 37 ), and sensor disk ( 39 ). As the turbine rotates, the magnets imbedded within the sensor disk ( 39 ) pass under the sensor ( 37 ), causing a pulsed signal to be transmitted via the cable from the sensor ( 37 ) to the terminal block ( 34 ). From the terminal block ( 34 ), the signal goes to the central processing unit (CPU) ( 58 ) in the control room. A signal is also transmitted from the anemometer ( 57 ) to the central processing unit (CPU) ( 58 ), where the speed of the wind is detected.  
      The anemometer ( 57 ) is located on top of the anemometer pole, which is located within about 15 feet from the base of the turbine. The wind speed is measured by the anemometer ( 57 ) and transmitted to the CPU ( 58 ) via the cable from the anemometer.  
      The battery ( 29 ) is kept charged by the battery charger ( 52 ), which gets its energy from the PUC grid ( 47 ). There is a manual switch ( 53 ) between the battery charger ( 52 ) and the PUC grid ( 47 ), so as to allow maintenance to the battery ( 29 ), or the battery charger ( 52 ).  
      The battery ( 29 ) provides a 12-volt signal to the relay switch ( 51 ), which energizes the starter solenoid ( 49 ).  
      The 120-V./12-V. inverter ( 54 ) supplies energy to the CPU ( 58 ) through the emergency stop button ( 55 ).  
      Should an emergency occur, the VAWTEC can be stopped manually by pressing the emergency stop button ( 55 ), which is located on the face of the control room.  
      The CPU ( 58 ) is constantly active and gets its power from the 12-V./120V. inverter ( 54 ). At initial startup the VAWTEC is activated by the starter switch ( 50 ), which sends a signal to the starter solenoid ( 49 ). The starter switch is activated causing the pinion on the starter ( 20 ) to engage the drive gear ( 22 ) and make it rotate in the counterclockwise direction (from above).  
      Once the turbine begins to rotate, the sails ( 15 ) begin taking on forces from the wind, and will continue to rotate the turbine as long as the wind is blowing. If the wind stops blowing the turbine will slow to a stop. Once the wind starts blowing again the turbine will start rotating again, because the stop pins ( 14 ) are always in the up position, unless the system is stopped by the emergency stop button ( 55 ), or the PUC grid ( 47 ) loses energy.  
      When an unusually strong wind comes along, such as a tornado, or a hurricane, the turbine will increase in RPM until the design limit RPM is reached. The design limit RPM is stored in the CPU ( 58 ). Once the design limit RPM of the turbine is reached, the CPU ( 58 ) will automatically shut down the turbine. Just prior to shutting the turbine down the CPU ( 58 ) captures the RPM from the tachometer sensor ( 37 ), and at the same time captures the wind speed from the anemometer ( 57 ). The CPU ( 58 ) will record this wind speed as the system&#39;s design-limit wind speed. Once the wind speed drops to a point which is 85% of the maximum design-limit wind speed, the CPU ( 58 ) will restart the turbine by sending a 3-5-second long signal to the starter relay switch ( 51 ), and to the starter solenoid ( 49 ). The stop pins ( 14 ) will be raised to the upper position, and the sails ( 15 ) will engage the stop pins ( 14 ). Then the starter ( 21 ) will cause the turbine to start rotating, it will become active, and will once again begin generating energy for the PUC grid ( 47 ). This VAWTEC can also be used to charge storage batteries should the user decide to generate electricity to a residence, or some other facility.  
      It should be understood that the forgoing relates to exemplary embodiments of the invention and that modifications may be made without departing from the spirit and scope of the invention as set forth in the following claims: