Abstract:
A cellular communication tower is adapted to support a vertical axis wind turbine (VAWT) that includes a generator mechanism. The signal and power cable for the communication antennas run through the central axis or bore of the generator. The blades of the VAWT are disposed so as to avoid interferences with communication signals. The tower preferably deploys an open truss construction to avoid the impact of periodic pressure pulse as the turning blades shift out of alignment from shading the tower. Thus, with an open truss tower the turbine blades can be a larger size and still not cause such pressure pulses.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present application claims the benefit of priority to the U.S. provisional application of the same title having application Ser. No. 61/287,635, which was filed on Dec. 17, 2009, which is incorporated herein by reference. 
    
    
     BACKGROUND OF INVENTION 
     The present invention relates to the provision of energy to wireless telecommunications systems, and in particular to such provision by wind powered generators, as well as to the generation of electrical power from wind energy. 
     Wireless telecommunications technology is especially attractive to remote communities lacking an existing signal wire system, and in particular to developing countries that have no or minimal telecommunications outside of major cities. 
     However, while cellular wireless telecommunication is well advanced, the locations most lacking in these services also frequently lack connection to a reliable electrical power distribution infrastructure to provide power to the electronic systems, such as the radio frequency and microwave transceivers, deployed on cellular telecommunication transmission towers. 
     It is therefore a first object of the present invention to provide a means for powering the electronics systems deployed on remote cellular telecommunication transmission towers as well as provide a reliable power source for remote cell communication towers 
     It is a further object of the invention to reduce the installed cost of generating electrical power by taking advantage of telecommunication infrastructure. 
     SUMMARY OF INVENTION 
     In the present invention, the first object is achieved by providing a tower structure comprising, a substantially vertical support tower having a top portion and a lower mounting base and at least a portion with a central vertical lumen or opening therein between the top portion and the lower mounting base thereof, a vertically arrayed wind turbine (VAWT), having a central mounting hub and a plurality of turbine blades coupled thereto to provide free rotation about the central opening of said substantially vertical support tower, an electrical generator rotationally coupled to said central mounting hub, at least one of a receiver, transmitter or transceiver of electromagnetic radiation supported by said a substantially vertical support tower and disposed above said VAWT, at least one cable for power transmission extending downward from the generator, being electrically coupled thereto to the lower mounting base, and at least one cable extending upward from the lower mounting base through the central mounting hub of the VAWT to connect in signal communication with said at least one of an receiver, transmitter or transceiver. 
     The above and other objects, effects, features, and advantages of the present invention will become more apparent from the following description of the embodiments thereof taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a perspective view of a first embodiment of the invention. 
         FIG. 2  is a perspective view of a second embodiment of the invention. 
         FIG. 3  is a perspective view of a second embodiment of the invention. 
         FIGS. 4A  and B is a plan view of section A-A of  FIG. 1  illustrating alternative positions of the antenna blades 
         FIG. 5  is cross-section elevation of a portion of the embodiment shown in  FIG. 1-3 . 
         FIG. 6  is cross-section elevation of a third embodiment of the invention. 
         FIG. 7  is cross-section elevation of a fourth embodiment of the invention. 
         FIG. 8A  is a plan section view of a portion of the tower and generator/alternator showing a preferred method of assembly, whereas  FIG. 8B  is a cross-sectional elevation thereof. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1 through 8 , wherein like reference numerals refer to like components in the various views, there is illustrated therein a new and improved antenna mounted wind power generator, generally denominated  100  herein. 
     In accordance with the present invention,  FIG. 1  illustrates a first embodiment of the antenna mounted wind power generator  100  that comprises an antenna assembly  105 , consisting of generally conventional antenna devices, in this case panel type transceivers  140  of electromagnetic radiation that transmit and receive encoded RF or microwave signal information. This antenna assembly  105  is mounted at the top of the antenna support tower  110  and disposed above the vertically arrayed wind turbine (VAWT)  120 . In this embodiment the antenna support tower  110  is a tubular tower, having a generally circular cross-section. At least a portion of the antenna support tower  110  below the antenna assembly  105  has a lumen or central vertical opening  111 , although it appears solid on the outside. The VAWT  120  is mounted on the antenna support tower  110  below the antenna assembly  105 , being disposed for free rotation about the central opening  111  via at least one pairs of two hubs  121  and  121 ′ that are coupled to the antenna support tower  110 . Since this particular VAWT  120  has a pair of coupled blade assemblies  125  and  126  stacked on each other there are 2 hubs,  121  being disposed at the top of the upper blade assembly  125  and  121 ′ being disposed at the bottom of the lower blade assembly  126 . Radial struts  124  extend outward from each hub  121  and connect to horizontally disposed blade support rings  122 ,  122 ′ and  122 ″′. The blades  123  are vertically disposed and connect to each blade assembly  125  and  126  by the blade support rings  122  and  122 ′ or  122 ′ and  122 ″, at their top and bottom Thus, each of the blade assemblies  125  and  126  has in common the centrally disposed of the three blade support rings  122 ′, which is not connected to the antenna support tower  105  directly. The generator  130  is preferably disposed below hub  121  so that its rotor  132  can be connected to the rotating outer portion of the lower hub  121  that is driven by wind induced rotation of the rings supports  122  by the force acting on the turbine blades  123 . A preferred VWAT architecture is described in US Pat. Appl. no. US 2008/0253889 A1, of Krivcov et al. that published on Oct. 16, 2008 for a VERTICAL AXIS WIND TURBINES, which is incorporated herein by reference. 
     Alternative designs for VWAT are also disclosed in U.S. Pat. No. 7,329,965 B2 issued to Roberts et al. on Feb. 12, 2008 for an AERODYNAMIC-HYBRID VERTICAL-AXIS WIND TURBINE, which is also incorporated herein by reference. It is not intended that the invention be limited to any particular form of a VAWT. 
     As the portion of the tower  110  that support the VAWT  120  cannot interfere with the hub rotation, the signal cables  160  that connects a base station  520  to the RF or microwave transceiver  140  runs through the lumen or central vertical opening  111 , as shown in  FIG. 5 . The power cable(s)  150  emanate from the generator  130  can run down either the outside of the tower  110  or through the portion of the central opening  111  that extends below the vertical expanse of the VAWT  120 . 
     Generally speaking VAWT&#39;s have particular advantages as compared to deploying horizontal axis wind turbines. This is particularly true for the inventive combination with the antenna system  105  at the top of the tower. The VWAT blades  123 , being oriented in the same direction of the tower  110  are below the antenna  140  and will not shadow or block them in a manner that would attenuate signals. 
     Further, because the centers of gravity of the VWAT  120  and generator  130  align are both disposed on the central or primary vertical axis of the on the antenna tower  110 , the structural demands of the antenna tower  110  are not expected to be significantly greater than they would be for just the antenna assembly  105 . As a mounting tower is a significant part of the cost of any wind turbine system, using cellular telephone transmission towers reduces the cost to supply electrical power with a wind turbine, which can power the antenna or serve other users in the area. 
     Further as the preferred embodiment of the VWAT is efficient at generating power in light winds from any direction, the antenna mounted wind generator system is practical and useful to deploy in most locations where the antennas would be sited for communication purposes only. The ability to generate power in light winds from any direction favors using the VWAT generated power to energize the antenna system itself as described further below, as it is more likely that power will be available when needed. However, to the extent there is not always the minimum wind necessary to generate power, back up batteries, or any other energy storage medium for such occasions could at least be of are reduced size to accommodate the rare occasions where there would not be sufficient wind to turn the VWAT. 
     Further, as VWAT&#39;s  120  have lower tip speed of the turbine blades that rotate in a vertical plane about a horizontal shaft they tend to minimize the potential for bird kill. 
     In the embodiment shown in  FIG. 1 , the antenna support tower  110  is an elongated tube of generally circular cross-structure. 
     In the embodiment shown in  FIG. 2  the antenna support tower  110  has an open truss framed tower from the ground until the antenna portion  105 . 
     In the embodiment shown in  FIG. 3  the antenna support tower  110  is an elongated tube of generally circular cross-structure in the lower portion  110   a  between the ground and the generator  130 , which is situated just below hub  121  to couple to the rotor  132  ( FIG. 5 ). However, the central portion  110   b  of the tower  110  that runs through the VWAT  120  is of a truss type framed construction. One non-limiting example of such a frame construction is illustrated as composed of vertically spaced apart rings held at their outer periphery by a plurality of vertical posts. 
       FIGS. 4A and 4B  illustrate why the embodiment of  FIG. 2  is more preferred over that in  FIG. 1 . In these figures the wind is coming from the left as indicated by the array of arrows  200 . Each turbine blade  123  creates a lower pressure “shadow”  210  in the region behind it with respect to the wind direction and blade shape. In  FIG. 4A , the shadows  210  do not cross the cross-section of the antenna tower inside hub  121 , hence the antenna is subjected to the force of the wind  200 . However, in  FIG. 4B , as the blades  123  have rotated with support ring  122 , a blade now casts a lower pressure “shadow” that includes the tower  110 . Thus, with a solid tower, due to its wider cross-section, will be subject to a periodic variation in stress as the VWAT rotates, coming in and out of the shadow  210 . However, if the section of the tower  110   b  within the central axis of the VWAT&#39;s rotation is generally open constructed from struts, rings or trusses, the pressure variation will be lower although the same “shading” will still occur, as the such constructions present a much small cross-section when not “shaded” in  FIG. 4A . 
     Thus,  FIG. 2  and  FIG. 3  are more preferred embodiments because they minimize such periodic stress and potential for movement to the antenna  105 . Where a solid tower cross-section is preferred at a least the ground level, the embodiment of  FIG. 3  is more preferred as the strut or frame is only visible far from the ground away for the height of the VWAT  120 . 
       FIG. 5  illustrates in more detail an embodiment for coupling the rotating portion of the hub  121 , to the stator  131  of generator  130 . The hub  121  that supports the VWAT blades  123  is connected in rotary engagement with the tower  110  by the bearing plate  501 .  FIG. 5  also illustrates an additional embodiment in which the power generated by the VWAT, via generator  130 , is transmitted via cable  150  to a battery  510 . The battery  510  optionally powers the base electronic system or unit  520  that is connected to the signal cable  160 . The signal cables  160  convey signal and routing information to the base electronic system for routing to different antennas or land based telecommunication cables. The base electronic signal system need not be located at ground level, and it components can be disturbed in different location with respect to the antenna assembly  105 . Thus, antennas or transceivers  140  are optionally self-powered by the VWAT  120 , or powered by the VWAT  120  via a battery  510 , when either normal (land base power) or wind power is not available due to insufficient breezes. 
     It should be appreciated that the various embodiment described above have the benefits of reducing the installed cost of generating electrical power by taking advantage of telecommunication infrastructure, that is the necessity of having erected plural remote towers for cellular phone communications. Thus the power generated by VWAT  120  can be used by local users or feed back into the power grid. 
     VWAT&#39;s of the preferred design has several advantages for recharging the batteries of a cell phone base station, or generating electricity in general. As the cell phone towers are likely to be situated by reception criteria, and not specifically to take advantage of locations with steady high wind conditions, the VWAT design is particularly advantageous because it is self starting in low wind conditions. Further, the performance of the VWAT does not depend on the wind direction, in that is omni-directional. Not only does the generator&#39;s  130  electrical output not depend on the compass heading of the wind, it also doesn&#39;t matter how rapidly it changes direction. Thus, the preferred VWAT turbine still captures wind energy as the wind changes direction, which that is continuously converted to electrical power. Further, the VAWT mass acts as a flywheel, picking up some speed in wind gusts and continuing to rotate in the short periods of low wind. Accordingly, a VWAT of the preferred design can be constantly charging the back-up battery or generating power in a wider range of cell tower location. Unlike Horizontal Axis Wind Turbine (HAWT), there is no requirement for the windmill to “seek” the wind direction. Accordingly another advantage of the invention is the elimination of the expensive and unreliable mechanics related to pointing an HWAT toward the wind. Thus, a VWAT will have a smooth, steady, quiet motion eliminating noise, and reducing energy losses of starting and stopping. Vibrations in the mounting structure are also reduced, while the flywheel effect gives a more constant voltage output to the electronics. Accordingly, the various embodiment of the invention will provide a reliable power source for remote cell communication towers and other users or consumers of power. 
     It is also expected that the preferred embodiments will not cause interference with RF transmission, as well as provide for easier maintenance to the generator, such as replacing bearings, without the need to depower or terminate RF transmission. 
     In furtherance of another objective of facilitating maintenance of the RF transmission system  105 ,  FIG. 6  illustrates a more preferred embodiment in which a tower  110  is hollow and can be entered at or near the ground  1  via a lower access door  601  via portal  611  that allows maintenance personnel  10  to enter and climb up the internal ladder  602 , exiting an upper access door  603  at portal  613 , thus leading them to the panel type transceivers  140  and connecting signal cables  160  that also runs through tower  110 . The ladder  602  can be a series of spaced apart vertical rungs, without the connecting extending horizontal side bars, or any other structure or apparatus that permits self propelled or automated transportation of the maintenance personnel  10  above the VWAT  120  to access the antenna supporting portion of the tower. As shown in this figure, it may be preferable that the tower  120  is a hollow tube below upper access door  603 , but of strut or truss construction above it. 
       FIG. 7  illustrates an alternative and more preferred embodiment in which the tower  110  is solid but internally hollow to provide access via the internal ladder  602  as in  FIG. 6 , however, the exit portal  613  and upper access door  603  are now located below the VWAT  120 , in the lower portion  110   a , such that the upper portion  110   c  of the tower  110  below the antenna system  105 , including the panel type transceivers  140 , is of a hollow strut or truss construction structure through which the ladder  602  optionally extends providing access to transceivers  140  while the VWAT  120  rotates. Depending on the strut or truss spacing the ladder need not be a continuous unitary structure, but can be additional foot and handhold members spaced apart the conventional distance of about a foot (about 30 cm), which may include some strut or truss members themselves. 
       FIG. 8A  schematically illustrates in a plan view of a preferred embodiment in which portions of the generator are assembled from arc shaped segments that surround the hollow tower  110 .  FIG. 8B  is a cross-sectional elevation of the same region. The stator  131  is formed from a plurality of arc shaped stator segments  8131  that are attached to a flange or hub  121 ′ that is coupled to the tower  110  to provide the stationary portion of the generator  130 . The rotor  132  is formed from a plurality of arc shaped rotor segments  8132  that are attached to a flange or hub  121  that is coupled to tower  110  by rotary bearings to form one or more rotor assemblies  131 . One or within each rotor segment  8132  are a plurality of wedge shaped magnets  8032  that alternatively in polarity to provide along with the stator  131 , an axial gap electric dynamo type generator/alternator. In the more preferred embodiment of  FIG. 8B , each arc shaped segment  8131  that will form the stator disc  131  has connected serpentine wiring  8031  loops on both sides and is inserted sideways over the rotor disc  132 . The serpentine winding in such a disc is disclosed in U.S. Pat. No. 7,646,132 B2, issued to R. Halstead on Jan. 12, 2010, which is incorporated herein by reference. It should also be appreciated that such arc shaped rotor and stator segment can be pre-assembled into arc shaped units which are then mounted on the appropriate hub structure on the periphery of the tower  110 . Further, one the arc shaped segment of the rotor and stator are coupled to the tower via a hub they can be mechanically coupled to each other for greater stability. 
     It is also preferred that a magnetic bearing be deployed at the outer extremity or perimeter of the rotor disk  132 , such as that disclosed in the US Pat. Application No. used at the perimeter of the rotor disk  132 , as disclosed in US Patent Publication No. 2009-200883A1, published on Aug. 13, 2009, which is incorporated herein by reference. Such a magnetic bearing assembly can also be assembled in arc shaped segment as described above. 
     While the invention has been described in connection with a preferred embodiment, it is not intended to limit the scope of the invention to the particular form set forth, but on the contrary, it is intended to cover such alternatives, modifications, and equivalents as may be within the spirit and scope of the invention as defined by the appended claims. 
     For example, the VAWT  120  of antenna assembly  100  may deploy additional pairs of stacked coupled blade assemblies than the two ( 125  and  126 ) shown in  FIG. 1-3 , as for example 3 to 4 blade assemblies. In addition, more than 3 individual blades or air foils  123  can be deployed in the 2 or more blades assemblies, as for example 3-5 blades per stacked blade assembly. This would provide more power pulses per revolution at the same periodicity provided there is a symmetrical offsetting or staggering of the blades  123  on each tier or blade assembly. In the example in which the VWAT deployed 3 tiers or stacked coupled blade assemblies and 3 blades  123  are deployed on each tier, the first blade  123  would have an absolute angular references about the tower axis of zero degrees, with the other 2 blades on the same tier would be set at 120 and 240 degrees (for a spacing of 360/number of blades). Whereas on the upper or second tier the blades would at an angular reference position or offset of 40, 160 and 280 degrees, as well as an angular offset on 80, 200 and 220 degrees on the third tier of blades. Note that the annular offset between each tier is the spacing within the tier (120 degrees), divided by the number of tiers. It should now be appreciated that other variations of spacing and different numbers of tiers are both possible and practical.