Patent Document

FIELD OF INVENTION  
       [0001]     This disclosure relates generally to a system for providing electrical power and power conversion functionality in parallel with the utility services and especially to a system for a supplying multiple asynchronous electric power outputs from a single common electrical generation system.  
       BACKGROUND OF THE INVENTION  
       [0002]     Electrical power is distributed from large generation stations to end users through a network or grid of interconnected transmission lines. While the transmission system is interconnected at multiple points, during times of high electrical usage, or unexpected fault conditions, the utility company may be unable to deliver sufficient electrical power to users on some sections of the network. This condition may exist, for example, due to bottlenecks in the electrical distribution system created by the failure to expand capacity with the growth and development of a geographic area.  
         [0003]     During these periods of low electrical power availability, customers may experience a phenomenon known as a “brown-out” or a “black-out.” During a black-out, the customer experiences a total loss of electrical power. In a brown-out condition some electrical supply is retained, however the transmitted voltage is less than the allowable specification for the transmission network. Either situation will cause disruption to the end-user operations.  
         [0004]     To temporarily resolve power availability issues, utilities and electrical transmission companies have resorted to using portable power generators that may be moved and connected to the electrical network on a temporary basis. These portable generators are usually large diesel generators housed on a flatbed trailer. Coupled to these generators are transformers that allow the output of the diesel generator to have the proper characteristics to match those of the network that it is being connected. Typically the transformers are housed on a separate flatbed trailer to allow the mixing and matching of equipment. These systems will also have additional equipment that provides feedback to the generator controls that allows the electrical output to be synchronized with the electrical network.  
         [0005]     While this system of portable generation has provided emergency network power support, its application is limited by the systems ability to connect and synchronize with the electrical network. The portable generation system also has shortfalls when multiple electrical outputs are required, for example, where power is needed at a facility for critical load support where the facility has loads having different power requirements. While existing portable power systems are suitable for their intended purposes, there still remains a need for improvements in providing flexible power conversion systems that allows the achievement of appropriate levels of power quality, efficiency and reliability required for the end use loads. There is also a need for a portable generation system for supplying electrical power to multiple loads having asynchronous power characteristics. Further, there is a need for capturing heat from the portable generation system for use by a supported facility.  
       SUMMARY OF THE INVENTION  
       [0006]     The present invention provides a system for a self contained mobile power conversion station including a mobile support means for moving the station from a first location to a second location. A plurality of solid state power converters are mounted to the mobile support means and have an input for receiving raw electrical power and an output for producing regulated electrical power. A heat exchanger is mounted to the mobile support means and is coupled to the plurality of solid state power converters for removing heat during operation. A power inlet is mounted to the mobile support means and is coupled to the inputs on the power converters. A power outlet is mounted to the mobile support means and is coupled to the plurality of power converter outlets for transmitting the regulated electrical power to one or more end use loads.  
         [0007]     The present invention also provides for a mobile power station having a first mobile support with an electrical power generator. A second mobile support houses a plurality of solid state power converters where each of the power converters has an input electrically connected to the electrical power generator. Finally a third mobile support having a first electrical transformer is provided where the first transformer has an electrical input coupled to an output on at least one of the plurality of power converters. The first transformer is configured to output electrical power at a first predetermined set of characteristics.  
         [0008]     The mobile power station may also include a controller coupled to the plurality of solid state power converters where the controller has a user interface being configured to display predetermined operational parameters. The controller further includes a user activation means coupled to the controller, wherein there is exchange of data flow between the controller and the user activation means. The user activation means also comprises data receiving means adapted to receive data from transfer means selected from the group consisting of an electronic data card, voice activation means, manually-operable selection and control means, radiated wavelength and electronic or electrical transfer.  
         [0009]     The mobile power stations controller is also programmed for receiving a first signal from one of the plurality of power converters. The controller will retrieve a first operational parameter and a predetermined variance from a memory device electrically coupled to the controller and compares the first operational parameter to the first signal. A second signal is provided to the plurality of power converters and a third signal to the computer network wherein the controller and the memory device are operably coupled to a remote computer and the remote computer is configured to provide the first operation parameter to the memory device.  
         [0010]     Finally, an integrated mobile power station is provided that includes a movable support structure having a generator mounted thereon. A plurality of solid state power converters is also mounted to the movable support structure where each has an input electrically coupled to the generator and an output wherein each of the plurality of solid state power converter outputs has a different electrical power characteristic. A heat exchanger is also mounted to the moveable support structure and fluidly coupled to the plurality of power converters.  
         [0011]     The above discussed and other features will be appreciated and understood by those skilled in the art from the following detailed description and drawings.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     Referring now to the drawings, which are meant to be exemplary and not limiting, and wherein like elements are numbered alike:  
         [0013]      FIG. 1  is an illustration in perspective view of an exemplary embodiment portable power conversion system;  
         [0014]      FIG. 2  is a schematic illustration of a portable power generation and conversion system utilizing a single auxiliary generator to provide power to a utility electrical network;  
         [0015]      FIG. 3  is a schematic illustration of an alternate embodiment portable power generation and conversion system to provide electrical power to multiple asynchronous loads;  
         [0016]      FIG. 4  is a schematic illustration of an alternate embodiment portable power generation and conversion system including a means for utilizing heat from the system in a facility;  
         [0017]      FIG. 5  is a schematic illustration of an integrated portable power generation system; and,  
         [0018]      FIG. 6  is a schematic illustration of a controller used in a portable power and conversion system. 
     
    
     DESCRIPTION OF PREFERRED EMBODIMENT  
       [0019]     Traditionally, electrical power distribution and service was provided by a single utility which would provide all services required by a user, from the generation of the electricity, to the maintaining of the electrical grid. As the electrical power industry was deregulated, complexities often arose as consumers were allowed to purchase electricity from multiple suppliers over a transmission system owned by a third party. At the same time that deregulation has been implemented, customer power needs were increasing. Since the return on investment was uncertain, capital investments in the transmission systems were suppressed or delayed, thus creating bottlenecks in the electrical transmission network. These power deficiency bottlenecks are especially evident during periods of peak demand. To compensate for these deficiencies and to provide improvements in the cost effectiveness, reliability and maintenance of portable power generation, the present invention provides a mobile power generation and conversion system as shown in  FIGS. 1-6 .  
         [0020]     An exemplary embodiment of the present invention is shown in  FIG. 1 . In this embodiment, a power conversion system  10 , includes a series of solid state power converters  12 ,  14 ,  16  which receive alternating current (AC) electrical power from a generator  34 , such as a diesel generator ( FIG. 2 ). The power converters  12 - 16  are mounted on a mobile support platform  18 , which may optionally include a housing  20  for sheltering the power converters  12 - 16 . System  10  will further include a power inlet  22  and a power outlet  24  along with a user interface  26  and a controller  29 . In the preferred embodiment, the inlet  22 , outlet  24  and interface  26  are co-located on one side of the platform  18  to provide the user with capability of stationing the system  10  adjacent a building while still providing easy access to the electrical connections and monitoring units.  
         [0021]     As used herein, the mobile support platform includes, but is not limited to platforms, pallets, skids, rail cars and trailers for mounting the various pieces of power generation and conversion systems. The mobile support platform may be mounted on self-propelled transportation means (e.g. trucks, tractor-trailers, aircraft, or ships) or on transportation means which must be moved by separate locomotion (e.g. rail cars, trailers, barges, transportable skids and the like).  
         [0022]     A heat exchanger  28  having an external radiator  30  is coupled to each of the power converters  12 - 16 . Heat exchanger  28  provides a cooling fluid to heat exchanger internal to each power converter (not shown) to remove heat generated during operation. As will be discussed in more detail below, this heat may be reclaimed for further use. An optional hoist  32  to mounted to the roof of the housing  20  to facilitate the quick installation and removal of power converters  12 - 16  from the mobile platform  18 .  
         [0023]     Referring now to  FIG. 2 , the system  10  is shown incorporated into an electrical power network application. An electrical generator  34  produces electrical power to be used on a network  36 . The generator  34  is preferably a multi-megawatt scale generator capable of producing 60 Hz AC electrical power. More preferably, the generator  34  is a 2 MW, three-phase, diesel generator. However, the generator  34  may also produce electrical power have other characteristics including, but not limited to 50 Hz or 400 Hz frequency, single phase waveform, 480V, 220V or 110V. The generator  34  may be any type of distributed power generation device, including but not limited to electrical generators powered by hydrocarbon fueled (i.e. diesel, gasoline, propane or natural gas) internal combustion engines, hydrogen internal combustion engines, external combustion engines, Stirling engines, microturbines, steam turbines, gas turbines, flywheels, wind turbines, photovoltaic arrays, batteries, fuel cells (i.e. polymer electrode membrane, solid oxide, molten-carbonate, or phosphoric acid), capacitors, super-capacitors and ultracapacitors. In the exemplary embodiment, the generator  34  is mounted to a mobile platform separate from the power conversion system  10 .  
         [0024]     The electrical power from generator  34  is transmitted to the conversion system  10  through the inlet  22  where it is distributed to each of the solid state power converters  12 - 16 . In the exemplary embodiment the power converters  12 - 16  are similar to that described in U.S. Pat. No. 6,693,409 entitled “Control system for a power converter and method of controlling operation of a power converter” which is incorporated herein by reference. The power converters  12 - 16  may be of any type that can manage electrical characteristics such as, but not limited to, AC frequency, phase or voltage on either side of the converter and control the power flow at the same time. Preferably, the power converters  12 - 16  will automatically and independently adjust the electrical characteristics of the asynchronous electrical power produced by generator  34  to be compatible with the connected load and utility. In addition the power converters  12 - 16  preferably can control the reactive power on each side independently making possible some amount of voltage control on either side of the converter. This arrangement provides a number of advantages over the prior art systems in that this embodiment allows the generator  34  to operate in variable speed generator (“VSG”) mode to achieve improved performance and efficiency at partial loads. The VSG mode allows for operation during step changes in the load demand and the utilization of the rotational inertia of the generator  34  in compensating for these step changes.  
         [0025]     In the exemplary embodiment, the each power converter  12 - 16  contains two sections  12 A,  12 B,  14 A,  14 B,  16 A,  16 B to perform the power conversion. The “A” side of each power converter  12 A,  14 A,  16 A rectifies the incoming AC power from the generator  34  to produce a desired direct current (DC) electrical power. The rectifiers  12 A,  14 A,  16 A remove inherent power quality issues in the AC waveform created by the generator  34 . The DC power is passed from the rectifiers  12 A,  14 A,  16 A to an inverter  12 B,  14 B,  16 B that generates AC power with the appropriate characteristics needed by the electrical network  36 . In the preferred embodiment, each power converter  12 - 16  outputs regulated electrical power at 900 kVA with a voltage of 480V. The regulated electrical power exits the system  10  through the outlet  24  where it is carried by the electrical network  36  to end use loads  38 ,  40 . It should be appreciated that electrical network  36  may include transformers that are more or less permanently affixed to the network  36  and provide addition power regulation prior to distribution to end use loads  40 .  
         [0026]     Each of the power converters  12 - 16  is coupled to the heat exchanger  28  through at least a pair of conduits  44  that carry a cooling fluid such as water or glycol to each converter  12 - 16  where it passes through an internal heat exchanger. The cooling fluid absorbs heat in the internal heat exchanger and transports the heat back through the conduit  44  to the heat exchanger  28  which cools the fluid in the radiator  30  before circulating it back to the power converters  12 - 16 .  
         [0027]     The heat exchanger  28  operation is controlled by controller  29 . Controller  26  is a suitable electronic device capable of accepting data and instructions, executing the instructions to process the data, and presenting the results. Controller  29  may accept instructions through user interface  26 , or through other means such as but not limited to electronic data card, voice activation means, manually-operable selection and control means, radiated wavelength and electronic or electrical transfer. Therefore, controller  26  can be a microprocessor, microcomputer, a minicomputer, an optical computer, a board computer, a complex instruction set computer, an ASIC (application specific integrated circuit), a reduced instruction set computer, an analog computer, a digital computer, a molecular computer, a quantum computer, a cellular computer, a superconducting computer, a supercomputer, a solid-state computer, a single-board computer, a buffered computer, a computer network, a desktop computer, a laptop computer, a scientific computer, a scientific calculator, or a hybrid of any of the foregoing.  
         [0028]     Controller  29  is capable of converting the analog voltage or current level provided by sensors  50 ,  52  into a digital signal indicative of the electrical input from the generator  34  and output from the conversion system  10 . Alternatively, sensors  50 ,  52  may be configured to provide a digital signal to controller  26  , or an analog-to-digital (A/D) converter (not shown) maybe coupled between sensors  50 ,  52  and controller  26  to convert the analog signal provided by sensors  50 ,  52  into a digital signal for processing by controller  26 . Controller  29  uses the digital signals act as input to various processes for controlling the system  10 . The digital signals represent one or more system  10  data including but not limited to generator voltage, generator current, generator fuel supply, power converter temperature, power converter output voltage, power converter output current, or load power requirements.  
         [0029]     Controller  29  is operably coupled with one or more components of system  10  by data transmission media  54 . Data transmission media  54  includes, but is not limited to, twisted pair wiring, coaxial cable, and fiber optic cable. Data transmission media  54  also includes, but is not limited to, wireless, radio and infrared signal transmission systems. In the embodiment shown in  FIG. 2 , transmission media  54  couples controller  29  to power converters  12 - 16 , sensors  50 ,  52 , and heat exchanger  28 . Controller  29  is configured to provide operating signals to these components and to receive data from these components via data transmission media  54 .  
         [0030]     In general, controller  29  accepts data from sensor  50 ,  52  and power converters  12 - 15  , is given certain instructions for the purpose of comparing the data from sensors  50 ,  52  and power converters  12 - 16  to predetermined parameters. Controller  29  provides operating signals to power converters  12 - 16  and heat exchanger  28 . Controller  29  also accepts data from heat exchanger  28 , indicating, for example, whether the power converters are operating in the correct temperature range. The controller  29  compares the operational parameters to predetermined variances (e.g. high temperature range) and if the predetermined variance is exceeded, generates a signal that may be used to indicate an alarm to an operator or the computer network. Alternatively, the signal may initiate other control methods that adapt the operation of the system  10  to compensate for the out of variance operating parameter. For example, a high cooling fluid temperature returning from one of the power converter  12  may indicate an issue with that power converter  12 . To prevent damage to the equipment, the controller  29  may initiate a shut-down of the power converter  12 . In the preferred embodiment, the individual converters  12 - 16  would have capacity to accept the additional load created by a loss of a single power converter, enabling full operation of the system  10 .  
         [0031]     The data received from sensors  50 ,  52 , power converters  12 - 16  and heat exchanger  28  may be displayed on user interface  26 , which is coupled to controller  29 . User interface  26  is an LED (light-emitting diode) display, an LCD (liquid-crystal diode) display, a CRT (cathode ray tube) display, or the like. A keypad  56  is coupled to user interface  26  for providing data input to controller  29 .  
         [0032]     In addition to being coupled to one or more components within system  10 , controller  29  may also be coupled to external computer networks such as a local area network (LAN)  58  and the Internet. LAN  58  interconnects one or more remote computers  60 , which are configured to communicate with controller  29  using a well-known computer communications protocol such as TCP/IP (Transmission Control Protocol/Internet(ˆ) Protocol), RS-232, ModBus, and the like. Additional systems  10  may also be connected to LAN  58  with the controllers  29  in each of these systems  10  being configured to send and receive data to and from remote computers  60  and other systems  10 . LAN  58  is connected to the Internet  59 . This connection allows controller  29  to communicate with one or more remote computers  62  connected to the Internet  58 .  
         [0033]     Referring now to  FIG. 6  , a schematic diagram of controller  29  is shown. Controller  29  includes a processor  150  coupled to a random access memory (RAM) device  152 , a non-volatile memory (NVM) device  154 , a read-only memory (ROM) device  156 , one or more input/output (I/O) controllers  158  , and a LAN interface device  160  via a data communications bus  162 .  
         [0034]     I/O controllers  158  are coupled to power converters  12 - 16 , keypad  56 , and user interface  26  for providing digital data between these devices and bus  162 . I/O controllers  158  are also coupled to analog-to-digital (A/D) converters  164 , which receive analog data signals from sensors  50 ,  52  , and heat exchanger  28 .  
         [0035]     LAN interface device  160  provides for communication between controller  29  and LAN  58  in a data communications protocol supported by LAN  58 . ROM device  156  stores an application code, e.g., main functionality firmware, including initializing parameters, and boot code, for processor  150 . Application code also includes program instructions for causing processor  150  to execute any power conversion system operation control methods, including starting and stopping operation, monitoring predetermined operating parameters such as coolant fluid temperature, and generation of alarms. The application code creates an onboard telemetry system may be used to transmit operating information between the system  10  and a home terminal location and or/receiving locations while en route from the home terminal to a operating location. The information to be exchanged remote computers and the controller  29  include but are not limited to generator status, generator power output, input current, input voltage, power converter status, output voltage, output current, output power, load demands, coolant fluid temperature, geographic location, gps coordinates, and alarm status.  
         [0036]     NVM device  154  is any form of non-volatile memory such as an EPROM (Erasable Programmable Read Only Memory) chip, a disk drive, or the like. Stored in NVM device  154  are various operational parameters for the application code. The various operational parameters can be input to NVM device  154  either locally, using keypad  56  or remote computer  60 , or remotely via the Internet using remote computer  62 . It will be recognized that application code can be stored in NVM device  154  rather than ROM device  156 .  
         [0037]     Controller  29  includes operation control methods embodied in application code. These methods are embodied in computer instructions written to be executed by processor  150 , typically in the form of software. The software can be encoded in any language, including, but not limited to, assembly language, VHDL (Verilog Hardware Description Language), VHSIC HDL (Very High Speed IC Hardware Description Language), Fortran (formula translation), C, C++, Visual C++, Java, ALGOL (algorithmic language), BASIC (beginners all-purpose symbolic instruction code), visual BASIC, ActiveX, HTML (HyperText Markup Language), and any combination or derivative of at least one of the foregoing. Additionally, an operator can use an existing software application such as a spreadsheet or database and correlate various cells with the variables enumerated in the algorithms. Furthermore, the software can be independent of other software or dependent upon other software, such as in the form of integrated software.  
         [0038]     An alternate embodiment electrical power conversion system is shown in  FIG. 3 . In some applications, such as critical load support, it may be desirable to provide electrical power directly to a critical load rather than feeding the electrical power onto an electrical network. For example, if a generator  34  and power conversion system  10  are located at a telecommunications switching facility, there may be three distinct load requirements, 480V three phase to provide power to a network grid  36 , 120V single phase to provide primary power to the telecommunications facility loads, and 48V DC power for the telecommunications equipment. In this embodiment, the power conversion system  10  is configured to provide different electrical outputs from each power converter  12 - 16 . Here, the generator  34  provides AC electrical power onto a common bus that provides an input into each of the power converters  12 - 16 . The first power converter  12  rectifies  12 A the electricity and then inverts  12 B to provide  3  phase regulated power as in the exemplary embodiment. This electrical power is output to the network  36  for use by the end use loads. The second power converter  14  rectifies  14 A and inverts  14 B only a single phase of the AC power generated by generator  34  to produce 220V AC electrical power for use directly by load  64 . An optional transformer  66  may be incorporated to further vary the electrical characteristics of the output power from power converter  14 .  
         [0039]     Since loads  68 , such as telecommunications equipment requires DC electrical power, power converter  16  is configured to provide only the rectifier  16 A function to produce the necessary regulated power. This alternate embodiment provides several advantages over the prior art. In a typical prior art system, each load would have required a separate generator sized and configured to provide the electrical power type and characteristic needed by the end load. The additional generation systems would add significant cost, reliability and maintenance issues for the power producer.  
         [0040]     Another alternate embodiment is shown in  FIG. 4 . Here, the power converters are configured in the same manner as that illustrated in  FIG. 3 . Here, however, power conversion system  10  also reclaims the thermal energy Q produced by the power converters  12 - 16  to provide heat for heating of the facility  70 . The thermal energy is typically transferred to the facility in the form of direct heat, hot water, or steam for process heating and/or cooling. It should also be appreciated that while the heat reclamation is shown with respect to power converters  12 - 16 , it is also contemplated within the scope of this invention that heat may be captured from generator  34  to provide additional heat to facility  70 .  
         [0041]     An alternate embodiment power generation and conversion system is shown in  FIG. 5 . This embodiment includes an integrated mobile platform  200  such as a tractor  202  and trailer  205  wherein the trailer provides the mobile support means for mounting an integrated power generation and conversion system. A storage tank  210  is provided to store fuel required to operate the generator  215 . In the preferred embodiment, generator  215  includes a diesel fueled internal combustion engine that produces greater than 1 MW of 60 Hz three phase electrical power. More preferably, the generator produces at least 2 MW of 60 Hz three phase electrical power. However, the generator may be capable of producing power at other levels or with other characteristics, for example the electrical power may be produced at 50 Hz, 400 Hz, single phase, multi-phase or at different voltages including 480V, 220V, 110V. The generator  215  transfers the produced electrical power to a plurality of power converters  220 - 230  that convert and regulate the electrical power in the same manner as the described herein above in reference to  FIGS. 2-4 .  
         [0042]     A heat exchanger  235  is coupled with both the generator  215  and the power converters  220 - 230  to remove heat during operation. In the exemplary embodiment, the cooling fluid from the heat exchanger  235  is transferred to a radiator  250 , typically mounted on the roof of the trailer  205  where the heat is removed from the cooling fluid by the ambient air prior to returning to the heat exchanger  235  for reuse.  
         [0043]     The integrated mobile platform  200  also includes a controller  245  having a user interface, a process and communications functionality as that described above. The controller  245  is coupled to the generator  215 , storage tank  210 , heat exchanger  235 , and, power converters  220 - 230  to allow monitoring during operation and standby mode. An optional transformer  240  may be coupled to the power converters  220 - 230  to further adapt the output electrical power to the end user loads.  
         [0044]     It should be noted that the integrated mobile platform  200  is illustrated in  FIG. 5  installed on a closed trailer  205 . This trailer  205  may include doors for providing access, or fitted with swing-out or swing-up sides to allow for operation and maintenance when necessary. If desired, the trailer  205  may also be an open flatbed trailer, rail car, barge, ship or aircraft.  
         [0045]     While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, any modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention.

Technology Category: 5