Patent Abstract:
Disclosed is a method of supplying DC power to equipment using proton exchange membranes (PEMs). PEMs run on hydrogen to produce DC electrical power. In the disclosed embodiment these PEMs are used as an alternative source of power to AC sources. One of these other sources is generated by an array of gas turbines. Another source is provided by a commercial utility. AC from these sources is converted using rectifiers. Capacitors are used to bridge when switching between energy sources.

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation of and claims priority pursuant to 35 U.S.C. Section 120 from U.S. patent application Ser. No. 10/886,345 filed Jul. 7, 2004 now U.S. Pat. No. 6,879,052 which is a divisional of U.S. patent application Ser. No. 10/298,074 filed Nov. 15, 2002. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   Not applicable. 
   BACKGROUND OF THE INVENTION 
   In general, this invention relates to a system for providing electrical power. More specifically, this invention is directed to a system particularly adapted to provide reliable electrical power for the operation of a remote telecommunications facility. 
   Although it may be utilized in numerous applications, this invention is specifically adapted to provide power for the continuous operation of a remote telecommunications facility. With its core technology substantially composed of digital components, the telecommunications industry is heavily dependent on the continued supply of reliable electrical power. The critical nature of the functions performed by remote telecommunications facilities further emphasizes the need for a dependable power supply. 
   Most telecommunications facilities rely on a commercial power utility for electrical power and employ traditional devices, such as a transformer and switchgear, to safely receive and use the electrical power. To insure the facility&#39;s power supply is not interrupted, such as in the case of a black-out or other disturbance in the commercial power system, many telecommunications facilities have a system for providing backup power. Although various designs are used, many backup systems employ a diesel generator and an array of batteries. If power from the commercial utility is lost, the diesel generator takes over to supply power, and the battery array insures that power is maintained during the time it takes to switch from utility-supplied power to generator-supplied power. If the generator also fails, such as due to a mechanical malfunction or to the depletion of its fuel source, then the battery array is able to provide power for an additional period of time. 
   There are several disadvantages inherent in the current manner in which power is supplied to telecommunications facilities. First, the cost of local electrical utility service has risen dramatically in recent years and, by all accounts, will continue to rise. Thus, the cost of local electrical utility power is a large component of the facility&#39;s overall power expenses. Next, as the facility&#39;s power demands have increased, the number of batteries required to provide an adequate amount of power for a reasonable period of time has also increased. Clearly, the component cost of the system increases with the greater number of batteries required. In addition, the greater number of batteries required has significantly increased the space required to house the backup system, which has increased the spacial cost of the systems. Finally, it is known that generators suffer from certain reliability problems, such as failing to start when needed because of disuse or failed maintenance. Therefore, the reliability of the backup systems could be improved. 
   The power system of the present invention overcomes these disadvantages by providing reliable electrical power that is not initially dependent on a commercial electrical utility and that does not employ an array of batteries. The system, therefore, is more cost efficient and requires less space than the present manner of providing power to facilities. The invention employs redundant sources of power, and thus, is uninterruptible. Also, the system employs power generating components that have less of an impact on the environment than the current manner in which power is supplied. Moreover, the system may be constructed at a manufacturing site and then moved to the facility. Thus, the system of the present invention provides power to a telecommunications facility in a manner that is less expensive, that requires less space, that is movable, and that is environmentally friendly. 
   BRIEF SUMMARY OF THE INVENTION 
   The present invention includes a power system that is designed to provide reliable electrical power to a facility, and specifically to a telecommunications facility. The system includes a number of microturbine generators adapted to provide AC power. The system is configured so that the microturbine generators are fueled initially by natural gas supplied by a commercial utility. In the event the natural gas supply fails, the system includes a propane storage tank to provide fuel to the microturbine generators. The system also has an array of rectifiers to convert the AC power from the microturbine generator to DC power. If both of the microturbine generators&#39; fuel sources fail or become exhausted, power is supplied to the rectifiers by a commercial electrical utility, and the system includes components to receive the utility-supplied electricity. The system also includes a number of hydrogen-powered proton exchange membranes that are operable to supply DC power directly to the facility if both the microturbine generators and the electrical utility fail. Finally, the system includes a number of super capacitors that are operable to maintain power during the time required to change between power sources. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The present invention is described in detail below with reference to the attached figure, wherein: 
       FIG. 1  is a schematic diagram of the present invention without the sensing/control mechanism. 
       FIG. 2  is a functional block diagram of the major components of the present invention; and 
       FIG. 3  is a block diagram showing the physical relationship of the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   The present invention includes both a system and a method for providing reliable electrical power to a facility, and specifically to a telecommunications facility. The system provides redundant sources of electrical power including a number of microturbine generators and a number of proton exchange membranes (PEMs). The system also includes a number of capacitors to provide power during the time it takes to switch between power sources. By employing these components, the system avoids the need for an array of batteries and is more cost efficient than the current method for providing power to telecommunications facilities. 
   The present invention is best understood in connection with the schematic diagram of  FIGS. 1–3 . In  FIG. 1 , the power system of the present invention initially comprises a number of microturbine generators  10 . A turbine includes a rotary engine actuated by the reaction or impulse or both of a current of fluid, such as air or steam, subject to pressure and an electrical generator that utilizes the rotation of the engine to produce electrical power. Microturbine generators are a recently developed technology and have not been employed to provide power to a telecommunications facility. A microturbine is smaller and more compact than more common turbines and creates a lower amount of harmful emissions than both more common turbines and diesel generators. A microturbine generator includes a system for receiving fuel, a microturbine for converting the fuel received to electrical power and a digital power controller. Thus, a microturbine generator is able to utilize a fuel source such as natural gas or propane to produce electrical power. One microturbine generator that is suitable for the present invention is the Capstone 60 MicroTurbine™ system produced by the Capstone Turbine Corporation of Chatsworth, Calif. As is understood by those in the art, the number of microturbine generators used in the inventive system depends on the amount of power required by the destination facility. 
   The present invention is designed to provide fuel from two different sources to microturbine generators  10 . Initially, microturbine generators  10  are fueled by natural gas. The natural gas is received in primary fuel valve  20  which is coupled to primary fuel pipe or line  30 . Pipe  30  is also coupled to a series of valves  40 , and each of valves  40  is also coupled to an input of a corresponding mixing box  50 . The output of mixing boxes  50  is coupled to the input of one of microturbine generators  10 . Microturbine generators  10  may also be powered by propane stored in a local storage tank  60 . The propane is received through backup fuel valve  70  which is coupled to backup fuel pipe or line  80 . Pipe  80  is also coupled to a series of valves  90 , and each of valves  90  is coupled to an input of mixing boxes  50 . Mixing boxes  50  is operable to combine fuel received with any necessary additional components and thereafter provide appropriate amounts of fuel to microturbine generators  10 . Mixing boxes  50  are capable of receiving and responding to a control signal by at least opening or closing lines. In addition, valves  20 ,  40 ,  70  and  90  are also capable of receiving and responding to a control signal by at least opening and closing. 
   Microturbine generators  10  utilize the natural gas or propane fuel to produce AC electrical power. The output electrical current from each microturbine generator  10  is coupled to one end of a circuit breaker  100  in order to protect the circuit such as, for example, if microturbine generator  10  causes a power surge. The opposite end of circuit breakers  100  is coupled to a bus line  110  that is also coupled to switch  120 . Bus line  130  is coupled to the output of switch  120  and to a number of rectifiers  140 . As is known, a rectifier is capable of receiving an AC input and rectifying or converting that input to produce a DC output. Thus, rectifiers  140  convert the microturbine-produced AC power to DC power. The output of rectifiers  140  is coupled to bus line  150  which is connected to the power distribution unit  160  in the destination facility. Power distribution unit  160  contains connections into the telecommunications facility&#39;s power lines, and/or provides connections to the various telecommunications equipment. Power distribution unit  160  may also contain additional circuit breakers or other power switch gear or safety devices and/or circuits, including circuits to limit the voltage or current provided to the facility&#39;s power lines, and monitoring/measuring equipment. A number of super capacitors  170  are also connected to bus line  150 . 
   The system of the present invention is also capable of receiving power from a commercial utility. Utility-supplied power is received on bus line  180 , and a connection to ground is provided through line  190 . Bus line  180  is connected to one side of switch  200 , and the other side of switch  200  is coupled to the primary side of transformer  210 . As is known, a transformer is capable of receiving an input signal on its primary side and producing a corresponding signal on its secondary side that is electronically isolated from the input signal. The secondary side of transformer  210  is coupled to one side of a main circuit breaker  220 . The opposite side of main circuit breaker  220  is coupled to one side of a number of circuit breakers  230 . The opposite side of one of the circuit breakers  230  is connected to bus line  240 ; the remaining circuit breakers  230  are available to provide electrical power for additional applications or systems. Bus line  240  is also connected to an input of switch  120 . 
   The power system of the present invention also includes a number of proton exchange membrane fuel cell modules (PEMs)  250 . A PEM is a device that is capable of converting dry gaseous hydrogen fuel and oxygen in a non-combustive electrochemical reaction to generate DC electrical power. Because the only by-products of this reaction are heat and water, a PEM is friendly to the environment and may be used indoors and in other locations where it is not possible to use a conventional internal combustion engine. In addition, unlike a battery, a PEM is capable of providing electrical power for as long as fuel is supplied to the unit. One PEM that is suitable for the present invention is the Nexa™ power module manufactured by Ballard Power Systems Inc. of Burnaby, British Columbia, Canada. As with microturbine generators  10 , the number of PEMs  250  required is dependent on the amount of power required by the destination facility. 
   Hydrogen fuel is supplied to the PEMs  250  from a number of storage tanks  260  located in a vault  270 . Each of the storage tanks  260  is coupled to a valve  280 . Each of valves  280  is coupled to a valve  290  which is also coupled to a pipe  300 . Thereafter, pipe  300  is coupled to a series of valves  310 , and each of valves  310  is coupled to one of the PEMs  250 . The output of the PEMs  250  is connected between bus line  150  and a circuit breaker  320 . As stated above, super capacitors  170  and the power distribution unit  160  of the facility are also connected to bus line  150 . The other side of circuit breakers  320  is connected to a bus line  330 . There are two switches connected to bus line  330 . Switch  340  is coupled to bus line  330  on one side and bus line  150  on the other side. Switch  350  is coupled to bus line  330  on one side and bus line  360  on the other side. Unlike bus line  150 , bus line  360  is only connected to power distribution unit  160  of the facility. 
   The power system of the present invention also comprises a number of sensing and control mechanisms (not expressly shown) for determining which fuel source to activate and which power source to engage. As is known, the sensing mechanisms may be separate devices or may be integral to the valves, bus lines, and/or devices being monitored. Likewise, the control mechanism may be a separate device, such as a programmable logic controller, or may be part of one of the components already described, such as the microturbine generators  10 . It is also possible that the sensing and control mechanisms may be combined into a solitary mechanism that may be a stand-alone unit or may be combined with one of the components already described. 
   The operation of the power system may be understood by referring to  FIG. 2 . It should be noted that the present invention is represented in  FIG. 2  by functional blocks. Thus, sensing/control mechanism  370  is shown as one unit when in fact the sensing and control devices actually may be several devices as discussed previously. Of course, all of the sensing and control devices actually may be placed together in a separate unit, such as a programmable logic controller, as shown in  FIG. 2 . 
   In operation, the sensing/control mechanism  370  initially causes valves  380  (which include valves  40  and  90  shown in  FIG. 1 ) to allow natural gas to flow from the utility source to the microturbine generators  390  and to prevent the flow of propane to microturbine generators  390 . Sensing/control mechanism  370  also initiates operation of the microturbine generators  390 . In addition, sensing/control mechanism  370  also causes valves  400  (which include valves  310  shown in  FIG. 1 ) to prevent the flow of hydrogen to the PEMs  410  and causes the PEMs  410  to remain off. In this manner, microturbine generators  390  produce AC power using utility-supplied natural gas. The AC current produced by the microturbine generators passes through switch  420  to rectifiers  430  where it is converted to DC current. Thereafter, the DC current from rectifiers  430  is provided to the telecommunications facility and to super capacitors  440 . As is well known, when they first receive DC current, super capacitors  440  charge to the level of the DC power provided. 
   If sensing/control mechanism  370  determines that there is an interruption in the utility-supplied natural gas, then it will cause valves  380  to prevent the flow of natural gas and allow the flow of hydrogen to microturbine generators  390 . Switch  420  remains in the same position as before and valves  400  continue to prevent the flow of hydrogen to PEMs  410 . In this configuration, microturbine generators  390  continue to generate AC power but now their fuel is propane. 
   If the sensing/control mechanism  370  determines that both fuel sources for microturbine generators  390  have failed or that there is some other disturbance in the microturbine-supplied power which causes that power to become inadequate, then sensing/control mechanism  370  will cause valves  380  to close and deactivate the microturbine generators  390 . Sensing/control mechanism  370  will set switch  420  so that rectifiers  430  receive AC power from the electric utility. In addition, sensing/control mechanism  370  will keep valves  400  closed and PEMs  410  deactivated. 
   If sensing/control mechanism  370  determines that the electric utility has failed or the power it supplies has become inadequate and the microturbine generators  390  remain deactivated, such as due to a lack of fuel or a malfunction, then sensing/control mechanism  370  will cause valves  400  to open which allows hydrogen to flow to PEMs  410 . Thereafter, the control mechanism will activate PEMs  410 . In this manner the PEMs  410  provides DC power to the telecommunications facility and to super capacitors  440 . 
   In each of the above scenarios, super capacitors  440  provide electrical power during the time it takes for the control mechanism to switch from one power source to another. Thus, super capacitor  440  must have a discharge time greater than the longest time required to switch between power sources. One super capacitor that is suitable for this invention is manufactured by Maxwell Technologies located in San Diego, Calif. 
   Referring now to  FIG. 3 , significant portions of the present invention may be enclosed in a modular, weatherproof container, indicated by the numeral  450 , that is transportable by truck or rail. For example, all of the components shown in  FIG. 1 , except tank  60  and vault  270  with the components contained therein, may be pre-assembled and pre-wired with the sensing/control mechanism(s) and then placed in container  450  before being shipped to a facility. Once at the facility, propane storage tank  460  and hydrogen storage vault  470  are provided and coupled to container  450 . Once utility-supplied natural gas and electricity lines have been coupled to container  450  and the output of container  450  is coupled to the telecommunications facility  480 , then the unit may be activated. 
   As discussed, the power system described above initially employs microturbine generators to provide electrical power for a telecommunications facility. The microturbine generators are compact, efficient (both in terms of space and fuel) and reliable. By relying on microturbine generators as the main source of power, the system avoids both the reliability problems and environmental hazards inherent in internal combustion generators and the costs and environmental concerns associated with commercial electrical power. The power system also provides redundant sources of power, specifically from a commercial electrical utility and a number of proton exchange membranes, and therefore is uninterruptible. Finally, the system provides a number of super capacitors to provide electrical power during the time it takes to switch between power sources. By employing super capacitors and proton exchange membranes, the power system avoids the use of batteries thereby saving significant cost and space. 
   It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, all matter shown in the accompanying drawings or described hereinabove is to be interpreted as illustrative and not limiting. Accordingly, the scope of the present invention is defined by the appended claims rather than the foregoing description.

Technology Classification (CPC): 8