Hybrid energy storage system, renewable energy system including the storage system, and method of using same

This disclosure generally relates to stabilizing energy provided by an energy source, and more particularly to systems and methods for using multiple types of energy storage devices to selectively capture and provide energy. An energy source provides energy, and the energy storage devices selectively capture energy provided by the energy source in excess of an immediate energy requirement of a load and selectively provide energy when the immediate energy requirement of the load exceeds the energy provided by the energy source.

FIELD

This disclosure generally relates to systems and methods for stabilizing energy provided by an energy source, and more particularly to systems and methods for using multiple types of energy storage devices to selectively capture and provide energy supplied by energy sources, including renewable and nonrenewable energy sources.

BACKGROUND OF THE INVENTION

As the world's population increases, consumer demand for electrical energy also increases. Fossil fuels (e.g., coal, oil, and natural gas) have been used as an energy source in electrical power plants for many years. Burning fossil fuels generates air pollutants such as carbon dioxide. These emissions may have a negative effect on the environment and may contribute to climate change. Further, to reduce air pollutants, some countries have passed laws that limit allowable air pollutants. These laws generally increase the cost of generating electrical energy from fossil fuels. Fossil fuel deposits around the world are being depleted because they are not being replenished at a rate commensurate with consumption. Access to fossil fuels is also often dependent on world political and economic conditions. These factors combine to cause increasing and unstable prices for energy generated from fossil fuels.

One solution to the problems of pollution from energy production via fossil fuels, diminishing fossil fuel deposits, increasing fossil fuel prices, fossil fuel price volatility, and government regulation is to use other energy sources, such as renewable energy sources, to generate electrical energy. Renewable energy sources such as wind, solar (e.g., photovoltaic), and geothermal are now available on a commercial basis, and the cost of electricity produced using these methods is generally decreasing as they become more prevalent and the underlying technologies are refined. Renewable energy sources thus provide potential solutions to the cost, availability, and environmental concerns associated with use of fossil fuels for electrical energy production.

One drawback associated with renewable energy sources is that their energy production may be affected by factors beyond the control of any operator such as darkness, lack of wind, or weather. For example, the sun does not shine all day every day, and the wind does not blow steadily all day every day. Therefore, solar cells and wind turbines cannot produce a steady energy output all day every day. However, it is desirable to achieve a relatively steady power output from these energy sources. Conversely, energy sources powered by fossil fuels such as gas turbine generators have a peak efficiency achieved at an output level determined by the design of the generator such that it is desirable to operate the generator at a specific output level associated with peak efficiency. However, as described above, energy demand may vary significantly. In each of these scenarios, a system for augmenting power provided by the energy source to the load is desirable.

SUMMARY

The present disclosure is directed to a method of stabilizing power provided by an energy source to a load. A first energy storage device captures energy produced by the energy source in excess of an immediate energy requirement of the load unless an energy level of the first energy storage device is at a first maximum threshold. A second energy storage device captures energy produced by the energy source in excess of the immediate energy requirement of the load if the energy level of the first energy storage device is at the first maximum threshold, unless an energy level of the second energy storage device is at a second maximum threshold. In one embodiment, another aspect of stabilizing power provided by the energy source to the load includes providing energy from the first energy storage device to the load when the immediate energy requirement of the load exceeds the energy produced by the energy source unless the energy level of the first energy storage device is at a first minimum threshold. If the energy level of the first energy storage device is at the first minimum threshold and the immediate energy requirement of the load exceeds the energy produced by the energy source, the second energy storage device provides energy to the load unless the energy level of the second energy storage device is at a second minimum threshold.

The disclosure is further directed to a system for providing power to a load. The system includes an energy source, a first energy storage device, a second energy storage device, and an energy flow controller. The energy source provides power and the first and second energy storage devices selectively capture power from the energy source and selectively provide power to the load. The energy flow controller includes a power monitor, a first energy level monitor, a second energy level monitor, an energy converter, and a controller. The power monitor monitors a difference between power provided by the energy source and an immediate energy requirement of the load and produces, for the controller, a power signal indicative of the monitored difference. The first energy level monitor monitors an energy level of the first energy storage device and provides, to the controller, a first energy level signal indicative of the energy level of the first energy storage device. The second energy level monitor monitors an energy level of the second energy storage device and provides, to the controller, a second energy level signal indicative of the energy level of the second energy storage device. The energy converter is responsive to a capture signal from the controller for selectively converting power from the energy source into power for at least one of the first and second energy storage devices and responsive to a switch signal from the controller for directing the converted power to at least one of the first energy storage device and the second energy storage device. The controller determines from the power signal that the energy provided by the energy source exceeds the immediate energy requirement of the load and provides the capture signal to the energy converter such that the energy provided by the energy source in excess of the immediate energy requirement of the load is captured in the first energy storage device unless the first energy level signal indicates that the energy level of the first energy storage device is at a first maximum threshold. If the first energy level signal indicates that the energy level of the first energy storage device is at the first maximum threshold, then the controller alters the switch signal such that the energy converter directs the energy in excess of the immediate energy requirement of the load to the second energy storage device unless the second energy level signal indicates that the energy level of the second energy storage device is at a second maximum threshold.

The disclosure is further directed to another method of stabilizing power provided by an energy source to a load. A first energy storage device captures energy produced by the energy source in excess of an immediate energy requirement of the load for a first predetermined amount of time unless an energy level of the first energy storage device exceeds a first maximum threshold. A second energy storage device captures energy produced by the energy source in excess of the immediate energy requirement of the load when the energy source continues to produce energy in excess of the immediate energy requirement of the load after expiration of the first predetermined amount of time or when the energy level of the first energy storage device is at the first maximum threshold, unless an energy level of the second energy storage device is at a second maximum threshold. In one embodiment, another aspect of stabilizing power provided by the energy source to the load includes providing energy from the first energy storage device to the load for a second predetermined amount of time upon the immediate energy requirement of the load exceeding the energy produced by the energy source unless the energy level of the first storage device is at a first minimum threshold. The second energy storage device provides energy to the load when the immediate energy requirement of the load continues to exceed the energy produced by the energy source following the second predetermined amount of time or when the energy level of the first energy storage device is at the first maximum threshold, unless the energy level of the second energy storage device is at a second minimum threshold.

The disclosure is further directed to another system for providing power to a load. The system includes an energy source, a first energy storage device, a second energy storage device, and an energy flow controller. The energy source provides power and the first and second energy storage devices selectively capture power from the energy source and selectively provide power to the load. The energy flow controller includes a power monitor, a first energy level monitor, a second energy level monitor, an energy converter, and a controller. The power monitor monitors a difference between power provided by the energy source and an immediate energy requirement of the load and produces, for the controller, a power signal indicative of the monitored difference. The first energy level monitor monitors an energy level of the first energy storage device and provides, to the controller, a first energy level signal indicative of the energy level of the first energy storage device. The second energy level monitor monitors an energy level of the second energy storage device and provides, to the controller, a second energy level signal indicative of the energy level of the second energy storage device. The energy converter is responsive to a capture signal from the controller for selectively converting power from the energy source into power for at least one of the first and second energy storage devices and responsive to a switch signal from the controller for directing the converted power to at least one of the first energy storage device and the second energy storage device. The controller determines from the power signal that the energy provided by the energy source exceeds the immediate energy requirement of the load and provides the capture signal to the energy converter such that the energy provided by the energy source in excess of the immediate energy requirement of the load is captured in the first energy storage device for a first predetermined amount of time unless the first energy level signal indicates that the energy level of the first energy storage device is at a first maximum threshold. If the first energy level signal indicates that the energy level of the first energy storage device is at the first maximum threshold or the energy source continues to produce power in excess of the immediate energy requirement of the load after expiration of the first predetermined period of time, then the controller alters the switch signal such that the energy converter directs the energy in excess of the immediate energy requirement of the load to the second energy storage device unless the second energy level signal indicates that the energy level of the second energy storage device is at a second maximum threshold.

The disclosure is also directed to another method of stabilizing power provided by an energy source to a load. A first energy storage device captures energy produced by the energy source in excess of an immediate energy requirement of the load up to an intake rate threshold of the first energy source. A second energy storage device captures energy produced by the energy source in excess of the sum of the immediate energy requirement of the load and the intake rate threshold of the first energy storage device. In one embodiment, the first energy storage device provides energy to the load when the immediate energy requirement of the load exceeds the energy produced by the energy source up to a discharge rate threshold of the first energy storage device. The second energy storage device provides energy to the load when the immediate energy requirement of the load exceeds the sum of the energy produced by the energy source and the discharge rate threshold of the first energy storage device up to a discharge rate threshold of the second energy storage device.

The disclosure is also directed to another method of stabilizing power provided by an energy source to a load. A first energy storage device captures energy produced by the energy source in excess of an immediate energy requirement of the load unless the energy produced in excess of the immediate energy requirement of the load exceeds an intake rate threshold of the first energy storage device. A second energy storage device captures energy produced by the energy source in excess of the immediate energy requirement of the load if the energy produced in excess of the immediate energy requirement of the load exceeds an energy intake rate threshold of the first energy storage device. In one embodiment, the first energy storage device provides energy to the load when the immediate energy requirement of the load exceeds the energy provided by the energy source and a difference between the immediate energy requirement of the load and the energy produced by the energy source is less than a discharge rate threshold of the first energy storage device. The second energy storage device provides energy to the load when the difference between the immediate energy requirement of the load and the energy provided by the energy source exceeds the discharge rate threshold of the first energy storage device.

One or more of the additional features detailed below may be incorporated into one or more of the above-noted embodiments, without departing from the scope of the present disclosure.

DETAILED DESCRIPTION

The following description is not intended to limit the scope or applicability of the invention in any way. Rather, the following description is intended to provide convenient illustrations for implementing various embodiments of the invention. As will become apparent, various changes can be made to the methods, structures, devices, systems, components, and compositions described in these embodiments without departing from the spirit and scope of the invention.

The term “renewable energy” as used within this disclosure refers to energy that is obtained from natural resources that are not depleted when energy is obtained from them. Examples of renewable energy sources include wind, solar, hydroelectric, biomass, and geothermal natural resources. As set forth in more detail below, various embodiments of the present invention provide systems and methods for integrating renewable energy sources into existing electrical systems.

Various embodiments of the invention include devices for rapid and accurate sensing of the loss of a renewable energy source or the loss of a transmission line to prevent or mitigate any interruption of the supply of electrical energy to users. Sensing of physical parameters as well as stochastic and/or adaptive control techniques may provide for optimal control, selection, switching, synchronization and other functions necessary to select and utilize one of several different energy storage devices available to supply energy to the user. For example, a voltage of an energy storage device may be sensed in order to determine a state of charge or energy level of the energy storage device. Further, multiple physical parameters such as temperature, cycle life, and voltage may be used to determine the state of charge or energy level of the energy storage device.

The term “hybrid energy storage system” as used within this disclosure refers to a single energy storage device (ESD) or multiple connected energy storage devices (e.g., an array of energy storage devices connected in a series and/or parallel arrangement) that store energy in different forms and in different ways for release at a later time. Examples of energy storage devices suitable for use in hybrid energy storage devices include electrochemical cells, batteries, fuel cells, capacitors, compressed air tanks, flywheels, pumped hydro systems, flow batteries, thermal storage systems, and the like. One skilled in the art will recognize that different energy storage devices have different characteristics useful in designing hybrid energy storage systems comprised of a combination of energy storage devices. For example, lithium or lithium ion based batteries are relatively expensive for a given capacity, have a relatively high energy density, and have a relatively high cycle life. Similarly, flywheels generally have an even higher cycle life, but they have a relatively high self discharge rate. In contrast, lead acid batteries are relatively inexpensive for the given capacity, have a relatively low energy density, and have a relatively low cycle life. Sodium sulfur based batteries have a balance of price for a given capacity, energy density, and cycle life. When designing a hybrid energy storage system, the available energy storage devices and their relative attributes may be mixed in various proportions to achieve the goals of the hybrid energy storage system within the constraints set by the location of the system and its intended use.

Some hybrid energy storage devices may be limited by location of the system. For example, compressed air typically requires large underground caverns or the like for compressed air storage, while pumped hydro systems generally require mountains, hills, dams, or the like to utilize mass and gravity for energy storage. Other hybrid energy storage devices may be portable. For example, electrochemical cells, batteries, fly wheels, and fuel cells may be trailer or truck mounted for rapid deployment to essentially any location.

In accordance with various embodiments of the invention, hybrid energy storage systems have sections, portions or separate energy storage devices, having different energy densities. For some hybrid energy storage systems, energy density is the ratio of the storage capacity to unit weight of the storage system. Other hybrid energy storage systems are better described by the ratio of storage capacity to unit volume. Both methods may be effective ways to measure the energy storage density of a hybrid energy storage system.

Exemplary hybrid energy storage systems additionally or alternatively may include sections, portions or separate energy storage devices, having different energy storage capacities. “Storage capacity” refers to how much energy may be stored in a given energy storage device or system. Storage capacity and energy storage density may largely determine how much power is available from a given hybrid energy storage system over a given a period of time.

The amount of power required by a load at a given time depends on several factors. For example, a residential home may require variable amounts of electrical power during daylight hours, but may require reduced and steady amounts of electrical power during nighttime hours. Likewise, a factory may require considerably more electrical power than a residential home and the required power may be relatively constant regardless of the time of day. Furthermore, by way of example, use of a computer or using a cell phone may require smaller amounts of electrical power for shorter periods of time. A plot of the amount of power or electrical energy required by a load versus time is herein referred to as the expected energy requirement profile of the load.

As used herein, “energy” refers to the product of power and time. Optimization of a hybrid energy storage system for use with an energy source may be dependent on the physical characteristics and application of the load including (but not limited to) an expected energy requirement profile of the load, the energy density of the hybrid energy storage system, the location of the energy source, the type of energy source, the location of the hybrid energy storage system, and the portability of the hybrid energy storage system.

Referring toFIG. 1, a renewable energy system102includes a renewable energy source104, an energy converter106, AC electrical energy108, transmission lines110, a load112, an energy flow controller114, and a hybrid energy storage system116.

The renewable energy system102is configured to provide alternating current (AC) electrical energy108to the load112from the renewable energy source104. Energy from the renewable energy source104is converted to AC electrical energy108and its phase and frequency are corrected by the energy converter106. The AC electrical energy108is transmitted to the load112through the transmission lines110. The load112may be a single user, consumer, factory, community, or an electrical grid used to distribute AC electrical energy to any number of consumers, users, factories, or communities. Similarly, the load112may be a portion of a dwelling such as a home or factory (e.g., a single circuit within the dwelling) or multiple dwellings such as multiple homes or factories.

When the renewable energy source104is not providing energy because of weather or other disturbances, the load112receives the AC electrical energy118from the hybrid energy storage system116. Similarly, when the transmission line110becomes inoperable because of weather or other disturbances, the load112receives AC electrical energy118from the hybrid energy storage system116. The hybrid energy storage system116may be located either close to the load112or some distance from the load112. If the hybrid energy storage system116is located some distance from the load112, either the transmission lines110may be configured and connected to the hybrid energy system116to provide the AC electrical energy118to the load112or another suitable transmission device may be used. When the hybrid energy storage system116is depleted, the load112may not receive AC electrical energy118from the hybrid energy storage system116unless or until the hybrid energy storage system116has been replenished. The hybrid energy storage system116may be replenished by energy flow controller114via the renewable energy source104or some other energy source (not shown) managed by the energy flow controller114.

Referring toFIG. 2, a more detailed block diagram of the renewable energy system102illustrates a sense component120and storage control122of the energy flow controller114. In the illustrated example, the energy flow controller114includes a sense component120and a storage control122configured to sense, determine, react to, and control the loss of the renewable energy source104and/or loss of the transmission lines110function.

The sense component120may be configured to facilitate determining an energy output provided by the renewable energy source104and/or loss of the transmission lines110by sensing one or more physical parameters of the renewable energy source104and/or the transmission lines110. These physical parameters may include (but are not limited to) voltage, current, time, temperature, and strain.

Direct physical contact between the sense component120and/or the renewable energy source104and/or the transmission lines110may be utilized to facilitate accurate measurement of the physical parameters. For example, measuring voltage may utilize a direct connection of voltmeter probe(s) to the renewable energy source104and/or the transmission lines110, and temperature measurement may utilize direct physical contact of a thermistor or thermometer to the renewable energy source104and/or the transmission lines110. Direct physical contact methods of measurement include (but are not limited to) analog, digital and/or other comparison techniques.

Indirect methods may also be utilized to measure the physical parameters associated with the renewable energy source104and/or the transmission lines110. For example, measuring the physical parameters may not be possible using direct measurement techniques because the renewable energy source104and/or the transmission lines110may be isolated or in a remote (or inaccessible) location. Indirect measurement techniques may include (but are not limited to) inductive coupling, capacitive coupling, and optical coupling.

The storage control122may be implemented as hardware, software or a combination of both. The storage control122may be programmable, and may receive input from the sense component120. The storage control122may apply application logic to input signal(s), for example, signals received from the sense component120, and may provide output signal(s) for further system use, including supplying energy to the hybrid energy storage116. The storage control122may use stochastic and/or adaptive control techniques (i.e., learning algorithms) to provide for optimal control, selection, switching, synchronization and any other functions necessary to select and use one of several different energy storage devices available to capture (i.e., store) energy and supply the AC electrical energy to the load112.

Referring toFIG. 3, a more detailed block diagram of the renewable energy system102, illustrates one embodiment of the hybrid energy storage system116in detail. In the exemplary embodiment ofFIG. 3, the hybrid energy storage system116comprises the energy conversion124, the energy storage devices126, and the energy conversion128.

The energy conversion124provides for conversion of AC electrical energy into a compatible form of energy for storage or capture in a particular energy storage medium or device. The energy conversion124may facilitate replenishing the energy in energy storage126after depletion, or at any charge level of energy storage126. Various components may provide systems and methods for converting energy for storage in the energy storage devices126. For example, AC electrical energy may be used to power an air compressor to produce compressed air for storage in a cavern or tank. Furthermore, by way of example, electrical energy may be used to power a battery charger, alternator, or other electrical machine for charging an electrochemical cell or battery.

The energy storage devices126store or capture energy provided by the energy conversion124for later providing the stored energy to the energy conversion128such that the stored energy may be supplied by the energy conversion128to the load112as AC electrical energy (i.e., power). For example, a first energy storage device might be an electrochemical cell, battery, or array thereof; a second energy storage device might be a group of fuel cells; and a third energy storage device of the energy storage devices126might be a pumped hydro storage medium. The quantity (number) and types of energy storage mediums used in the energy storage devices126is dependent upon the configuration and location of the renewable energy system, a desired energy density of the renewable energy system102, and a desired capacity of the renewable energy system102. One skilled in art will appreciate that these design considerations will vary from system to system. For example, one renewable energy system102may utilize two different energy storage mediums in energy storage devices126, while a different renewable energy system102may utilize four different energy storage mediums in energy storage devices126. Energy storage devices are generally selected to minimize the overall operating expense of the hybrid energy storage system. The overall operating expense includes initial purchase of materials, installation, and maintenance over the useful life of the hybrid energy storage system. In one embodiment of a hybrid energy storage system scalable to most installations, the 10% of the energy storage capacity is achieved via lithium ion battery, 30% of the energy storage capacity is achieved via sodium sulfur battery, and 60% of the energy storage capacity is achieved via lead acid battery. The lithium ion battery is used for the majority of cycles (i.e., storage or discharge to stabilize the power provided from the energy source104to the load112) due to its high cycle life and high price for a given capacity. The sodium sulfur battery is used for longer or deeper cycles due to its balance of cycle life and price for a given capacity. The lead acid battery is used for very long cycles because of its low price for a given capacity and low cycle life. By combining the strengths of these various energy storage device types in various proportions, initial purchase and installation costs can be reduced along with maintenance costs, and overall service life can be maximized for the constraints presented by the given installation.

The energy conversion124converts the stored energy in the energy storage devices126into AC electrical energy118for transmission to the load112. Generally, the energy stored in the hybrid energy storage system116is not in a form compatible with an electric grid (e.g., transmission lines110) or in phase with and of the same frequency as energy being supplied to a user. Various systems and methods are utilized to convert energy from a particular energy storage medium into AC electrical energy118for transmission to the load112. For example, releasing energy from a pumped hydro reservoir involves releasing water from the reservoir and allowing gravity to draw the released water through a turbine that turns an electrical generator that produces AC electrical energy118. In one embodiment, this system would also include a device for matching the phase and frequency of the AC electrical energy118to energy already being supplied to the load112. As another example, a fuel cell may be the energy input to an inverter that produces AC electrical energy118as an output. As another example, an inverter is used to convert energy from an electrochemical cell into AC electrical energy118.

Referring toFIG. 4, one embodiment of the storage control122comprises various functional elements, such as an analog to digital converter130, a timer function132, a central processing unit (CPU) function134and a communication function136.

Elements of the storage control122may be implemented as hardware, software or a combination of both. Stochastic and/or adaptive control techniques may provide for optimal control, selection, switching, synchronization and other functions to select and utilize one of several different energy storage devices126available to supply energy for conversion to AC electrical energy118to load112. In addition, AC electrical energy is supplied as available to hybrid energy storage system116to replenish and maintain desired or optimum energy levels in the energy storage devices126. Other functions may be present in storage control122without departing from the scope of this disclosure such as energy balancing between the energy storage devices126.

Communication and control among the components of the system102may be accomplished through any suitable communication channels, such as, for example, a telephone network, an extranet, an intranet, Internet, point of interaction device (point of sale device, personal digital assistant (e.g., Palm Pilot®, Blackberry®, cellular phone, kiosk, etc.), online communications, satellite communications, off-line communications, wireless communications, transponder communications, local area network (LAN), wide area network (WAN), virtual private network (VPN), networked or linked devices, keyboard, mouse and/or any suitable communication or data input modality. Further, the communications protocol between the components may include both serial and parallel data transmission.

Referring toFIG. 5, a method500for using a plurality of hybrid energy source storage mediums and devices of varying capacities for stabilizing power provided by a renewable energy source is shown. At138, the CPU function134determines if renewable energy source104is available. If the renewable energy source is not available, the CPU function134, at step150, selects a hybrid energy storage device or system for supplying energy for conversion into AC electrical energy at step152. The AC electrical energy from step152is transmitted to load112at step148. If the renewable energy source is available at step138, then the renewable energy is converted into AC electrical energy at step140. At step142, the CPU134determines if the hybrid energy storage system116should be replenished. If the hybrid energy storage system116is to be replenished, AC electrical energy is supplied at step144to the hybrid energy storage system116and the CPU function134proceeds to step146. If the hybrid energy storage116is not to be replenished, then the process moves to step146from step142. At step146, the availability of the transmission line110is determined by CPU function134. If the transmission line110is not available, the CPU function134moves to step150where the optimum energy storage device is selected. If the transmission line110is available at step146, AC electrical energy is transmitted to the load122at step148from the optimum energy storage device via an appropriate energy conversion.

It should be understood that the process illustrated above may be closed loop and iterative, and that the processes or method may include other optional steps without departing from the scope of the invention. Various functional elements in the energy flow control114, such as the analog to digital converter130, the timer function132, the CPU function134, and the communication function136are used to facilitate sensing, control and communications within the renewable energy system102.

Referring toFIG. 6, a system600provides energy to a load602. The system600includes an energy source604, an energy flow controller606, a first energy storage device608, and a second energy storage device610. The first energy storage device608and second energy storage device610make up a hybrid energy storage system612. The energy source604may be a renewable energy source such as a wind turbine or a solar panel providing a relatively variable power supply, or a nonrenewable energy source such as a gas turbine providing a relatively constant power supply. In either case, an immediate energy requirement of the load602varies, and the energy flow controller606selectively stores energy in the energy storage devices and provides power from the energy storage devices such that the immediate energy requirement of the load602is met.

One skilled in the art will recognize that the energy flow controller606may directly connect the energy source604to the load602and selectively capture and provide energy to this connection, or the energy flow controller606may contain phase, frequency, and amplitude matching devices necessary for connecting the energy source604to the load. Further, in one embodiment, the energy flow controller606manages multiple energy sources to meet the immediate energy requirement of the load602. For example, in one embodiment, a gas turbine is directly connected to the load602, a wind turbine is connected to the load602via the energy flow controller606, and the energy flow controller selectively stores energy from the wind turbine and gas turbine as a function of the power being provided by each energy source and the immediate energy requirement of the load602. One skilled in the art will also recognize that the system600may include any number and type of energy sources and energy storage devices as described above. In one embodiment, a first energy storage device is a lithium based electrochemical cell accounting for 10% of the total storage capacity of the energy storage devices, a second energy storage device is a sodium sulfur or NiCad electrochemical cell accounting for 30% of the total storage capacity of the energy storage devices, and a third energy storage device is a lead acid electrochemical cell accounting for 60% of the total storage capacity of the energy storage devices.

Referring toFIG. 7, the energy flow controller606comprises an energy converter702, a controller704, a power monitor706, a first energy level monitor708, and a second energy level monitor710. The energy converter702receives power from the energy source604and converters the power for storage in either of the first energy storage device608and second energy storage device610, or provides the power to the load602. In one embodiment, at least one of the energy storage device608,610is an electrochemical cell, and the energy converter702comprises a rectifier for converting power from the energy source604into energy for storage in at least one of energy storage devices608,610, and an inverter for converting energy from at least one of the energy storage devices608,610into power for the load602. Optionally, the energy converter matches the amplitude, frequency, and phase of the power to the load602. The energy converter also converts energy stored in the first energy storage device608and second energy storage device610into power for use by the load602. Additionally, the energy converter contains a switch matrix or array of energy conversion devices for transferring energy between the energy storage devices (e.g., first and second energy storage devices608and610). In one embodiment, the energy storage devices,608,610include energy conversion components for converting energy stored in the energy storage device into a form useful to the energy converter702.

The monitors706,708,710or sensors provide signals indicative of certain conditions to the controller704. The power monitor706(i.e., power sensor) provides a power signal indicative of an immediate energy requirement of the load602to the controller704. In one embodiment, the power signal is indicative of a difference between the power provided by the energy source604and the immediate energy requirement of the load604. In another embodiment, the power signal is indicative of a voltage at the load602. The first energy level monitor708provides a first energy level signal to the controller704indicative of an energy level of the first energy storage device608. The second energy level monitor710provides a second energy level signal to the controller704indicative of an energy level of the second energy storage device610. In one embodiment, the first and second energy level signals are indicative of a voltage of the respective energy storage devices. In another embodiment, the first and second energy level signals are indicative of a state of charge of the respective energy storage devices determined as a function of at least one of: a voltage of the respective energy storage devices, a capacity of the respective energy storage devices, a temperature of the respective energy storage devices, a strain of the respective energy storage devices, and a current of the respective energy storage devices.

The controller704is responsive to the power signal, first energy level signal, and the second energy level signal for instructing the energy converter702to selectively capture and/or store energy in each of the energy storage devices (e.g., first and second energy storage devices608and610). In one embodiment, the controller704instructs the energy converter702by selectively providing a capture signal, a switch signal, a discharge signal, a first transfer signal, and a second transfer signal to the energy converter702. One skilled in the art will recognize that these signals may be provided by way of a parallel or serial communication system. That is, each signal may be provided on a dedicated line to the energy converter702, or the signals may be transmitted to the energy converter702as a set of states of the signals via a packet of information in a serial transmission format. The energy converter702is responsive to the capture signal for storing energy provided by the energy source604in at least one of the energy storage devices608,610. The energy converter702is responsive to the switch signal for operating a switch matrix or array of energy conversion devices within the energy converter702to direct energy being stored to at least one energy storage device selected by the controller704or for determining which of the energy storage devices to extract energy from for conversion and supply to the load602. The energy converter702is responsive to the discharge signal for extracting energy from at least one of the energy storage devices608,610, converting the extracted energy to power for the load602, and providing the power to the load. The energy converter702is responsive to the first transfer signal for transferring energy from the first energy storage device608to the second energy storage device610. The energy converter702is responsive to the second transfer signal for transferring energy from the second energy storage device610to the first energy storage device608.

Referring toFIG. 8, a method of selecting an energy storage device for capturing energy provided by the energy source604in excess of the immediate energy requirement of the load602begins at802. At804, the controller704determines whether energy provided by the energy source604exceeds the immediate energy requirement of the load602. If the energy provided by the energy source604does not exceed the immediate energy requirement of the load602, then the method ends at806. If the energy provided by the energy source604exceeds the immediate energy requirement of the load602, then the controller704determines whether the first energy storage device608is available at808. In one embodiment, determining whether the first energy storage device608is available comprises at least one of: determining whether the energy level of the first energy storage device608is at a maximum threshold of the first energy storage device608, determining whether a temperature of the first energy storage device608exceeds a predetermined temperature limit, determining whether a number of cycles of the first energy storage device608exceeds a predetermine cycle limit, determining whether a storage discharge efficiency of the first energy storage device608has decreased below a predetermined minimum, and determining whether a strain of the first energy storage device608exceeds a predetermined strain. If none of these adverse conditions is present (or a condition is not tested for) in the first energy storage device608, the controller determines that the first energy storage device608is available and proceeds to store energy in the first energy storage device at810and continues back to804. If the first energy storage device608is not available, then the controller704proceeds to determine whether the second energy storage device610is available at812. In one embodiment, the second energy storage device610is a sodium sulfur electrochemical cell and availability is determined based on conditions similar to those of the first energy storage device608. If the second energy storage device610is available at812, then the controller instructs the energy converter702to capture (i.e., store) energy in the second energy storage device610at814and proceeds back to804. If the second energy storage device610is not available at812, then the controller704ends at806. Optionally, the controller704may instruct the energy converter704to reduce the flow of power form the energy source604to the load602to protect the load602from excessive power. One skilled in the art will recognize that the controller704can be configured to instantly interrupt the method ofFIG. 8in response to the immediate energy requirement of the load602exceeding the power provided by the energy source604.

Referring toFIG. 9, a method of selecting an energy storage device for capturing energy provided by the energy source604in excess of the immediate energy requirement of the load602begins at902. At904, the controller704determines whether energy provided by the energy source604exceeds the immediate energy requirement of the load602. If the energy provided by the energy source604does not exceed the immediate energy requirement of the load602, then the method ends at906. If the energy provided by the energy source604exceeds the immediate energy requirement of the load602, then the controller704determines whether the first energy storage device608is available at908. If the controller determines that the first storage device608is available at908, the controller704proceeds to capture energy in the first energy storage device at910and continues to912. At912, the controller704determines whether energy has been being captured in the first energy storage device for a first predetermined amount of time. If energy has not yet been being captured in the first energy storage device608for the first predetermined amount of time, then the controller704proceeds back to912. Alternatively, if energy has been being captured in the first energy storage device608for the first predetermined amount of time, then the controller704proceeds to determine whether the second energy storage device is available at914. Similarly, if the controller704determines that the first energy storage device608is not available at908, then the controller proceeds to914. At914, the controller704determines whether the second energy storage device610is available. If the second energy storage device610is available at914, then the controller704instructs the energy converter702to capture (i.e., store) energy in the second energy storage device610at916and proceeds back to904. If the second energy storage device610is not available at914, then the controller704ends the process at906. Optionally, the controller704may instruct the energy converter704to reduce the flow of power form the energy source604to the load602to protect the load602from excessive power. One skilled in the art will recognize that the controller704can be configured to instantly interrupt the method ofFIG. 9in response to the immediate energy requirement of the load602exceeding the power provided by the energy source604.

Referring toFIG. 10, a method of selecting an energy storage device to extract energy from to subsequently convert and provide to the load602begins at1002. At1004, the controller704determines whether the immediate energy requirement of the load602exceeds the energy provided by the energy source604. If the immediate energy requirement of the load602does not exceed the energy being provided by the energy source604, then the process ends at1006. If the immediate energy requirement of the load602exceeds the energy being provided by the energy source604, then the controller704continues to1008and determines whether the first energy storage device608is available. Availability of the first energy storage device608for discharge is determined based on the same conditions as for capturing energy in the first energy storage device608except that the controller704determines whether the energy level of the first energy storage device608is at a first minimum threshold instead of a first maximum threshold. If the first energy storage device608is available at1008, then the controller704provides the appropriate signals to the energy converter702such that the energy converter extracts energy from the first energy storage device608, converts the energy to power for the load602and provides the converted power to the load602at1010. If the first energy storage device608is not available at1008, then the controller proceeds to1012and determines whether the second energy storage device is available. If the second energy storage device610is not available, then the process ends at1006. If the second energy storage device610is available, then the controller704provides the appropriate signals to the energy converter702such that the energy converter702extracts energy from the second energy storage device610, converts the energy to power for the load602and provides the converted power to the load602at1014. The controller704then proceeds back to1004. One skilled in the art will recognize that the controller704can be configured to instantly interrupt the method ofFIG. 10in response to the power provided by the energy source604meeting and/or exceeding the immediate energy requirement of the load602.

Referring toFIG. 11, a method of selecting an energy storage device to extract energy from to subsequently convert and provide to the load602begins at1102. At1104, the controller704determines whether the immediate energy requirement of the load602exceeds the energy provided by the energy source604. If the immediate energy requirement of the load602does not exceed the energy being provided by the energy source604, then the process ends at1106. If the immediate energy requirement of the load602exceeds the energy being provided by the energy source604, then the controller704continues to1108and determines whether the first energy storage device608is available. Availability of the first energy storage device608for discharge is determined based on the same conditions as for capturing energy in the first energy storage device608except that the controller704determines whether the energy level of the first energy storage device608is at a first minimum threshold instead of a first maximum threshold. If the first energy storage device is available at1108, then at1110, the controller704then determines whether energy has been being provided from the first energy storage device for a second predetermined amount of time. If the controller704determines that the first energy storage device608is available at1108and that energy has not been being provided from the first energy storage device608to the load602for the second predetermined amount of time, then the controller704provides the appropriate signals to the energy converter702such that the energy converter702extracts energy from the first energy storage device608, converts the energy to power for load602and provides the converted power to the load602at1010. If the controller704determines that the first energy storage device608is not available at1108or that energy has been being provided from the first energy storage device608to the load602for the second predetermined amount of time at1110, then the processor704proceeds to determine whether the second energy storage device610is available at1114. If the second energy storage device610is not available, then the process ends at1106. If the second energy storage device610is available, then the controller704provides the appropriate signals to the energy converter702such that the energy converter702extracts energy from the second energy storage device610, converts the energy to power for load602and provides the converted power to the load602at1116. The controller704then proceeds back to1104. One skilled in the art will recognize that the controller704can be configured to instantly interrupt the method ofFIG. 11in response to the power provided by the energy source604meeting and/or exceeding the immediate energy requirement of the load602.

Referring toFIG. 12, a method of capturing energy provided by the energy source604in excess of the immediate energy requirement of the load602begins at1202. At1204, the controller704determines whether the energy provided by the energy source604exceeds the immediate energy requirement of the load602, and if not, the process ends at1206. If the energy provided by the energy source604exceeds the immediate energy requirement of the load602, then the controller704determines whether the first energy storage device608is available for capturing energy at1208. If the first energy storage device608is available, then the controller704sends the appropriate signals to the energy converter702such that energy is captured in the first energy storage device608up to an intake rate threshold of the first energy storage device608at1210. At1212, the controller704determines whether the difference between the energy provided by the energy source604and the immediate energy requirement of the load602exceeds the intake rate threshold of the first energy storage device608. If the difference between the energy provided by the energy source604and the immediate energy requirement of the load602does not exceed the intake rate threshold of the first energy storage device608, then the controller704proceeds back to1204. If the difference between the energy provided by the energy source604and the immediate energy requirement of the load602exceeds the intake rate threshold of the first energy storage device608, then the controller704proceeds to determine whether the second energy storage device610is available at1214. If the second energy storage device610is not available, then the controller704proceeds back to1204. If the second energy storage device610is available, then the controller704sends the appropriate signals to the energy converter702such that the second energy storage device610captures the energy provided by the energy source604in excess of the sum of the immediate energy requirement of the load602and the intake rate threshold of the first energy storage device608at1216, and the controller proceeds back to1204. One skilled in the art will recognize that the method ofFIG. 12can also be applied when discharging the energy storage device608,610in order to match the power output of the energy flow controller606to the immediate energy requirement of the load602. In one embodiment, the controller704varies the intake rate threshold of the first energy storage device, the intake rate threshold of the second energy storage device, the discharge rate threshold of the first energy storage device, and the discharge rate threshold of the second energy storage device as a function of at least one of: a cooling capacity associated with the energy storage device, a heat dissipation coefficient of the energy storage device, an expected ambient air temperature profile, an expected energy requirement of the load, an expected cycle rate profile, and an energy production profile for the energy source. The controller704varies the intake and discharge rate thresholds as a function of this acquired, site specific data in order to maximize the efficiency of the overall system600. One skilled in the art will recognize that the controller704can be configured to instantly interrupt the method ofFIG. 12in response to the immediate energy requirement of the load602exceeding the power provided by the energy source604.

Referring toFIG. 13, a method of capturing energy provided by the energy source604in excess of the immediate energy requirement of the load602begins at1302. At1304, the controller704determines whether the energy provided by the energy source604exceeds the immediate energy requirement of the load602, and if not, the process ends at1306. If the energy provided by the energy source604exceeds the immediate energy requirement of the load602, then the controller704determines whether the first energy storage device608is available for capturing energy at1308. If the first energy storage device608is available, then the controller704determines whether the difference between the energy provided by the energy source604and the immediate energy requirement of the load602exceeds the intake rate threshold of the first energy storage device608at1310. If not, the controller704sends the appropriate signals to the energy converter702such that energy is captured in the first energy storage device608at1312and then proceeds back to1304. If the difference between the energy provided by the energy source604and the immediate energy requirement of the load602exceeds the intake rate threshold of the first energy storage device608at1310or the first energy storage device is not available at1308, then the controller704proceeds to determine whether the second energy storage device610is available at1314. If the second energy storage device610is not available, then the process ends at1306. If the second energy storage device610is available, then the controller704sends the appropriate signals to the energy converter702such that the second energy storage device610captures the energy provided by the energy source604in excess of immediate energy requirement of the load at1316, and the controller proceeds back to1304. One skilled in the art will recognize that the method ofFIG. 13can also be applied when discharging the energy storage device608,610in order to match the power output of the energy flow controller606to the immediate energy requirement of the load602. One skilled in the art will recognize that the controller704can be configured to instantly interrupt the method ofFIG. 13in response to the immediate energy requirement of the load602exceeding the power provided by the energy source604.

Referring toFIG. 14, a method of balancing the energy levels of the first and second energy storage devices608,610begins at1402. At1404, the controller704determines whether a predetermined time interval has passed. If the predetermined time interval has been reached, then at1406, the controller704sends the appropriate transfer signals to the energy converter702such that energy is transferred between the first energy storage device608and second energy storage device610until the first energy storage device reaches a first predetermined level, and the controller proceeds back to1402. If the predetermined time interval has not been reached, then the controller704proceeds to determine whether an energy level of any of the energy storage devices has reaches a maximum threshold or a minimum threshold at1408. If not, then the processor704proceeds back to1402. If so, at1410, the processor704sends the appropriate signals to the energy converter702such that energy is transferred from an energy storage device that has reached its maximum threshold or such that energy is transferred to an energy storage device that has reached its minimum threshold. The processor704ceases the energy transfer when the energy storage device that had reached its maximum or minimum threshold reaches a predetermined level of the energy storage device. In one embodiment, the predetermined levels associated with each energy storage device vary as a function of an expected energy requirement profile of the load and as a function of an expected energy output profile of the energy source. That is, information is collected about the load power requirements and energy source power output over a given time period are used to adapt the energy capture and extraction algorithms in order to maximize the efficiency of the overall system600, and the predetermined levels (i.e., first and second predetermined levels) are target states of charge (e.g., percent of capacity) for their respective energy storage devices.

Referring toFIG. 15, one example of a system1500stabilizes power provided from an energy source to a load. The system1500connects to a bus1502between the energy source and the load via a transformer1504. In this example, the energy source is a mix of gas turbine energy and wind energy wherein the mix of wind energy varies from 15 percent to 35 percent of the supplied energy and the load varies from about 85 MW to 210 MW in total. In this example, the energy requirement profile of the load is a 24 hour profile for each season, and the energy output profile of the energy source is also a 24 hour profile for each season. As discussed above, the energy profiles are used to determine variables within the system (e.g., minimum and maximum energy levels for each energy storage device, predetermined target energy levels for each energy storage device, etc.). In this system, almost 90% of the cycles are in the range of 2 to 4 MW/minute. The transformer1504is a 480Y/277V-22900Δ 2500 kVA transformer available from a number of commercial suppliers known to one skilled in the art. The bus1502is 22.9 kV at approximately 60 Hz.

The system1500includes a first sodium sulfur battery1506, a second sodium sulfur battery1508, a lithium ion battery1510, and a lead acid battery1512. The lithium ion battery1510accounts for 10% of the storage capacity of this system1500. The sodium sulfur batteries1506and1508account for 30% of the capacity of this system1500. The lead acid battery accounts for 60% of the capacity of this system1500. In this example, a system employing only lead acid batteries would have a 3-4 year life expectancy while this mix of storage devices provides a life expectancy of 10-15 years.

Each of the batteries has an associated direct current (DC) chopper1514,1516,1518, and1520and an associated charger1522,1524,1526, and1528. When the system1500is providing energy to the bus1502, the first and/or second DC choppers1514and1516regulate power from the first and/or second sodium sulfur batteries1506and1508to a first inverter1530. The first inverter1530converts the DC power from the first and/or second DC choppers1514and1516to an alternating current (AC) 480V signal at 60 Hz. A first filter1534removes any harmonic noise from the 60 Hz 480V signal and provides it to a first meter1538. The first meter1538monitors the flow of energy to and from the system1500to the bus1502to collect data for use in refining the algorithms determining which of the batteries to store energy in and provide energy from depending on other system conditions. Similarly, when the system1500is providing energy to the bus1502, the third and/or fourth DC choppers1518and1520regulate power from the lithium ion batter1510and/or the lead acid battery1512to the second inverter1532. The second inverter1532provides a 480V 60 Hz signal to the second harmonic filter1536which filters the signal for the second meter1540. The energy from the first and second meters1538and1540passes through the transformer1504to the bus1502.

When the system1500is storing energy from the bus1502, the first and/or second meters1538and1540receive power from the transformer1504and provide the power to any of the first, second, third, and/or fourth chargers1522,1524,1526, and1528. Each charger converts the received 480V 60 HZ power into DC power for its respective battery. One skilled in the art will recognize that the batteries1506,1508,1510, and1512may receive energy from their respective chargers1522,1524,1526, and1528at different voltages and store energy at different DC voltages. Further, the chargers may be set up to provide bulk charging and individual cell charging and equalization for cells within each of their respective batteries.

In another example, a system for stabilizing energy provided by a gas turbine based power plant to a load utilizes a mix of 10% lithium ion batteries, 30% sodium sulfur batteries, and 60% lead acid batteries. In this example, the energy requirement profile of the load is a 24 hour profile for each season. Although the gas turbines generators can operate at a near constant output level, and it is optimal to do so, the immediate energy requirement of the load varies. Thus, the power plant is required to vary the output level of the gas turbine generators while keeping diesel generators on standby for any power requirement variance beyond the capability of the operating gas turbine generators. In this example, the hybrid energy storage system enables the gas turbines to operate at optimal efficiency while reducing or eliminating the need for the power plant to keep diesel generators on standby which reduces emissions and costs of the power plant.

In another example, a portable system for stabilizing energy provided by a wind turbine includes a flywheel, lithium ion batteries, and lead acid batteries. In this example, the energy requirement profile of the load may be unknown due to the portable nature of the system while the energy output profile of the energy source (i.e., wind turbine or turbines) varies on a 24 hour cycle. In one embodiment, the system learns the 24 hour energy requirement profile of the load and adjusts the control variables to optimize the energy efficiency of the system. The wind turbine may be any turbine offered by, for example, Vestas Wind Systems or General Electric Company (e.g., the V47-660 kW from Vestas Wind Systems). In this example, the system is designed for maximum energy storage density and ease of use such that it is portable and can provide constant power to a small to moderate load using renewable energy. This system can replace or augment on site power generation currently provided by small internal combustion engine generators or diesel generators. The system may also utilize solar cells to provide power to the load.

In another example, a system includes one or more large wind turbines, such as those available from Vestas Wind Systems or General Electric Company (e.g., the General Electric 2.5 MW wind turbine or the V112-3.0 MW from Vestas Wind Systems) to provide power to a factory. A factory generally has a relatively constant power usage for given period of time while the wind turbines vary in their power output. For example, the system may use a 24 hour energy requirement profile for the load that does not change with the season while using a 24 hour energy profile for the wind turbines for each season. In this example, the hybrid energy storage system comprises a flywheel array and a lead acid battery array. The flywheels operate to respond to sharp differences between power provided by the wind turbines and power required by the factory while the lead acid battery array is used to provide power to the factory during periods of low wind. The system may also have input from a power plant or be able to utilize diesel generators at the factory in case a wind outage outlast the ability of the lead acid battery array to continuously provide the power required by the factory.

In one embodiment, a method of stabilizing power provided by an energy source to a load comprises determining an intake rate threshold of each of a first and second energy storage devices and a discharge rate threshold of each of the first and second energy storage devices as a function of at least one of: a type of the energy storage device, an initial capacity of the energy storage device, an characteristic internal resistance of the energy storage device, a chemical resistance of the energy storage device, an electrolyte of the energy storage device, a temperature of the energy storage device, a state of charge of the energy storage device, a capacity loss of the energy storage device, an intake efficiency of the energy storage device, and a discharge efficiency of the energy storage device.

In one embodiment, a method of stabilizing power provided by an energy source to a load comprises varying an intake rate threshold of a first energy storage device, an intake rate threshold of a second energy storage device, a discharge rate threshold of the first energy storage device, and a discharge rate threshold of the second energy storage device as a function of at least one of: a cooling capacity associated with the energy storage device, a heat dissipation coefficient of the energy storage device, an ambient air temperature profile, an energy requirement of the load, an cycle rate profile, and an energy production profile for the energy source.

In one embodiment, a method of stabilizing power provided by an energy source to a load comprises capturing energy in one of a first energy storage device a second energy storage device and a third energy storage device. The method further comprises capturing in a third energy storage device, energy produced by the energy source in excess of an immediate energy requirement of the load if an energy level of the second energy storage device is at a second maximum threshold. The first energy storage device comprises an array of lithium based electrochemical cells. The second energy storage device comprises at least one of an array of sodium sulfuric electrochemical cells and an array of nickel cadmium electrochemical cells. The third energy storage device comprises an array of lead acid electrochemical cells. The third energy storage device has a greater energy storage capacity than the second energy storage device. The second energy storage device has a greater energy storage capacity than the first energy storage device.

In one embodiment, a system for providing power to a load comprises an energy source, a first energy storage device, a second energy storage device, and an energy flow controller comprising a power monitor, a first energy level monitor, a second energy level monitor, an energy converter, and a controller. An intake rate threshold of each of the first and second energy storage devices and a discharge rate threshold of each of the first and second energy storage devices are determined by the energy flow controller as a function of at least one of: a type of the energy storage device, an initial capacity of the energy storage device, an characteristic internal resistance of the energy storage device, a chemical resistance of the energy storage device, an electrolyte of the energy storage device, a temperature of the energy storage device, a state of charge of the energy storage device, a capacity loss of the energy storage device, an intake efficiency of the energy storage device, and a discharge efficiency of the energy storage device.

In one embodiment, a system for providing power to a load comprises an energy source, a first energy storage device, a second energy storage device, and an energy flow controller comprising a power monitor, a first energy level monitor, a second energy level monitor, an energy converter, and a controller. The energy flow controller varies an intake rate threshold of the first energy storage device, an intake rate threshold of the second energy storage device, a discharge rate threshold of the first energy storage device, and a discharge rate threshold of the second energy storage device as a function of at least one of: a cooling capacity associated with the energy storage device, a heat dissipation coefficient of the energy storage device, an ambient air temperature profile, an energy requirement of the load, an cycle rate profile, and an energy production profile for the energy source.

In one embodiment, a system for providing power to a load comprises an energy source, a first energy storage device, a second energy storage device, and an energy flow controller comprising a power monitor, a first energy level monitor, a second energy level monitor, an energy converter, and a controller. The system further comprises a third energy storage device for selectively capturing power and selectively providing captured power. The first energy storage device comprises an array of lithium based electrochemical cells. The second energy storage device comprises at least one of an array of sodium sulfuric electrochemical cells and an array of nickel cadmium electrochemical cells. The third energy storage device comprises an array of lead acid electrochemical cells. The third energy storage device has a greater energy storage capacity than the second energy storage device, and the second energy storage device has a greater energy storage capacity than the first energy storage device.

Various principles of the disclosure have been described in illustrative embodiments. However, many combinations and modifications of the above described steps, formulations, proportions, elements, materials, and components used in the practice of the invention, in addition to those not specifically described, may be varied and particularly adapted to specific environments and operating requirements without departing from those principles. Other variations and modifications of the present disclosure will be apparent to those of ordinary skill in the art, and such variations and modifications are within the scope of the invention. More particularly, the methods illustrated inFIGS. 8-14may be used in any combination with one another.

Further, the description of various embodiments herein makes reference to the accompanying figures, which show embodiments of the invention by way of illustration and not of limitation. While these embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that logical, routine, or mechanical changes may be made without departing from the spirit and scope of the invention. Thus, the disclosure herein is presented for purposes of illustration only and not of limitation. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not limited to the order presented unless otherwise specified. Moreover, any of the functions or steps may be outsourced to or performed by one or more third parties. Furthermore, any reference to a singular component may include plural components, and any reference to more than one component may include a singular component.

One skilled in the art is familiar with conventional data networking, application development and traditional electrical circuits of the systems (and components of the individual operating components of the systems) described herein, such that a detailed description of these known components, applications, and networks is unnecessary herein. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system.

Additionally, functional blocks of the block diagrams and flowchart illustrations provided herein support combinations of means for performing the specified functions, combinations of steps for performing the specified functions, and program instruction means for performing the specified functions. It will also be understood that each functional block of the block diagrams and flowchart illustrations, and combinations of functional blocks in the block diagrams and flowchart illustrations, may be implemented by either special purpose hardware-based electronics and/or computer systems which perform the specified functions or steps, or suitable combinations of special purpose hardware and computer instructions.

Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the invention. The scope of the invention is accordingly to be limited by nothing other than the claims that may be included in an application that claims the benefit of the present application, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, and C” may be used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B, and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. Although certain embodiments may have been described as a method, it is contemplated that the method may be embodied as computer program instructions on a tangible computer-readable carrier and/or medium, such as a magnetic or optical memory or a magnetic or optical disk. All structural, chemical, and functional equivalents to the elements of the above-described embodiments that are known to those of ordinary skill in the art are contemplated within the scope of this disclosure.