Patent Application
20130214602
Not Applicable
Electrical generators serve many purposes and are commonplace in locations off of urban or commercial power grids (e.g., rural areas) or in locations that require back up power in the event of a power outage. Some of these locations include hospitals (e.g., for emergency back up power), schools, military base camps, and the like. Electrical generators typically require fuel such as gas or propane to power the motors that generate the electricity.
It can be exorbitantly expensive to generate electricity and maintain power grids (e.g., micro-grids) in remote areas due to the costs associated with fuel transport to these remote sites. The fully burdened cost of fuel (FBCF), or the effective cost per gallon, is one metric that can be used to measure these costs. Although commercial gas prices in the United States typically fluctuate between $2 to $4 per gallon depending on the region, gas prices can be several orders of magnitude higher in some scenarios. For example, U.S. military base camps in some of the most remote and mountainous regions in Afghanistan have micro-grid power arrays that are critical to the success of military operations. These sites may have no established shipping channels or commercial trade routes. Furthermore, large fuel caravans cannot be protected from improvised explosive devices (IEDs) or enemy combatants on a regular basis. As a result, large amounts of fuel have to be airlifted into these remote base camps to run the power generators. The FBCF in some of these regions can be as high as $400-$600 per gallon when considering the transport costs, personnel involved, and in many cases, the cost of human life in the process of procuring these fuel stores.
In addition to the high FBCF numbers, some military generator arrays operate in highly inefficient parallel configurations. Parallel configurations can protect against power outages since the operative units can compensate for inoperative units. However, parallel configurations tend to run at very low efficiency rates with light electrical loads. This is because parallel generator set configurations typically keep all generators running even with nominal electrical loads. For example, one original equipment manufacturer provides the U.S. Army with over 100,000 military generator sets and, by the Army's best estimates, these units are operating at approximately 17% to 20% capacity on average. The high FBCF numbers coupled with low generator set efficiencies, spread over tens of thousands of units results in massive economic waste. Furthermore, many generator units fail due to harsh military environments including extreme temperatures, large pressurization deltas (e.g., airlifting generator units), and impact (e.g., ordinance impact, shock waves, etc.) As such, improving generator robustness, fuel efficiency and cost effectiveness in high FBCF regions is desirable.
In certain embodiments, the present invention includes a system for generator set control comprising a controller and two or more power generators configured to supply power to an electrical load. The two or more power generators are coupled to the controller, where the controller is configured to synchronize the two or more power generators with one another. In some embodiments, the controller is configured to automatically shut off or turn on at least one of the two or more power generators in response to the electrical load to increase the overall power efficiency of the system. In further embodiments, the system is configured to operate in ambient temperature environments ranging from −55° C. to +125° C. The controller can be a digital controller, analog controller, or a combination therewith. Furthermore, the system can be configured to operate in a micro-grid array.
Some embodiments of the generator set control can include a battle short switch operable to maintain operation of the two or more power generators during a set of predetermined operating conditions including at least one of an over-voltage condition, an under-voltage condition, an over-current condition, or an under-current condition. In some embodiments, the generator set control further includes a display configured as an interface between a user and the controller, wherein the display comprises one or more heating elements to maintain a visibility of the display at temperatures down to −55 C. The controller can be operable to be controlled by a remote control device including one of a Bluetooth communication link, an infra-red (IR) communication link, Ethernet communication link, or radio-frequency (RF) communication link. In further embodiments, the system includes an external voltage bias coupled to the controller, where the external voltage bias is operable to provide a reference voltage to the controller.
A method of conserving fuel in a generator set is described herein. In certain embodiments, the method includes synchronizing the operating frequency of two or more power generators of the generator set. The method further includes controlling an amount of power supplied by the two or more generators to an electronic load. In some embodiments, the method includes automatically turning on or shutting off at least one of the two or more power generators based on a power requirement of the electronic load. In some cases, the method includes maintaining operation of the two or more generators when a battle short condition occurs. A battle short condition can occur when an over-voltage, over-current, under-voltage, or under-current condition exists.
In some embodiments, the at least one of the two or more power generators are turned on when a current number of generators that are turned on cannot supply the power requirement of the electronic load. In other cases, the at least one of the two or more power generators are turned off when a current number of generators that are turned on can supply power at a predetermined threshold above the power requirement of the electronic load. In one non-limiting example, the predetermined threshold is a maximum power that can be supplied by one power generator of the current number of generators that are turned on. In further embodiments, the method includes receiving operational commands from a remote control device to control the two or more power generators. In certain cases, the operation commands are received via data link which includes at least one of a Bluetooth communication link, an IR link, an RF link, or an Ethernet link.
Certain embodiments of the invention include a non-transitory computer-readable storage medium comprising a plurality of computer-readable instructions tangibly embodied on the computer-readable storage medium, which, when executed by a data processor, provides a method of conserving fuel in a generator set, the plurality of instructions including instructions that cause the data processor to synchronize the operating frequency of two or more power generators and instructions that cause the data processor to control an amount of power supplied by the two or more generators to an electronic load. In some embodiments, the non-transitory computer-readable storage medium further includes instructions that cause the data processor to automatically turn on or shut off at least one of the two or more power generators based on a power requirement of the electronic load. In some cases, at least one of the two or more power generators are turned on when a current number of generators that are turned on cannot supply the power requirement of the electronic load. Alternatively, at least one of the two or more power generators are turned off when a current number of generators that are turned on can supply power at a predetermined threshold above the power requirement of the electronic load. The predetermined threshold can be a maximum power that can be supplied by one power generator of the current number of generators that are turned on.
In further embodiments, the non-transitory computer-readable storage medium further includes instructions that cause the data processor to maintain operation of the two or more generators when a battle short condition occurs. The battle short condition can occur when at least one of an over-voltage, over-current, under-voltage, or under-current condition exists in the generator set system.
Embodiments of the invention are generally directed to systems and methods of controlling a generator set.
In an embodiment, a system for generator set control includes a controller and two or more power generators configured to supply power to an electrical load. The two or more power generators are coupled to the controller, where the controller is configured to synchronize the two or more power generators with one another. The controller can be configured to automatically shut off or turn on at least one of the two or more power generators in response to the electrical load to increase the overall power efficiency of the system. In some embodiments, the system is configured to operate in ambient temperature environments ranging from −55° C. to +125° C. The controller can be a digital controller, analog controller, or a combination therewith. Moreover, the system can be configured to operate in a micro-grid array. In further embodiments, the system includes a battle short switch operable to maintain operation of the two or more power generators during a set of predetermined operating conditions including at least one of an over-voltage condition, an under-voltage condition, an over-current condition, or an under-current condition. In yet further embodiments, the generator set control further includes a display configured as an interface between a user and the controller, wherein the display comprises one or more heating elements to maintain a visibility of the display at temperatures down to −55 C. The controller can be operable to be controlled by a remote control device including one of a Bluetooth communication link, an infra-red (IR) communication link, Ethernet communication link, or radio-frequency (RF) communication link. In further embodiments, the system includes an external voltage bias coupled to the controller, where the external voltage bias is operable to provide a reference voltage to the controller.
There are myriad types of generators that produce electrical energy, which can include gas, LPG (propane), natural gas, diesel, and others. A diesel generator can be the combination of a diesel engine with an electrical generator (i.e., alternator) to generate electrical energy. Diesel generating sets can be used in places without connection to a power grid (e.g., rural areas), as an emergency back up power-supply, military applications (e.g., micro-grids), as well as for more complex applications such as peak-lopping, grid support and export to the power grid. The combination of a diesel engine, a generator and various auxiliary devices (e.g., control systems, circuit breakers, fuel pumps, etc.) can be referred to as a “generating set” or a “gen set.”
The basic controller 120 is configured to control various operational functions of the generator set described herein. The basic controller 120 can control the amount of fuel the fuel pump 130 delivers to the diesel engine 150. The basic controller 120 controls the governor 135. The governor 135 can be operable to measure and regulate the speed of the diesel engine 150. In some embodiments, the basic controller 120 controls the AVR 145 and contactor 180. For example, the contactor 180 can be used to connect a generator 155 to the load board 190. The basic controller 120 can further control the synchronization of the phase and frequency of multiple generators 155 as well as the amount of power generated by the generators 155. The basic controller 120 and its functions would be appreciated by one of ordinary skill in the art with the benefit of this disclosure
The current transformers 160 can be used to measure electric currents. More particularly, current transformers 160 can be used for measuring current and monitoring the operation of a power grid, micro-grid, and the like. For example, current transformers 160 can measure the current generated by generator(s) 155 in response to a given electrical load. In some cases, when current in a circuit is too high to directly apply to measuring instruments, a current transformer can produce a reduced current accurately proportional to the current in the circuit, which can be connected to measuring and recording instruments. A current transformer can also isolate the measuring instruments from high voltages in a monitored circuit. As described above, the current transformers provide feedback to the basic controller 120 to facilitate aspects of gen set 100 control and regulation.
The AVR 115 is an automatic voltage regulator configured to automatically maintain a constant voltage level (e.g., voltage reference) for the generator 155. The AVR 115 can be a simple “feed-forward” design or may include negative feedback control loops. The AVR 115 can use an electromechanical mechanism, or electronic components, and can be used to regulate one or more AC or DC voltages.
The control panel 110 controls the basic controller 120. The control panel 110 can add automated controls to connect and/or disconnect additional generators 155 to the generator set based on the power requirements of an electronic load. The control panel 110 can further provide for remote control access to the gen set 100, support battle short modes of operation, and provide for a distributed system architecture of gen set control. The control panel 110 is further discussed below with reference to
The flash module 140 is a memory module that can be accessed by the control panel 110 and basic controller 120. Although flash memory is depicted in
The diesel engine 150 and generator(s) 155 generate electricity to provide a regulated power supply to a given electrical load. As described above, there are many types of generators that produce electrical energy (e.g., propane, gas, etc.) and the present invention is not limited to diesel embodiments. In exemplary embodiments, the gen set 100 can be configured to control multiple get set units in the 30 kW-60 kW output range, however the gen set 100 can also accommodate and control generators with a higher or lower output ranges.
The SBC 221 extends the capability of the basic controller 220 to allow system operational data to be logged internally in the generator. As further described below, the SBC 221 can be connected to a high resolution color display 206 that works over a wide military temperature range and is heated from behind (e.g., heating module 208) to allow operation at low temperature beyond what is normally possible for displays of this type. The SBC 221 further extends the functionality of the basic controller 220 by allowing setups for multiple generator voltages and frequencies to be automatically uploaded to the basic controller 220 when the configuration of the generator 200 is changed. A web server (not shown) can be incorporated into the SBC 221 to allow data to be downloaded from the SBC 221 using a web browser on another computer connected to the SBC 221 by hard-wired or wireless Ethernet connections. The data directory on the SBC 221 can also accessible, for example, via a Windows share over the network and remotely controlled by another computer using a VNC (Virtual Network Computing) viewer. Although the SBC 221 is not limited in the applications that it can run, some applications can include programs that provide for an internet connection, virtual client capabilities, and configuration data for reboot. Some of the capabilities provided by the SBC 221 include data logging to track operational data of the gen set (e.g., power output, efficiency, oil levels, water temperature, etc.), a user interface application to allow for remote control of the basic controller 220 and integration of the other applications (similar to remote control module 202), an application to display user manuals and troubleshooting guides, and a condition-based maintenance alert system to allow the connection of sensors in the generator 255A to the SBC 221 to determine when service items need to be replaced based on their condition and/or their timed cycles. Furthermore, the SBC 221 can be a gateway for several different communications protocols including Ethernet, Modbus TCP, CAN Open and CANJ1939.
In certain embodiments, the control panel 210A can be retrofitted to replace an existing generator control box requiring no external components, while maintaining the same size, fit, form factor, and control functionality. In some non-limiting examples, the control panel 210 can be used to implement a tactical micro-grid with a plug-and-play swap of the original equipment control box of DRS-Fermont™ gen sets, 30 kW-60 kW gen set units manufactured by L3 Communications MCII Electric Division™, AMMPS generators manufactured by Cummins-Onan™, and others. In some embodiments, the control panel 210A can be implemented in new gen set units without replacing existing control units. In further embodiments, the control panel 210A can be battle-hardened to pass all military qualification testing (“mil specs”) including temperature requirements (e.g., −55° C. to +125° C.) and other mil spec metrics that would be appreciated by one of ordinary skill in the art.
The control panel 210A is configured as a system integrator. In addition to controlling the gen set 200, the control panel 210A is operable to communicate with other gen set systems in a distributed network to start/stop a given number of gen sets to accommodate a certain power load on the power grid. Certain embodiments of the invention may include a digital control panel 210A, however analog or digital/analog hybrids can be implemented. The control panel 210A is configured for plug-and-play operation and cleanly integrates into the gen set 200, as described above. In some cases, the control panel 210A is configured to replace existing control panels in a plug-and-play drop-in configuration (e.g., older model DRS-Fermont gen sets using original equipment control panels, etc.). In other cases, the control panel 210A can be original equipment controllers in new gen set systems.
In distributed control systems, each gen set is independent and configured as equal entities with respect to each other such that any generator set in the system can still operate even if other gen sets are disabled. This is different than conventional master/slave configurations, which can be problematic if the master unit fails. Distributed systems provide for a robust and reliable power grid architecture because if one generator fails, shuts down, or is destroyed, other generators in the power grid will automatically come on-line to accommodate the particular power requirements of the electrical load. In other words, each of the gen sets operate independently from one another but communicate and coordinate power delivery with the other gen sets in the distributed power grid system. This concept is further described below with respect to
Circuit breakers are typically found on generators and are operable to shut down the generator during an electrical fault condition (e.g., short circuit) to protect the generator from damage. In some cases, maintaining the operation of the generator 255A and providing an uninterrupted power source to a power load can be of paramount importance, even at the risk of damaging the generator set 200. This may be true, for example, during critical military operations. A battle short module 204 causes the generator 255A to continuously run even though a fault condition may exist, by bypassing the protection units in the gen set 200 (e.g., circuit breakers). Some fault conditions may include an over-temperature condition, over voltage condition, under voltage condition, over current condition, or under current condition. The battle short module 204 can be engaged via the control panel 210A or it can operated independently as a stand alone unit. Furthermore, the battle short module 204 can be activated remotely from remote control module 202 or similarly wireless means. The battle short module 204 can be activated by mechanical switch, soft switch, though a graphical interface unit (GUI) such as an interactive display 206, or the like.
The remote control module 202 allows for remote access and control to the control panel 210A. This can be useful in certain applications where the control panels 210A are at long distances (e.g., a kilometer) from the generator 255A. Remote access to the control module 210A can also be useful to remotely activate the battle short module 204, for example, at a central command station. Any suitable communications protocol can be used (e.g., Modbus, CANbus, etc.), as would be known by those of ordinary skill in the art.
The display 206 can be a visual interface for a user to interact and control the gen set 200. The display 206 can be an active touch-sensitive graphical user interface (GUI), passive display, basic terminal, or any suitable visual interface. The display 206 is controlled by the control panel 210A via the basic controller 220. Alternatively, the control panel 210A can directly access and control the display 206. The gen set 200 is battle hardened (e.g., shock wave resistant) and operable at temperatures down to −55 degrees Celsius. At sub-zero temperatures, displays or monitors can become foggy and/or iced over, making monitoring and viewing the display 206 difficult or impossible. In some cases, the display 206 can become damaged, shattered, or inoperable due to condensation and the expansion and/or contraction caused by extreme temperature conditions. In some embodiments, a heating module 208 is coupled to the display 206. The heating module 208 can include heating elements (e.g., heater coils, heat sinks, etc.) configured in proximity to the display 206 (e.g., below, around the edges, etc.). The heating module 208 heats the display 206 to melt ice, evaporate condensation, etc., to provide for a clear and unobstructed viewing area in extreme sub-zero temperatures. In some embodiments, the heating module 208 can be controlled from the control panel 210A, from the display (e.g., by soft keys, mechanical buttons, or the like), via the remote control module 202, or through any other suitable means.
According to
At time t2, the power load 310 rises above 50 kW. The control panel of gen set 2 automatically starts, synchronizes its operating phase and frequency to gen set 1, and closes its breaker on the power grid. Gen set 2 supplements the power grid output to meet the power load 310 requirement as it remains between 50 kW and 100 kW. At time t3, gen set 2 is rendered inoperable (e.g., catastrophic electrical failure, destroyed, etc.) and is brought offline. As discussed above, Gen set 1 remains online but can only provide up to 50 kW output. The power grid detects the shut down of gen set 2 and automatically activates gen set 3. The control panel of gen set 3 starts up the generator, synchronizes its operating phase and frequency to gen set 1, and closes its breaker on the power grid. Gen set 3 supplements the power grid output to meet the power load 310 requirement as it remains between 50 kW and 100 kW. At time t4, the power load requirement 310 drops below 50 kW. The distributed power grid opens the gen set 3 circuit breaker and powers it down while gen set 1 continues to provide power to the electrical load. As described above, each generator set includes a control panel and basic controller to synchronize and control the other generator sets of the power grid.
Referring to
It should be appreciated that the specific steps illustrated in
It should be noted that certain embodiments of the present invention can perform some or all of the functions described herein. For example, some embodiments can perform all of the functions described in
The software components or functions described in this application may be implemented as software code to be executed by one or more processors using any suitable computer language such as, for example, Java, C++ or Perl using, for example, conventional or object-oriented techniques. The software code may be stored as a series of instructions, or commands on a computer-readable medium, such as a random access memory (RAM), a read-only memory (ROM), a magnetic medium such as a hard-drive or a floppy disk, or an optical medium such as a CD-ROM. Any such computer-readable medium may also reside on or within a single computational apparatus, and may be present on or within different computational apparatuses within a system or network.
The present invention can be implemented in the form of control logic in software or hardware or a combination of both. The control logic may be stored in an information storage medium as a plurality of instructions adapted to direct an information processing device to perform a set of steps disclosed in embodiments of the present invention. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will appreciate other ways and/or methods to implement the present invention.
In embodiments, any of the entities described herein may be embodied by a computer that performs any or all of the functions and steps disclosed.
Any recitation of “a”, “an” or “the” is intended to mean “one or more” unless specifically indicated to the contrary.
The above description is illustrative and is not restrictive. Many variations of the invention will become apparent to those skilled in the art upon review of the disclosure. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the pending claims along with their full scope or equivalents.
The following regular U.S. patent application and provisional applications, including this application, are being filed concurrently and the entire disclosure of the other applications is incorporated by reference into this application for all purposes: Application Ser. No. ______, filed Feb. 20, 2012, entitled “METHOD AND SYSTEM FOR GENERATOR CONTROL” (Attorney Docket No. 92741-815045(001200US)) (regular U.S. patent application);Application Ser. No. ______, filed Feb. 20, 2012, entitled “POWER DISTRIBUTION UNIT FOR POWER GRID MANAGEMENT” (Attorney Docket No. 92741-832341 (014600US)) (U.S. provisional patent application); andApplication Ser. No. ______, filed Feb. 20, 2012, entitled “SYSTEM AND METHOD FOR GENERATOR SET MONITORING AND CONTROL IN A POWER GRID” (Attorney Docket No. 92741-832340(0014500US)) (U.S. provisional patent application).
