Abstract:
One embodiment of this invention includes a source sharing circuit that is coupled to a power machine. Examples of the power machine include micro-turbine generators, gasoline engine powered generators, fuel cells, and Stirling engines. The power machine is placed in a users home as an alternate source of power. The source sharing circuitry may be coupled to a local load, the power grid and to a digital communications link. The source sharing circuitry is capable of actuation the power machine based upon a variety of factors. Additionally, the digital communications link is capable of two-way communications and transmission of many forms of data, including programs, video, audio, telephone calls and the like. Accordingly, telephones, televisions, appliances and computers may use the source sharing circuitry as a central data gateway from which to receive data from telephone networks, television and radio networks, the internet and the like.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation in part of non-provisional patent application Ser. No. 09/594,111, filed Jun. 14, 2000, the disclosures of which, including all attached documents and appendices, are incorporated by reference in their entirety for all purposes. 
    
    
     TECHNICAL FIELD 
     This invention relates generally to data networking systems and, more specifically, to data communication systems for use with distributed generation networks. 
     BACKGROUND 
     Providing information delivery infrastructure, i.e. “networking”, is rapidly becoming big business throughout the world. Some estimates project the networking business to grow to $2.3 billion dollars annually by the year 2003. Many players, including cable television infrastructure companies, telephone and cellular telephone infrastructure companies and even electric utilities, are rapidly entering the networking market. A common business strategy is to offer a variety of bundled services to consumers, including television, radio, telephone, internet access, home shopping, home security, and remote medical monitoring services. While there is no standard communication infrastructure, examples of some in use today include telephone lines, electric power lines, fiber optics, ethernet networks, wireless communication, infrared communication links, lasers, satellites and coaxial cables. Cable television companies are trying to become telephone service providers, while telephone companies are trying to provide cable television service. 
     In parallel with this growth in networking, electric utilities are becoming deregulated. Whereas a single company used to generate, transmit, distribute and market electricity, these “legacy utilities” are being broken into generation companies, transmission and distribution companies and energy marketers. As of summer 2000, public utilities in over one half of the states have experienced deregulation. Consequently, some electric utilities are beginning to diversify by offering “energy management services” in addition to raw electric energy. These services may include prepaid energy, the ability to turn on and off appliances in the home from a remote location, and some basic data transfer options through power lines. As deregulation threatens to trim profit margins, utilities want to offer new services to customers to add both value and revenue. 
     All three entities, telephone companies, cable companies, and utilities have difficult challenges to overcome to be high volume networking companies. Telephone companies, are limited by speed and bandwidth. When telephones were first designed, the engineers know that when people talked, the pauses between words were often longer than the words themselves. Thus, physical telephone lines were designed to “switch” to lines where people were talking while others were pausing. Thus, there is a finite capacity of physical “connectibility” for phones. When computer modems came about, computers needed a direct connection and modems thus generated a base tone to keep the phone network from switching. As a consequence, the phone lines could not switch and the finite capacity became even smaller. Fully twenty-five percent of today&#39;s telephone infrastructure still includes these analog switches. When that capacity is filled by users, no new users can be accommodated. 
     Cable companies on the other hand, must deal with the issue of the “reverse path” problem. Cable networks were designed to deliver information one-way: from the television station to your home. The internet, on the other hand, requires data to flow in two directions, both to and from the computer. The only way to accommodate this two-way communication is to design special amplifiers to send the reverse signal upstream. The problem is that, as cable networks are designed as a hub and spoke system, problems with an amplifier in one spoke can compromise the entire wheel. 
     The utility is at a distinct disadvantage because it does not have an infrastructure across which to transmit large amounts of data. Utility lines connect to large, oil-filled power transformers to step-up and step-down voltage levels. As utility company can only “piggyback” data on top of electric power, these transformers limit data transmission to much slower rates. 
     There is thus a need for an improved data networking device. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates a power machine in accordance with the invention. 
     FIG. 2 illustrates one embodiment of a source sharing control circuit in accordance with the invention. 
     FIG. 3 illustrates a saturable core in accordance with the invention. 
     FIG. 4 illustrates an exemplary decision tree in accordance with the invention. 
     FIG. 5 illustrates a power machine with digital communications circuitry in accordance with the invention. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     A preferred embodiment of the invention is now described in detail. Referring to the drawings, like numbers indicate like parts throughout the views. As used in the description herein and throughout the claims, the following terms take the meanings explicitly associated herein, unless the context clearly dictates otherwise: the meaning of “a,” “an,” and “the” includes plural reference, the meaning of “in” includes “in” and “on.” Also, as used herein, the term “generator” is to mean any device capable of generating electric power. The term “microcontroller” and “microprocessor” are used interchangeably. 
     One embodiment of this invention includes a data communication device coupled to a distributed generation power machine. The power machine includes a source sharing control circuit capable of actuating the power machine as well as operating the power machine in a variety of configurations. The data communications device includes both a data communications link and data processing circuitry such that the power machine can provide a singular information gateway to a customer. This invention can efficiently and economically provide energy management capability and data communication services. 
     While telephone companies attempt to provide comprehensive communications to customers, they are prohibited by bandwidth. Approximately 25% of the U.S. telephone switching capacity is still analog with physical moving parts. These were designed to switch narrow-band signals and not be sufficient for future communications services. In addition, using statistical call figures, the switches were designed with at 20:1 service ratio. This ration insured that a call would be blocked less than 0.5% of the time due to system over usage. With the advent of the Internet and ISDN, a system with 10,000 lines could be clogged if 500 ISDN users left their computers on 24 hours a day. 
     Cable companies are better positioned than their telephone counterparts in terms of bandwidth, but they do have transmission issues. The original design of the cable system is similar to the power system. Signals were meant to travel in only one direction, and at the residential level, which is closer to a hub and spoke system than an interconnected grid. Consumers on the same spoke share a signal as opposed to the telephone system, which uses discrete point-to-point connections. As a result, the coaxial cable lines have enormous bandwidth but the lack of individual connections greatly complicate directed data transfer. While cable companies can employ packet headers like those used in cellular networks, this type of routing is much slower than desecrate connections. 
     Referring now to FIG. 1, a power machine as described in the parent application is illustrated. This embodiment  100  includes a source sharing control circuit  110  that configures power connection s between a power grid  102 , a local generator  142  and a local load  108 . Typically, the local load  108  includes electrical appliances situated at a local site  140  such as a house or place of business. The local generator  142 , and electric meter  104  and a fuel meter  106  would be at the local site  140 . The generator  142  may be a small capacity generator, including a micro-turbine generator, gasoline engine powered generator, fuel cell, Stirling engine, or other device capable of generating electric power. 
     The source sharing control circuit  110  receives information from an external data source  130 . The data source  130  could include an aggregator  132 , a data input form the electric meter  104  and a data input from the gas meter  106 . An aggregator is an entity that produces data regarding the economic costs involved in receiving power from the power grid  102  and ingenerating power from the generator  142 . For example, the aggregator  132  may provide the current price of electric power and the current price of natural gas for the generator. The aggregator  132  may, on the other hand, provide a simple binary indication of whether current price conditions favor local power generation versus taking power from the grid  102 . 
     The source sharing control circuit  110  includes a microprocessor  112  and a power circuit  120  that is capable of configuring power connections within the source sharing circuit  110  based on instructions received from the microprocessor  112 . The microprocessor  112  receives information from the data source  130  via a data port  114  and determines a preferred source-sharing configuration based upon the data received from the data port  114 . The microprocessor  112  instructs the power circuit  120  to affect the preferred source-sharing configuration. Such source sharing configurations include a first configuration  126  in which the local load  108  is fully powered by the local generator  142 ; a second configuration  128  in which the local load is fully powered by the local generator  142 , and a third configuration  124  wherein the local load  108  is partially powered by the power grid  102  and partially powered by the local generator  142 . The microprocessor  112  may also cause the power circuit  120  to isolate the local generator  142  from the power grid  102  upon sensing a power failure on the power grid  102 . 
     A possible fourth configuration  122  is possible, wherein the local load  108  is fully powered by the local generator  142  and wherein the power gird  102  receives power from the local generator  142 . This fourth configuration  122  allows the owner of the local generator  142  to sell power back to the grid  102 . The microprocessor  112  may have to be programmed to execute a net metering mode, wherein the microprocessor  112  monitors the electric meter  104  to determine the current value of the local utility bill and excludes the fourth configuration  122  when the current local utility bill value is not greater than a predetermined threshold value, such as zero. This mode would be used when local law prohibits the utility from having to pay for power received from a local generator in excess of a credit equal to an existing balance on a utility account. 
     Referring now to FIG. 2, one embodiment of a control circuit  210  is shown. The control circuit  210  includes an inverter  256  that converts direct current (DC) from the generator  242  into alternating current (AC). A saturable core reactor  252  controls the amount of AC that is allowed to flow from the power grid  202 . The AC from the inverter  256  is summed with the AC from the saturable core reactor  252  by a summation circuit  254  and then delivered to the load  208  A line sync signal  210  is tapped off of the power grid  202  to provide the inverter  256  with a sync input so that the output of the inverter  25  is synchronized with the output of the saturable core reactor  252 . While this embodiment includes the saturable core reactor, the control circuit could equally be made with a dual phase buck converter to step down the voltage level from the power grid  202 . 
     Referring now to FIG. 3, one embodiment of a saturable core reactor  352  is illustrated therein. The reactor  352  includes a first silicon steel core  354  and a second silicon steel core  356 . The first silicon steel core  354  includes a first outer winding  358  that receives AC power from the black line of a 220V power input from the power grid. The second silicon steel core  356  includes a second outer winding  360  that receives AC power from the red line of the 220V power input from the power grid. Both cores  354  and  356  have an inner winding  362  that is driven by the control signal from the DC drive circuit  350 . Thus, the amount of current that is allowed to flow through the outer windings  358  and  360 , and therefore the corresponding red and black lines, is a function of the strength of the control signal received from the DC drive circuit  350 . 
     Referring now to FIG. 4, a flow diagram illustrating the decision program embedded in the microprocessor of the control circuit is illustrated therein. This flow diagram is one illustrative embodiment of the many ways that the microprocessor can be programmed within the scope of the invention. The actual program employed would depend upon the specifics of the application for which the invention is to be used. 
     Referring now to FIG. 5, illustrated therein is a source sharing circuit having digital communication capabilities  600 . The source sharing circuit  610  comprises the microprocessor  114  and the power circuit  120  as previously described. Additionally, the source sharing circuit  610  includes a digital communications link  601  that is coupled to a decoder  602 . The decoder  602  is coupled to the microprocessor  112 , a audio/video converter  606  and to telephone lines  603 . An optional computer modem  607  is coupled to the microprocessor  112  and to a local area network (LAN)  605 . The microprocessor  112  is also coupled to a memory module  609 . 
     The digital communications link  601  is a two-way interface capable of sending and receiving data in digital form. The digital communications link  601  could be any of the following: telephone lines, electric power lines, fiber optics, ethernet networks, wireless communication, infrared communication links, lasers, satellites and coaxial cables. In a preferred embodiment, the digital communications link  601  comprises a connection to the internet through which one may access the source sharing circuit from devices including a computer, wireless personal data assistant, or wireless application protocol (WAP) phone. 
     In one embodiment, the digital communications link  601  can receive software commands that are transmitted to the microprocessor  112 . These commands may include information related to the status and actuation of the generator  142 , as well as actuation commands for the local load  108 . One example of controlling the local load  108  includes having appliances connected to a circuit breaker box coupled to the source sharing control circuit circuit  610 . If the user wants to turn on the air conditioning, for example, he may send an e-mail (a form of digital information) to the source sharing circuit  610  requesting that the microprocessor  114  actuate the air conditioner via the breaker box. 
     Other types of digital information may be transmitted across the source sharing control circuit  610  as well. For example, digital video and audio may be transmitted, including television broadcasts, movies and the like. In this scenario, the decoder  602  takes the digital bits transmitted in accordance with the transmission protocol and translates them into a binary format that the microprocessor  112  can understand. In this sense, the decoder  602  acts as a communications gateway. The microprocessor  112  then recognizes the difference between a video broadcast, which may use a digital satellite service (DSS) protocol, from an internet message, which might use a hypertext transfer protocol (HTTP). Once the difference is detected, the microprocessor  112  multiplexes the information to direct it to the appropriate device. 
     In the preceding example, the video signal would be sent to an Audio/Video converter  606  that converts the digital video to an analog signal capable of being viewed on a conventional television set. This signal is then sent to a television  604 . Essentially the decoder deals with the signal transmission protocol for media sent over a network. The other digital processors, like the audio/video converter  606  for example, then take the data after transmission and interpret it into meaningful information for that particular device. 
     In a likewise manner, the decoder  602  directs phone calls to conventional phone lines  603 . Digital information like web pages and e-mail are sent first to a remote computer modem  607  and then to a local area network (LAN)  605 . The remote computer modem may comprise a conventional modem and phone line or an Ethernet connection. The LAN may connect to computers, appliances and wireless computing devices. 
     The memory module  609  stores programs sent to the microprocessor  114  over the digital communication link. These programs may include actuation algorithms for appliances that tell them when to turn on or off. For example, if the user wants his air conditioning to come on every Monday, Wednesday, and Thursday at seven, but not until eight on Tuesday and Friday, this information would be stored in the memory module  609 . Additionally, the microprocessor  114  may monitor the run times of appliances to give the user a means to audit his energy usage. This information could equally be stored in the memory module  609  and later downloaded to a computer through the remote computer modem  607  and LAN  605 . The memory module  609  may be either volatile memory like random access memory (RAM), or non-volatile memory like an electrically erasable programmable read-only memory (EEPROM) or flash RAM. 
     While the preferred embodiments of the invention have been illustrated and described, it is clear that the invention is not so limited. Numerous modifications, changes, variations, substitutions, and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the following claims. For example, while the remote computer modem has been described as either a conventional modem or ethernet, the connection between a remote computer and the source sharing circuitry could be numerous other connections, including fiber optics, lasers, and wireless radio frequency connections.