CA2732592C - Smart bi-directional electric energy storage and multifunction power conversion system - Google Patents
Smart bi-directional electric energy storage and multifunction power conversion system Download PDFInfo
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- CA2732592C CA2732592C CA2732592A CA2732592A CA2732592C CA 2732592 C CA2732592 C CA 2732592C CA 2732592 A CA2732592 A CA 2732592A CA 2732592 A CA2732592 A CA 2732592A CA 2732592 C CA2732592 C CA 2732592C
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/28—Arrangements for balancing of the load in a network by storage of energy
- H02J3/32—Arrangements for balancing of the load in a network by storage of energy using batteries with converting means
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/388—Islanding, i.e. disconnection of local power supply from the network
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/40—Synchronising a generator for connection to a network or to another generator
- H02J3/42—Synchronising a generator for connection to a network or to another generator with automatic parallel connection when synchronisation is achieved
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/46—Controlling of the sharing of output between the generators, converters, or transformers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/20—The dispersed energy generation being of renewable origin
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E70/00—Other energy conversion or management systems reducing GHG emissions
- Y02E70/30—Systems combining energy storage with energy generation of non-fossil origin
Abstract
The disclosed invention represents an improved electrical energy storage system design and method of interconnecting it to an existing AC or DC electrical power distribution infrastructure that is used by consumers of electrical power. The invention represents a simplified method of installation over that commonly used by UPS and Grid Tie Inverters. The new energy storage system incorporates a number of new features and benefits to residential, commercial, industrial customers, electric utility and installer of renewable energy systems.
Description
SMART BI-DIRECTIONAL ELECTRIC ENERGY STORAGE AND MULTIFUNCTION
POWER CONVERSION SYSTEM
BACKGROUND OF THE INVENTION
The electric distribution grids in large parts of the developing world are unreliable and often use rolling blackouts to compensate for inadequate amounts of electric power to meet peak demands. Similar problems have been encountered in developed nations as demand for electric power exceeds the available electric generating capacity. Making the problem even more complex increasing amounts of the electric power generation is coming from renewable sources such as wind, solar, tidal and waves. These sources of electric power are intermittent and often do not provide power during the times of peak demand.
There are many solutions to the problem; the most common are the use of UPS
systems with , backup generators for homes or businesses that are hit by rolling blackouts and by adding electrical storage to the power distribution systems to provide the extra power when the generating capacity is inadequate. For those that have no electric grid access available to them there are few options with fossil fuel powered electric generators running inefficiently often used to provide power. It has been suggested to add electrical energy storage to renewable energy sources such that they appear as base load power rather than highly intermittent. However, installing renewable energy in residential homes is complex and expensive and in need of a simpler lower cost method of installation. Further suggestions have been to install energy storage in homes such that it powers homes during times of peak demand and recharges when available power exceeds demand. An alternative to home storage is to use electric cars, when they are plugged in to recharge, as a source of electric power that the electric utility can use when demand for electricity exceeds the available supply. Yet another area under development is the use of a smart grid where a utility can turn off low priority electrical equipment in the home or industry or to install special smart controllers that perform the task automatically during times of peak electrical usage.
All of these options appear as solutions to provide extra electric power when demand exceeds the available supply. The above solutions that store electrical energy and later on are capable of delivering the power to the grid, under direction of the electric utility, provide a method supplementing the available electric power when the demand exceeds the generating capacity.
However, these solutions intermix into the electric grid electric generation and customers when previously a generator was solely a provider of power and users only consumed it. This original arrangement simplified the electric grid such that simple fuses or switches could be used to disconnect, either 4 consumer of electric power or a generator from the electrical distribution system.
With a consumer being at times a supplier of electric power to the grid the simple system has been made complex such that it becomes difficult to isolate any single portion of the grid for service. In order to isolate a portion of the grid the utility would have to command all the individual home or industrial sources of electric power to shut off. However, the threat still remains that one or more systems fail to recognize the command to turn off, putting the service personnel at risk of injury ' through portions of the electric grid that are suppose to be inactive actually remaining actively powered.
Another major problem that all these smart devices represent is that they can appear as loads that can suddenly switch on or off and if there are enough of them they could destabilize the electric grid by suddenly adding or dropping the apparent load on the electric utility's distribution system.
DESCRIPTION OF PRIOR ART
Typical methods currently used as sub elements of the preferred embodiment are represented by the following list of documents.
U.S. PATENT DOCUMENTS
7,729,811 08/2006 Weir et al .. 700/295 2011/0013427 04/2010 Weir et al ..... 363/37 4,399,499 12/1981 Butcher et al .. 363/98 . 4,542,451 10/1983 David J. Hucker 363/132 8,085,557 07/2007 Hiroo Ito, Kariya et al .... 363/17 8,143,856 09/2009 Andrea et al .. 320/137 Published Documents Trowler, Derik et al., "Bi-Directional Inverter and Energy Storage System".
(May 2008), Thesis from University of Arkansas, College of Engineering, Department of Electrical Engineering, submitted to fulfill the requirements of: Texas Instruments 2008 Analog Design Contest, won first prize.
Residential energy storage systems have become the major area of technological development. In reality what is called the residential energy storage system is in fact a type of Bi-Directional Electrical Energy Storage and Multifunction Power Conversion System with each system containing electrical energy storage such as batteries, the power processing section that functions the same as the bi-directional DC to AC Inverter that uses the microprocessor type of . system controller and the external interface. Improvements and new developments to the basic type of overall ,system are occurring at the ever increasing rate. The areas of improvements are to the energy storage device, the bi-directional DC to AC inverter design, the type and methods of overall system control, user interface and method of overall operation.
The above list of US Patent documents provide a good representation of the evolution of these individual elements. Patent 4,399,499 represents an early type of bi-direction universal 4 quadrant power converter. This technology is capable of converting any type of DC or AC into another voltage level DC or AC signal. This patent application uses the early introduction of digital synthesis of the AC signal using a lookup table. Patent 8,085,557 represents the much later version of bi-directional DC-AC inverter technology.
The document "Bi-Directional Inverter and Energy Storage System". (May 2008), is a modern representation of the residential electrical energy storage system design that provides useful functions for supporting the electric grid during periods of peak demand and supports time of day storage of renewable energy. This example uses what is called a DSP which stands for Digital Signal Processor a specialized type of microprocessor that is optimized for the control electrical power processing circuits. One major advantage of using a DSP is that it can multiply the line current and line voltage measurements together to give the electrical power that is consumed.
UPS systems lack the more complex capabilities required by customers that have to pay for electric power not only by the amount that they use but in addition to the time of day that they use it.
The development of Smart Energy Storage Systems is very new and most competing Art remains in the confidential phase of their filing.
SUMMARY OF THE INVENTION
The purpose of the invention is to provide an improved Smart Energy Storage System for use by consumers of electrical energy to reduce their cost of electric power, if they are charged by time of use.
Another purpose of the invention is to improve the stability of a Utility's electric grid with additional features and capabilities to reduce the cost of installation of renewable energy sources.
The preferred embodiment of the invention consists of at least one electrical current monitor that measures the magnitude and phase of the current being drawn from the utility, a Bi-Directional Inverter, an Energy Storage device and a digitally based System Controller.
A variation of the preferred embodiment has added to it an External Communications Module used by the System Controller to communicate with the operator of the system.
Another variation of this preferred embodiment has the External Communication Module controlled by the Utility such that it can charge or discharge the consumer's Energy Storage at a time of its choice.
A further variation of this preferred embodiment has the External Communication Module controlled by a third party such that it can charge or discharge the consumer's Energy Storage at a time of their choice such that it can store power in the Energy Storage when it is inexpensive and resell it to the Utility of other customer when it is expensive.
Another variation of this preferred embodiment has the External Communication Module controlled by the customer such that it can charge their Energy Storage at a time when electric power from the Utility is inexpensive and to operate from the Energy Storage when electric power from the Utility is expensive.
A further preferred embodiment uses the System Controller through the External Communications Module to turn on or off smart electrical devices in order to increase or decrease the apparent load seen by the Utility's electrical grid.
A further variation of the preferred embodiment has added to it a Renewable Power Converter that is used to charge the Energy Storage device from a renewable energy source.
Another variation of this preferred embodiment has the Renewable Power Converter deliver the power directly from a renewable energy source to the Bi-Directional Inverter for use by the consumer, sale to the electric utility or other customer. With yet another variation of this preferred embodiment has the addition of a electrical power meter to measure the net power produced for sale or self use from a renewable energy source.
A further variation of the preferred embodiment has added the ability to control, synchronize with and transfer the power from an external electrical generation system to the main consumer electrical power distribution system. Another variation of this preferred embodiment has the addition of an electrical power meter to measure the net power produced for sale or self-use from an external electrical generator.
A variation of the preferred embodiment has added to it the ability to make the consumers load to the Electric Utility as a constant slowly changing load. Another variation of this preferred embodiment has the ability to deliver power to or absorb power from the Utility electrical grid when the voltage is extremely low or high respectively.
Yet another variation of this preferred embodiment has added to it an external power relay that when de-energized isolates the consumer from the Utility electric grid allowing the Smart Energy Storage System to power the consumer independently of the state of the Utility's electric grid. Another variation of this preferred embodiment has the inclusion of an external electric switch allowing the Utility the option to disconnect the consumer from its electric grid using the switch.
A further variation of this preferred embodiment has the System Controller monitor the Utility electric grid voltage and when it is abnormally low the System Controller removes energy from the Energy Storage to decrease the consumer's apparent load to the Utility and if the electric grid voltage is abnormally high charge the Energy Storage in accordance with rules set up the responsible legal body such as the utility or government.
Yet another variation of this preferred embodiment has the Smart Energy Storage System connected to a DC electrical power system rather than an AC one while retaining all the same functionality and options available to the AC version.
In another embodiment of the invention the electric power from the Utility is fed directly into the Smart Energy Storage System and all the associated external switches and meters are also located inside and are part of the system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a logic flow without being externally controlled of the control of the preferred embodiment;
FIG. 2 represents a block diagram of the main functional elements of the preferred embodiment;
FIG. 3 represents various output load or demand profiles that can be created using the preferred embodiment;
FIG. 4 depicts a logic flow with the preferred embodiment under external control;
DETAILED DESCRIPTION OF THE INVENTION
The embodiment in FIGURE 2 in accordance with the present invention is intended to represent a common method of installation and use of the preferred embodiment of the invention.
The blocks that are within the outlined area 218 and including the external current monitor 201 represent the preferred embodiment of the Smart Bi-Directional Electrical Energy System which is abbreviated as Smart Energy Storage System and on occasion referred to as System though the later term should not be confused with item 209 in FIGURE 2 which is the System Controller. In FIGURE 2, 205 represents the external connection point to the electric utility, which may deliver power to its customer using single phase, 2 phase, 3 phase or more phases AC
or in special circumstances DC. The standard voltage and frequency of the electrical power is established by the electric utility.
In FIGURE 2, 204 represents a mechanical disconnect used on most systems with the location and type of the disconnect set by the utility. This electrical disconnect is used to remove the customer from the electric power distribution system in order for workers to safely service or make changes to the customer's electric distribution system. Figure 2, 206 is the power meter used by the utility for the purpose of recording the power consumed by its customers. The meter can be either an old style mechanical or a new electronic type, which adds newer features for the utility. In the preferred embodiment FIGURE 2, the power meter 206, is connected to the Smart Energy Storage System allowing the collection of the data for the utility and transmission of the information through the Smart Energy Storage System's own communication with the electric utility.
Figure 2, 202 represents a disconnect device, such as a high power relay, that is used to disconnect the user from the utility if their power distribution system should fail, upon which occurrence the customer would operate using energy from the Energy Storage 214 and the operation of the power relay would be controlled by the System Controller 217. Figure 2, 203 represents an external switch that when open disconnects the customer from the utility's electric distribution system by interrupting the power relay 202 drive voltage. The switch 203 can be used as a replacement in some circumstances for the disconnect switch 204.
In FIGURE 2, 201 represents a current monitor used by the Smart Energy Storage System to measure the magnitude and phase of the electrical current used by the customer with a separate unit installed on each input line of the power supplied by the utility. The current monitor 201 can be any type such as amplified current-shunt, current transformer, solid-state transformer etc. and the signal can be shared by more than one Smart Energy Storage System. At least one electrical signal from the current monitor 201, representing the magnitude and phase of the current on each input line, is supplied as input to the System Controller 217 of the Smart Energy Storage System. In another embodiment of the preferred embodiment of the invention the electrical power 205 from the utility is fed completely through the Smart Energy Storage System and items 206, 202 and 201 are all located inside one or more boxes that together represent the Smart Energy Storage System.
Most embodiments of the invention represented by FIGURE 2 contain at least one System Controller 217, an External Communications Module 216, an Energy Storage module 214 and a Bi-Directional Inverter 211. The Bi-Directional Inverter 211 is substituted with a Bi-directional DC to DC converter when the customer's power system is DC rather than the more common AC.
Furthermore, the Energy Storage 214 can be but is not limited to any type of energy storage such as ultracapacitor, battery, fly-wheel, pumped-hydro, compressed-air which can be interfaced with the customers electric power distribution system through a suitable Bi-directional power conversion process represent jly 211. The System Controller 217 contains at least one digital processing circuit that controls at a minimum the function of charge and discharge of the Energy Storage 214 through the Bi-direction Inverter 211 to the customer's electrical distribution system represented by 220.
In FIGURE 2 the preferred embodiment the System Controller 217 is a much more complex operating system containing multiple digital processors inter communicating with each other and the various elements of the Smart Energy Storage System. It is able to communicate through the External Communications Module 216 with various external devices such as but not limited to user power monitors, the electric utility and various other electrical consuming or generating devices connected to the customer's electrical distribution system. The External Communication Module 216 communicates with these external devices through port 215, which represents at least one external communication interface. This interface may be wireless bi-directional or wireless single directional communication and in combination with, or alternately through optical or electrical cables. The System Controller 217 controls the integration of the Renewable Power Converter 213 which is a common option used to interface electrical power generated by the customer connected through the external electrical connection 212, from but not limited to renewable sources such as solar, wind geothermal wave, tidal etc. to the customers electrical power system. For small installations such as those used by a home or residence the inclusion of this option greatly reduces the cost and time needed to install renewable energy sources such as wind or solar to the electrical grid. The installer only has to connect the external renewable power through input 212, add the Renewable Converter Module 213 to the Smart Energy Storage System and enable or install the upgraded software in the System Controller 217. For added convenience an electrical power meter 209 can be added to the Smart Energy Storage System in order to enable the recording of the amount of net renewable energy generated by the customer for their own use or sale to the electric utility with the net metered amount computed and made available to the utility either via communication or visual readout by the System Controller 217. The power meter 209 determines the net excess power generated by the Smart Energy Storage System by recording the net power that flows into and out of the Bi-direction Inverter 211 with any surplus power representing the power generated by the renewable power source connected at 212. The electrical power meter 209 can be relocated such that it is able to include the energy generated by an external electrical generator in additional to any other external power source as desired. The System Controller 217 operates a number of other elements such as but not limited to 207 an External Electric Generator used to either generate electric power continuously for use by the customer or in other embodiments it acts as an emergency electrical power source to replace the electric power from the utility that may have been interrupted., When the External Electric Generator 207 is first started its output power is disconnected from the Customer's Electrical System 220 by power relay 208, which may be mechanical or solid-state until the External Electric Generator's 207 output has reached suitable magnitude and phase to be connected to the customers electrical power distribution system 220.
When the External Electric Generator 207 is operating the Energy Storage 214 can be recharged and if the capacity of the Bi-Directional Inverter is adequate the External Electric Generator 207 can be operated at its most efficient point until the Energy Storage 214 is fully charged and then it can be shut off and the Customer's Electrical System 220 operated with stored electric power until the Energy Storage 214 is discharged to a preset minimum level at which point it can be restarted. The Power Relay 210 can be operated at any time by the System Controller 217 to disconnect the Bi-Directional Inverter 211 from the external electric generator. Operating the External Electric Generator 207 only when it is needed to recharge Energy Storage 214 saves both the operational life of the External Electrical Generator 207 but fuel as it can be operated at the point of its highest efficiency.
FIGURE 3 represents a major capability of the System Controller (FIGURE 2, 217) of the preferred embodiment of the disclosed invention. In FIGURE 3, 333 represents TO through T12 that are random time intervals when the customer's electric power usage changes.
Electric Utilities prefer customer loads that gradually increase or decrease because the electrical generating equipment can only increase or decrease the amount of available power on the electrical grid slowly.
To satisfy immediate electrical demand increases Electric Utilities must keep an amount of reserve generating power available to instantaneously provide the power from the surplus generating capacity consuming fuel without producing electrical power sales. The ideal system would be one where the Electric Utility is able to either immediately increase or decrease the amount of load on the electric grid in order to reduce the amount of surplus generating capacity it must keep on hot standby. Ideally the load control should be able to handle changes in the electrical demand instantaneously. The Smart Energy Storage System is designed specifically with that capability.
FIGURE 3 represents a number of different graphs of power consumption. Figure 3, 331 is the ideal customer from the Electric Utility's point of view, continuous unchanging load, easy to predict and provide power for. Figure 3, 332 is what the Electric Utility would see from a customer that generates part of its power from a renewable source and deliveries it through the electric grid and when they don't produce a surplus they draw electrical power from the electric grid. If the Electric Utility cannot have a customer that appears, as 331 then its next choice would be a customer that sells or uses power represented by the line 330. In line 330 the power supplied or used changes over a period of time not instantaneously allowing the Electric Utility to increase or decrease the amount of power it produces. Currently, all of the Electric Utility customer's deliver or use power like the curve represented by 332. This is not a major problem for Electric Utilities so long as it has a large number of customers and the changes in power consumption occur on a random basis. This is nearly true except that during the day there are times that the power demand peaks.
These time of the day events are consistent and currently Electric Utilities are able to predict the demand versus time of day with reasonable accuracy. However, this situation may be about to change with the use of net metering and smart home controllers that are designed to turn off loads during those times when electric power is expensive. The smart controllers will all respond to a common set of information turning on and off smart appliances in order to save customer's money. The problem is that consumers will no longer be an aggregate of random changes in electric power demand but will represent very large loads suddenly applied to the electric grid when the price for electric power is inexpensive and disconnected from the electric grid when the price is high.
This is the worse possible scenario for the Electric Utility, having a significant number of its customers synchronized so they in mass increase or decrease their demand. The preferred embodiment of the disclosed invention represented by FIGURE 2 is capable of providing to the Electric Utility a load such represented by 331 in FIGURE 3 or at worse a slowly changing load like 330. To achieve the customer load profile represented by 331 the System Controller 217 (all remaining references in this paragraph will be from FIGURES 2 or 3) will monitor the magnitude and phase of load current 201 in conjunction with the line voltage to calculate the power that the customer is drawing from the Electric Utility at 205. The System Controller 217 will then either delivery more power to the customer's local electric grid 220 or draw power from it by using the Bi-Direction Inverter in conjunction with the Energy Storage 214 in such magnitudes that the load to the Electric Utility appears to remain constant. The System Controller 217 has the additional capability to turn on or off the customer's smart electric loads through the External Communications Module 216 if the Bi-Directional Inverter 211 is not able to deliver or consume enough electrical power. If the size of the Energy Storage 214 or the capability of the B-Direction Inverter 211 is not adequate then the System Controller 217 can filter out the power increase or decreases over a time interval that matches the ability of the Electric Utility to increase or decrease the amount of electric power it generates. The System Controller 217 can also change the way that the electric power from the customers' renewable energy sources is delivered to the electric grid, by delivering it at another time of day.
The System Controller 217 monitors the customer's daily power usage and adjust the level of energy held by the Energy Storage 214 as needed to maintain its ability to supply energy from or to store energy to it.
It should be obvious to those that are experts in the state of the art of designing charging systems that electric vehicle chargers can represent a similar sudden increase or decrease in demand to the electric utilities. For example most workers either start work at a specific time or leave work at the same time. Plugging in or disconnecting electric vehicle chargers at those times would represent a simultaneous increase or decrease in electric power demand. Large parking lots will either need a Smart Energy Storage System to supplement the charging systems or use the gradual increase and decrease in electrical demand as a built in function of the chargers. Another solution is to use external communication with the utility to set the rate of charging, however even then it is preferred to use a preset rate of charger load increase when starting or decrease, when charging is completed to save the utility the complex task of processing potentially millions of smart electric devices in real time. At home the Smart Energy Storage System's Energy Storage 214 can be made large enough that it can provide the power to quickly recharge an electric car. It therefore follows logically that proposed fast recharge stations for electric cars will have to use large Smart Energy Storage Systems in order to be able to purchase electric power when it is inexpensive to recharge cars during the time of day when the demand for electric power is the highest.
These large fast recharge stations for electric cars would represent a very large amount of online Electric Grid Storage and could easily serve as a active electric Grid Storage systems used to help stabilize the Electric Utility's electric power network.
There are a number of other ways that the Smart Energy Storage System can be controlled, however most of them will require approval from and follow the guidelines set by the Electric Utility, with a few of the more common ones being:
i. The System Controller 217 FIGURE 2 monitors the Electric Utility's line voltage and during times when the line voltage is either abnormally low or in brownout the customer's load can be significantly decreased reducing the demand for electric power or delivering power to the electric grid.
ii. The System Controller 217 FIGURE 2 monitors the Electric Utility's line voltage and during times when the line voltage is either abnormally high or excessively peaking the customer's load can be significantly increased or the Energy Storage 214 charged increasing the demand for electric power helping to absorb the excess generating capacity.
iii. The Electric Utility directly controls, through the External Communications Module 216, the Smart Energy Storage System to change the amount of electric power the customer appears to be using or delivering power to the electric grid. In this way the Electric Utility has the ability to decrease demand during times when the amount electric power generation is inadequate or to increase demand by charging the Energy Storage 214 when there is a surplus of electric power available.
iv. Another method of control is by another company that directly controls, through the External Communications Module 216, the magnitude of the how much electric energy the Smart Energy Storage System either makes the customer appear to be using or even delivering to the electric grid. In this way the company can sell electric power into the electric grid when the price is high and recharge the Energy Storage 214 when the price for electric power is low.
The company would pay the customer for use of its Smart Energy Storage System.
v. Yet another method of control is that the System Controller 217 receives the time of use cost for electric power, through the External Communications Module 216, and then alters the magnitude of how much electric energy the Smart Energy Storage System makes the customer appear to be using. In this way the customer uses electric power from the Energy Storage 214 when the price is high and recharges the Energy Storage 214 when the price for electric power is low. The customer in this way reduces the magnitude of its electric power bill by using its Smart Energy Storage System.
vi. One other way the Smart Energy Storage System can be used is to store and provide electric power in those parts of the world that either don't have a reliable electric grid or none at all.
When there is no electric grid then an external power source such as electric generator or renewable energy source can be used to charge the Energy Storage 214. If there is an electric grid that is unreliable the customer can use the Smart Energy Storage System to store their own renewable energy and operate it as a UPS providing electric power when there is none available and storing surplus electric power for later use when it is available. Under these circumstances the System Controller 217 communicates with and controls the external power generating systems.
FIGURE 1 represents the process control used by the Smart Energy Storage System of the preferred embodiment when there is no external communications control, but connected to a reliable electric grid. FIGURE 1 represents the most basic of the functional control loops with a number of major changes possible depending on a number of external factors, described in detail in previous sections of the description of the preferred embodiment, that the Smart Energy Storage System is programmed to control. When the Smart Energy Storage System is turned on at START 100 it goes through a number of self check processes, not shown and then LOADS PRESETS 101 that the system must comply with. These presets may be defined by the utility, for the customer's safety or how the system is configured i.e. off the electric grid with an electric generator and solar electric power etc.. The Smart Energy Storage System then proceeds to 102 CHARGE TO
MINIMAL
LEVEL its Energy Storage 214, FIGURE 2 to the energy level that the system presets defines as minimally functional. Upon reaching that level the Smart Energy Storage System enters into its main function loop. It constantly monitors the electric grid voltage at LINE
VOLTAGE OK 103 &
107 and if line voltage is not adequate the Smart Energy Storage System will stop charging or discharging and the loop returns to the main entry point at LINE VOLTAGE
MONITOR 103. If the = line voltage at LINE VOLTAGE OK 103 is acceptable then it checks if it is the TIME OF DAY TO
CHARGE 104 if it is then proceed to 105 RECHARGE and if not then skip recharging and proceeds to TIME OF DAY TO DISCHARGE 106 and if its is the time for the user to run off of energy storage it then checks to see if the line voltage is acceptable at LINE
VOLTAGE OK 107. This check reflects one method the Utility uses to automatically over ride the time of day to run from storage operation. LINE VOLTAGE OK 107 generates NO condition if the line voltage is excessively high then returns to 103 aborting the decision to OPERATE FROM
STORAGE 108.
This is the indication from the Utility that there is a surplus of power in the grid. If the LINE
VOLTAGE OK 107 is nominal or low then the Smart Energy Storage System proceeds to 108 OPERATE FROM STORAGE. It then delivers the amount of electric power required by the customer from Energy Storage 214, FIGURE 2 in the manner it has been programmed to do so and while it is doing this it loops back to the start LINE VOLTAGE OK 103 to repeat the whole decision process.
= FIGURE 4 represents the process control used by the Smart Energy Storage System of the preferred embodiment when there is external communications control and connected to a reliable electric grid. FIGURE 4 represents the most basic of the externally controlled functional control loops with a number of major changes possible depending on a number of external factors, described in detail in previous sections of the description of the preferred embodiment, that the Smart Energy Storage System is programmed to control. When the Smart Energy Storage System is turned on at START 400 it goes through a number of self check processes, not shown and then LOADS PRESETS 401 that the system must comply with. These presets may be defined by the utility, for the customer's safety or how the system is configured i.e. off the electric grid with an electric generator and solar electric power etc.. Then the Smart Energy Storage System attempts to initiate at START EXTERNAL COM. 402 external communications. If it is successful it proceeds through SUCCESS to 403 LINE VOLTAGE OK. If instead it FAILED it loops through a preset , , time DELAY 409 then to TIMED OUT 410. If TIMED OUT 410 is NO it returns to START
EXTERNAL COM. 402 however if it is YES the Smart Energy Storage System will set the SYSTEM FAULT ALARM 411then return back to 402 START EXTERNAL COM where it continues to try to establish external communications. In many embodiments a limited form of the system operation will take place until proper communications are established.
If external communications is successfully established at START EXTERNAL COM. 402 then The Smart Energy Storage System often proceeds to CHARGE TO MINIMAL LEVEL, not shown, its Energy Storage 214, FIGURE 2 to the energy level that the system presets defines as minimally functional.
Upon reaching that level the Smart Energy Storage System enters into its main function loop. It constantly monitors the electric grid voltage at LINE VOLTAGE OK 403 & 407 and if line voltage is not adequate the Smart Energy Storage System will stop charging or discharging and the loop returns to the main entry point at LINE VOLTAGE MONITOR 403 in addition it continuously checks, not shown, that the external communications is active. If the line voltage at LINE
. VOLTAGE OK 403 is acceptable then it checks if it is the COMMAND TO
RECHARGE 404 has been given where if it is YES proceeds to RECHARGE 405 then 406 COMMAND TO
DISCHARGE and if NO it skips recharging and proceeds to COMMAND TO DISCHARGE
406.
At COMMAND TO DISCHARGE 406 the Smart Energy Storage System generates a NO if it isn't commanded to do so then returns to Line VOLTAGE OK 403. If COMMAND TO
DISCHARGE
406 is YES it proceeds to see if the line voltage is acceptable at LINE
VOLTAGE OK 407 where it is NO it returns to LINE VOLTAGE OK 403. If LINE VOLTAGE OK 407 is YES then the Smart Energy Storage System delivers the amount of electric power to the customer from Energy Storage 214, FIGURE 2 in the manner it has been externally commanded to do so at OPERATE FROM
STORAGE 408 and while it is doing this it loops back to the start LINE VOLTAGE
OK 403 to repeat the whole decision process.
To comply with the utility anti-islanding regulations during all modes of operation the Smart Energy Storage System closely monitors the utility's line voltage and frequency to determine if the utility has disconnected power from the customer at which point it will either switch to UPS
mode or shut down.
It is well known by one skilled in the art that many applications involving the change to the invention's operation based on the voltage of the external AC power source often involve the same change based on the change to the line frequency of said power source.
Although the invention has been described in connection with a preferred embodiment, it should be understood that various modifications, additions and alterations may be made to the invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
POWER CONVERSION SYSTEM
BACKGROUND OF THE INVENTION
The electric distribution grids in large parts of the developing world are unreliable and often use rolling blackouts to compensate for inadequate amounts of electric power to meet peak demands. Similar problems have been encountered in developed nations as demand for electric power exceeds the available electric generating capacity. Making the problem even more complex increasing amounts of the electric power generation is coming from renewable sources such as wind, solar, tidal and waves. These sources of electric power are intermittent and often do not provide power during the times of peak demand.
There are many solutions to the problem; the most common are the use of UPS
systems with , backup generators for homes or businesses that are hit by rolling blackouts and by adding electrical storage to the power distribution systems to provide the extra power when the generating capacity is inadequate. For those that have no electric grid access available to them there are few options with fossil fuel powered electric generators running inefficiently often used to provide power. It has been suggested to add electrical energy storage to renewable energy sources such that they appear as base load power rather than highly intermittent. However, installing renewable energy in residential homes is complex and expensive and in need of a simpler lower cost method of installation. Further suggestions have been to install energy storage in homes such that it powers homes during times of peak demand and recharges when available power exceeds demand. An alternative to home storage is to use electric cars, when they are plugged in to recharge, as a source of electric power that the electric utility can use when demand for electricity exceeds the available supply. Yet another area under development is the use of a smart grid where a utility can turn off low priority electrical equipment in the home or industry or to install special smart controllers that perform the task automatically during times of peak electrical usage.
All of these options appear as solutions to provide extra electric power when demand exceeds the available supply. The above solutions that store electrical energy and later on are capable of delivering the power to the grid, under direction of the electric utility, provide a method supplementing the available electric power when the demand exceeds the generating capacity.
However, these solutions intermix into the electric grid electric generation and customers when previously a generator was solely a provider of power and users only consumed it. This original arrangement simplified the electric grid such that simple fuses or switches could be used to disconnect, either 4 consumer of electric power or a generator from the electrical distribution system.
With a consumer being at times a supplier of electric power to the grid the simple system has been made complex such that it becomes difficult to isolate any single portion of the grid for service. In order to isolate a portion of the grid the utility would have to command all the individual home or industrial sources of electric power to shut off. However, the threat still remains that one or more systems fail to recognize the command to turn off, putting the service personnel at risk of injury ' through portions of the electric grid that are suppose to be inactive actually remaining actively powered.
Another major problem that all these smart devices represent is that they can appear as loads that can suddenly switch on or off and if there are enough of them they could destabilize the electric grid by suddenly adding or dropping the apparent load on the electric utility's distribution system.
DESCRIPTION OF PRIOR ART
Typical methods currently used as sub elements of the preferred embodiment are represented by the following list of documents.
U.S. PATENT DOCUMENTS
7,729,811 08/2006 Weir et al .. 700/295 2011/0013427 04/2010 Weir et al ..... 363/37 4,399,499 12/1981 Butcher et al .. 363/98 . 4,542,451 10/1983 David J. Hucker 363/132 8,085,557 07/2007 Hiroo Ito, Kariya et al .... 363/17 8,143,856 09/2009 Andrea et al .. 320/137 Published Documents Trowler, Derik et al., "Bi-Directional Inverter and Energy Storage System".
(May 2008), Thesis from University of Arkansas, College of Engineering, Department of Electrical Engineering, submitted to fulfill the requirements of: Texas Instruments 2008 Analog Design Contest, won first prize.
Residential energy storage systems have become the major area of technological development. In reality what is called the residential energy storage system is in fact a type of Bi-Directional Electrical Energy Storage and Multifunction Power Conversion System with each system containing electrical energy storage such as batteries, the power processing section that functions the same as the bi-directional DC to AC Inverter that uses the microprocessor type of . system controller and the external interface. Improvements and new developments to the basic type of overall ,system are occurring at the ever increasing rate. The areas of improvements are to the energy storage device, the bi-directional DC to AC inverter design, the type and methods of overall system control, user interface and method of overall operation.
The above list of US Patent documents provide a good representation of the evolution of these individual elements. Patent 4,399,499 represents an early type of bi-direction universal 4 quadrant power converter. This technology is capable of converting any type of DC or AC into another voltage level DC or AC signal. This patent application uses the early introduction of digital synthesis of the AC signal using a lookup table. Patent 8,085,557 represents the much later version of bi-directional DC-AC inverter technology.
The document "Bi-Directional Inverter and Energy Storage System". (May 2008), is a modern representation of the residential electrical energy storage system design that provides useful functions for supporting the electric grid during periods of peak demand and supports time of day storage of renewable energy. This example uses what is called a DSP which stands for Digital Signal Processor a specialized type of microprocessor that is optimized for the control electrical power processing circuits. One major advantage of using a DSP is that it can multiply the line current and line voltage measurements together to give the electrical power that is consumed.
UPS systems lack the more complex capabilities required by customers that have to pay for electric power not only by the amount that they use but in addition to the time of day that they use it.
The development of Smart Energy Storage Systems is very new and most competing Art remains in the confidential phase of their filing.
SUMMARY OF THE INVENTION
The purpose of the invention is to provide an improved Smart Energy Storage System for use by consumers of electrical energy to reduce their cost of electric power, if they are charged by time of use.
Another purpose of the invention is to improve the stability of a Utility's electric grid with additional features and capabilities to reduce the cost of installation of renewable energy sources.
The preferred embodiment of the invention consists of at least one electrical current monitor that measures the magnitude and phase of the current being drawn from the utility, a Bi-Directional Inverter, an Energy Storage device and a digitally based System Controller.
A variation of the preferred embodiment has added to it an External Communications Module used by the System Controller to communicate with the operator of the system.
Another variation of this preferred embodiment has the External Communication Module controlled by the Utility such that it can charge or discharge the consumer's Energy Storage at a time of its choice.
A further variation of this preferred embodiment has the External Communication Module controlled by a third party such that it can charge or discharge the consumer's Energy Storage at a time of their choice such that it can store power in the Energy Storage when it is inexpensive and resell it to the Utility of other customer when it is expensive.
Another variation of this preferred embodiment has the External Communication Module controlled by the customer such that it can charge their Energy Storage at a time when electric power from the Utility is inexpensive and to operate from the Energy Storage when electric power from the Utility is expensive.
A further preferred embodiment uses the System Controller through the External Communications Module to turn on or off smart electrical devices in order to increase or decrease the apparent load seen by the Utility's electrical grid.
A further variation of the preferred embodiment has added to it a Renewable Power Converter that is used to charge the Energy Storage device from a renewable energy source.
Another variation of this preferred embodiment has the Renewable Power Converter deliver the power directly from a renewable energy source to the Bi-Directional Inverter for use by the consumer, sale to the electric utility or other customer. With yet another variation of this preferred embodiment has the addition of a electrical power meter to measure the net power produced for sale or self use from a renewable energy source.
A further variation of the preferred embodiment has added the ability to control, synchronize with and transfer the power from an external electrical generation system to the main consumer electrical power distribution system. Another variation of this preferred embodiment has the addition of an electrical power meter to measure the net power produced for sale or self-use from an external electrical generator.
A variation of the preferred embodiment has added to it the ability to make the consumers load to the Electric Utility as a constant slowly changing load. Another variation of this preferred embodiment has the ability to deliver power to or absorb power from the Utility electrical grid when the voltage is extremely low or high respectively.
Yet another variation of this preferred embodiment has added to it an external power relay that when de-energized isolates the consumer from the Utility electric grid allowing the Smart Energy Storage System to power the consumer independently of the state of the Utility's electric grid. Another variation of this preferred embodiment has the inclusion of an external electric switch allowing the Utility the option to disconnect the consumer from its electric grid using the switch.
A further variation of this preferred embodiment has the System Controller monitor the Utility electric grid voltage and when it is abnormally low the System Controller removes energy from the Energy Storage to decrease the consumer's apparent load to the Utility and if the electric grid voltage is abnormally high charge the Energy Storage in accordance with rules set up the responsible legal body such as the utility or government.
Yet another variation of this preferred embodiment has the Smart Energy Storage System connected to a DC electrical power system rather than an AC one while retaining all the same functionality and options available to the AC version.
In another embodiment of the invention the electric power from the Utility is fed directly into the Smart Energy Storage System and all the associated external switches and meters are also located inside and are part of the system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts a logic flow without being externally controlled of the control of the preferred embodiment;
FIG. 2 represents a block diagram of the main functional elements of the preferred embodiment;
FIG. 3 represents various output load or demand profiles that can be created using the preferred embodiment;
FIG. 4 depicts a logic flow with the preferred embodiment under external control;
DETAILED DESCRIPTION OF THE INVENTION
The embodiment in FIGURE 2 in accordance with the present invention is intended to represent a common method of installation and use of the preferred embodiment of the invention.
The blocks that are within the outlined area 218 and including the external current monitor 201 represent the preferred embodiment of the Smart Bi-Directional Electrical Energy System which is abbreviated as Smart Energy Storage System and on occasion referred to as System though the later term should not be confused with item 209 in FIGURE 2 which is the System Controller. In FIGURE 2, 205 represents the external connection point to the electric utility, which may deliver power to its customer using single phase, 2 phase, 3 phase or more phases AC
or in special circumstances DC. The standard voltage and frequency of the electrical power is established by the electric utility.
In FIGURE 2, 204 represents a mechanical disconnect used on most systems with the location and type of the disconnect set by the utility. This electrical disconnect is used to remove the customer from the electric power distribution system in order for workers to safely service or make changes to the customer's electric distribution system. Figure 2, 206 is the power meter used by the utility for the purpose of recording the power consumed by its customers. The meter can be either an old style mechanical or a new electronic type, which adds newer features for the utility. In the preferred embodiment FIGURE 2, the power meter 206, is connected to the Smart Energy Storage System allowing the collection of the data for the utility and transmission of the information through the Smart Energy Storage System's own communication with the electric utility.
Figure 2, 202 represents a disconnect device, such as a high power relay, that is used to disconnect the user from the utility if their power distribution system should fail, upon which occurrence the customer would operate using energy from the Energy Storage 214 and the operation of the power relay would be controlled by the System Controller 217. Figure 2, 203 represents an external switch that when open disconnects the customer from the utility's electric distribution system by interrupting the power relay 202 drive voltage. The switch 203 can be used as a replacement in some circumstances for the disconnect switch 204.
In FIGURE 2, 201 represents a current monitor used by the Smart Energy Storage System to measure the magnitude and phase of the electrical current used by the customer with a separate unit installed on each input line of the power supplied by the utility. The current monitor 201 can be any type such as amplified current-shunt, current transformer, solid-state transformer etc. and the signal can be shared by more than one Smart Energy Storage System. At least one electrical signal from the current monitor 201, representing the magnitude and phase of the current on each input line, is supplied as input to the System Controller 217 of the Smart Energy Storage System. In another embodiment of the preferred embodiment of the invention the electrical power 205 from the utility is fed completely through the Smart Energy Storage System and items 206, 202 and 201 are all located inside one or more boxes that together represent the Smart Energy Storage System.
Most embodiments of the invention represented by FIGURE 2 contain at least one System Controller 217, an External Communications Module 216, an Energy Storage module 214 and a Bi-Directional Inverter 211. The Bi-Directional Inverter 211 is substituted with a Bi-directional DC to DC converter when the customer's power system is DC rather than the more common AC.
Furthermore, the Energy Storage 214 can be but is not limited to any type of energy storage such as ultracapacitor, battery, fly-wheel, pumped-hydro, compressed-air which can be interfaced with the customers electric power distribution system through a suitable Bi-directional power conversion process represent jly 211. The System Controller 217 contains at least one digital processing circuit that controls at a minimum the function of charge and discharge of the Energy Storage 214 through the Bi-direction Inverter 211 to the customer's electrical distribution system represented by 220.
In FIGURE 2 the preferred embodiment the System Controller 217 is a much more complex operating system containing multiple digital processors inter communicating with each other and the various elements of the Smart Energy Storage System. It is able to communicate through the External Communications Module 216 with various external devices such as but not limited to user power monitors, the electric utility and various other electrical consuming or generating devices connected to the customer's electrical distribution system. The External Communication Module 216 communicates with these external devices through port 215, which represents at least one external communication interface. This interface may be wireless bi-directional or wireless single directional communication and in combination with, or alternately through optical or electrical cables. The System Controller 217 controls the integration of the Renewable Power Converter 213 which is a common option used to interface electrical power generated by the customer connected through the external electrical connection 212, from but not limited to renewable sources such as solar, wind geothermal wave, tidal etc. to the customers electrical power system. For small installations such as those used by a home or residence the inclusion of this option greatly reduces the cost and time needed to install renewable energy sources such as wind or solar to the electrical grid. The installer only has to connect the external renewable power through input 212, add the Renewable Converter Module 213 to the Smart Energy Storage System and enable or install the upgraded software in the System Controller 217. For added convenience an electrical power meter 209 can be added to the Smart Energy Storage System in order to enable the recording of the amount of net renewable energy generated by the customer for their own use or sale to the electric utility with the net metered amount computed and made available to the utility either via communication or visual readout by the System Controller 217. The power meter 209 determines the net excess power generated by the Smart Energy Storage System by recording the net power that flows into and out of the Bi-direction Inverter 211 with any surplus power representing the power generated by the renewable power source connected at 212. The electrical power meter 209 can be relocated such that it is able to include the energy generated by an external electrical generator in additional to any other external power source as desired. The System Controller 217 operates a number of other elements such as but not limited to 207 an External Electric Generator used to either generate electric power continuously for use by the customer or in other embodiments it acts as an emergency electrical power source to replace the electric power from the utility that may have been interrupted., When the External Electric Generator 207 is first started its output power is disconnected from the Customer's Electrical System 220 by power relay 208, which may be mechanical or solid-state until the External Electric Generator's 207 output has reached suitable magnitude and phase to be connected to the customers electrical power distribution system 220.
When the External Electric Generator 207 is operating the Energy Storage 214 can be recharged and if the capacity of the Bi-Directional Inverter is adequate the External Electric Generator 207 can be operated at its most efficient point until the Energy Storage 214 is fully charged and then it can be shut off and the Customer's Electrical System 220 operated with stored electric power until the Energy Storage 214 is discharged to a preset minimum level at which point it can be restarted. The Power Relay 210 can be operated at any time by the System Controller 217 to disconnect the Bi-Directional Inverter 211 from the external electric generator. Operating the External Electric Generator 207 only when it is needed to recharge Energy Storage 214 saves both the operational life of the External Electrical Generator 207 but fuel as it can be operated at the point of its highest efficiency.
FIGURE 3 represents a major capability of the System Controller (FIGURE 2, 217) of the preferred embodiment of the disclosed invention. In FIGURE 3, 333 represents TO through T12 that are random time intervals when the customer's electric power usage changes.
Electric Utilities prefer customer loads that gradually increase or decrease because the electrical generating equipment can only increase or decrease the amount of available power on the electrical grid slowly.
To satisfy immediate electrical demand increases Electric Utilities must keep an amount of reserve generating power available to instantaneously provide the power from the surplus generating capacity consuming fuel without producing electrical power sales. The ideal system would be one where the Electric Utility is able to either immediately increase or decrease the amount of load on the electric grid in order to reduce the amount of surplus generating capacity it must keep on hot standby. Ideally the load control should be able to handle changes in the electrical demand instantaneously. The Smart Energy Storage System is designed specifically with that capability.
FIGURE 3 represents a number of different graphs of power consumption. Figure 3, 331 is the ideal customer from the Electric Utility's point of view, continuous unchanging load, easy to predict and provide power for. Figure 3, 332 is what the Electric Utility would see from a customer that generates part of its power from a renewable source and deliveries it through the electric grid and when they don't produce a surplus they draw electrical power from the electric grid. If the Electric Utility cannot have a customer that appears, as 331 then its next choice would be a customer that sells or uses power represented by the line 330. In line 330 the power supplied or used changes over a period of time not instantaneously allowing the Electric Utility to increase or decrease the amount of power it produces. Currently, all of the Electric Utility customer's deliver or use power like the curve represented by 332. This is not a major problem for Electric Utilities so long as it has a large number of customers and the changes in power consumption occur on a random basis. This is nearly true except that during the day there are times that the power demand peaks.
These time of the day events are consistent and currently Electric Utilities are able to predict the demand versus time of day with reasonable accuracy. However, this situation may be about to change with the use of net metering and smart home controllers that are designed to turn off loads during those times when electric power is expensive. The smart controllers will all respond to a common set of information turning on and off smart appliances in order to save customer's money. The problem is that consumers will no longer be an aggregate of random changes in electric power demand but will represent very large loads suddenly applied to the electric grid when the price for electric power is inexpensive and disconnected from the electric grid when the price is high.
This is the worse possible scenario for the Electric Utility, having a significant number of its customers synchronized so they in mass increase or decrease their demand. The preferred embodiment of the disclosed invention represented by FIGURE 2 is capable of providing to the Electric Utility a load such represented by 331 in FIGURE 3 or at worse a slowly changing load like 330. To achieve the customer load profile represented by 331 the System Controller 217 (all remaining references in this paragraph will be from FIGURES 2 or 3) will monitor the magnitude and phase of load current 201 in conjunction with the line voltage to calculate the power that the customer is drawing from the Electric Utility at 205. The System Controller 217 will then either delivery more power to the customer's local electric grid 220 or draw power from it by using the Bi-Direction Inverter in conjunction with the Energy Storage 214 in such magnitudes that the load to the Electric Utility appears to remain constant. The System Controller 217 has the additional capability to turn on or off the customer's smart electric loads through the External Communications Module 216 if the Bi-Directional Inverter 211 is not able to deliver or consume enough electrical power. If the size of the Energy Storage 214 or the capability of the B-Direction Inverter 211 is not adequate then the System Controller 217 can filter out the power increase or decreases over a time interval that matches the ability of the Electric Utility to increase or decrease the amount of electric power it generates. The System Controller 217 can also change the way that the electric power from the customers' renewable energy sources is delivered to the electric grid, by delivering it at another time of day.
The System Controller 217 monitors the customer's daily power usage and adjust the level of energy held by the Energy Storage 214 as needed to maintain its ability to supply energy from or to store energy to it.
It should be obvious to those that are experts in the state of the art of designing charging systems that electric vehicle chargers can represent a similar sudden increase or decrease in demand to the electric utilities. For example most workers either start work at a specific time or leave work at the same time. Plugging in or disconnecting electric vehicle chargers at those times would represent a simultaneous increase or decrease in electric power demand. Large parking lots will either need a Smart Energy Storage System to supplement the charging systems or use the gradual increase and decrease in electrical demand as a built in function of the chargers. Another solution is to use external communication with the utility to set the rate of charging, however even then it is preferred to use a preset rate of charger load increase when starting or decrease, when charging is completed to save the utility the complex task of processing potentially millions of smart electric devices in real time. At home the Smart Energy Storage System's Energy Storage 214 can be made large enough that it can provide the power to quickly recharge an electric car. It therefore follows logically that proposed fast recharge stations for electric cars will have to use large Smart Energy Storage Systems in order to be able to purchase electric power when it is inexpensive to recharge cars during the time of day when the demand for electric power is the highest.
These large fast recharge stations for electric cars would represent a very large amount of online Electric Grid Storage and could easily serve as a active electric Grid Storage systems used to help stabilize the Electric Utility's electric power network.
There are a number of other ways that the Smart Energy Storage System can be controlled, however most of them will require approval from and follow the guidelines set by the Electric Utility, with a few of the more common ones being:
i. The System Controller 217 FIGURE 2 monitors the Electric Utility's line voltage and during times when the line voltage is either abnormally low or in brownout the customer's load can be significantly decreased reducing the demand for electric power or delivering power to the electric grid.
ii. The System Controller 217 FIGURE 2 monitors the Electric Utility's line voltage and during times when the line voltage is either abnormally high or excessively peaking the customer's load can be significantly increased or the Energy Storage 214 charged increasing the demand for electric power helping to absorb the excess generating capacity.
iii. The Electric Utility directly controls, through the External Communications Module 216, the Smart Energy Storage System to change the amount of electric power the customer appears to be using or delivering power to the electric grid. In this way the Electric Utility has the ability to decrease demand during times when the amount electric power generation is inadequate or to increase demand by charging the Energy Storage 214 when there is a surplus of electric power available.
iv. Another method of control is by another company that directly controls, through the External Communications Module 216, the magnitude of the how much electric energy the Smart Energy Storage System either makes the customer appear to be using or even delivering to the electric grid. In this way the company can sell electric power into the electric grid when the price is high and recharge the Energy Storage 214 when the price for electric power is low.
The company would pay the customer for use of its Smart Energy Storage System.
v. Yet another method of control is that the System Controller 217 receives the time of use cost for electric power, through the External Communications Module 216, and then alters the magnitude of how much electric energy the Smart Energy Storage System makes the customer appear to be using. In this way the customer uses electric power from the Energy Storage 214 when the price is high and recharges the Energy Storage 214 when the price for electric power is low. The customer in this way reduces the magnitude of its electric power bill by using its Smart Energy Storage System.
vi. One other way the Smart Energy Storage System can be used is to store and provide electric power in those parts of the world that either don't have a reliable electric grid or none at all.
When there is no electric grid then an external power source such as electric generator or renewable energy source can be used to charge the Energy Storage 214. If there is an electric grid that is unreliable the customer can use the Smart Energy Storage System to store their own renewable energy and operate it as a UPS providing electric power when there is none available and storing surplus electric power for later use when it is available. Under these circumstances the System Controller 217 communicates with and controls the external power generating systems.
FIGURE 1 represents the process control used by the Smart Energy Storage System of the preferred embodiment when there is no external communications control, but connected to a reliable electric grid. FIGURE 1 represents the most basic of the functional control loops with a number of major changes possible depending on a number of external factors, described in detail in previous sections of the description of the preferred embodiment, that the Smart Energy Storage System is programmed to control. When the Smart Energy Storage System is turned on at START 100 it goes through a number of self check processes, not shown and then LOADS PRESETS 101 that the system must comply with. These presets may be defined by the utility, for the customer's safety or how the system is configured i.e. off the electric grid with an electric generator and solar electric power etc.. The Smart Energy Storage System then proceeds to 102 CHARGE TO
MINIMAL
LEVEL its Energy Storage 214, FIGURE 2 to the energy level that the system presets defines as minimally functional. Upon reaching that level the Smart Energy Storage System enters into its main function loop. It constantly monitors the electric grid voltage at LINE
VOLTAGE OK 103 &
107 and if line voltage is not adequate the Smart Energy Storage System will stop charging or discharging and the loop returns to the main entry point at LINE VOLTAGE
MONITOR 103. If the = line voltage at LINE VOLTAGE OK 103 is acceptable then it checks if it is the TIME OF DAY TO
CHARGE 104 if it is then proceed to 105 RECHARGE and if not then skip recharging and proceeds to TIME OF DAY TO DISCHARGE 106 and if its is the time for the user to run off of energy storage it then checks to see if the line voltage is acceptable at LINE
VOLTAGE OK 107. This check reflects one method the Utility uses to automatically over ride the time of day to run from storage operation. LINE VOLTAGE OK 107 generates NO condition if the line voltage is excessively high then returns to 103 aborting the decision to OPERATE FROM
STORAGE 108.
This is the indication from the Utility that there is a surplus of power in the grid. If the LINE
VOLTAGE OK 107 is nominal or low then the Smart Energy Storage System proceeds to 108 OPERATE FROM STORAGE. It then delivers the amount of electric power required by the customer from Energy Storage 214, FIGURE 2 in the manner it has been programmed to do so and while it is doing this it loops back to the start LINE VOLTAGE OK 103 to repeat the whole decision process.
= FIGURE 4 represents the process control used by the Smart Energy Storage System of the preferred embodiment when there is external communications control and connected to a reliable electric grid. FIGURE 4 represents the most basic of the externally controlled functional control loops with a number of major changes possible depending on a number of external factors, described in detail in previous sections of the description of the preferred embodiment, that the Smart Energy Storage System is programmed to control. When the Smart Energy Storage System is turned on at START 400 it goes through a number of self check processes, not shown and then LOADS PRESETS 401 that the system must comply with. These presets may be defined by the utility, for the customer's safety or how the system is configured i.e. off the electric grid with an electric generator and solar electric power etc.. Then the Smart Energy Storage System attempts to initiate at START EXTERNAL COM. 402 external communications. If it is successful it proceeds through SUCCESS to 403 LINE VOLTAGE OK. If instead it FAILED it loops through a preset , , time DELAY 409 then to TIMED OUT 410. If TIMED OUT 410 is NO it returns to START
EXTERNAL COM. 402 however if it is YES the Smart Energy Storage System will set the SYSTEM FAULT ALARM 411then return back to 402 START EXTERNAL COM where it continues to try to establish external communications. In many embodiments a limited form of the system operation will take place until proper communications are established.
If external communications is successfully established at START EXTERNAL COM. 402 then The Smart Energy Storage System often proceeds to CHARGE TO MINIMAL LEVEL, not shown, its Energy Storage 214, FIGURE 2 to the energy level that the system presets defines as minimally functional.
Upon reaching that level the Smart Energy Storage System enters into its main function loop. It constantly monitors the electric grid voltage at LINE VOLTAGE OK 403 & 407 and if line voltage is not adequate the Smart Energy Storage System will stop charging or discharging and the loop returns to the main entry point at LINE VOLTAGE MONITOR 403 in addition it continuously checks, not shown, that the external communications is active. If the line voltage at LINE
. VOLTAGE OK 403 is acceptable then it checks if it is the COMMAND TO
RECHARGE 404 has been given where if it is YES proceeds to RECHARGE 405 then 406 COMMAND TO
DISCHARGE and if NO it skips recharging and proceeds to COMMAND TO DISCHARGE
406.
At COMMAND TO DISCHARGE 406 the Smart Energy Storage System generates a NO if it isn't commanded to do so then returns to Line VOLTAGE OK 403. If COMMAND TO
DISCHARGE
406 is YES it proceeds to see if the line voltage is acceptable at LINE
VOLTAGE OK 407 where it is NO it returns to LINE VOLTAGE OK 403. If LINE VOLTAGE OK 407 is YES then the Smart Energy Storage System delivers the amount of electric power to the customer from Energy Storage 214, FIGURE 2 in the manner it has been externally commanded to do so at OPERATE FROM
STORAGE 408 and while it is doing this it loops back to the start LINE VOLTAGE
OK 403 to repeat the whole decision process.
To comply with the utility anti-islanding regulations during all modes of operation the Smart Energy Storage System closely monitors the utility's line voltage and frequency to determine if the utility has disconnected power from the customer at which point it will either switch to UPS
mode or shut down.
It is well known by one skilled in the art that many applications involving the change to the invention's operation based on the voltage of the external AC power source often involve the same change based on the change to the line frequency of said power source.
Although the invention has been described in connection with a preferred embodiment, it should be understood that various modifications, additions and alterations may be made to the invention by one skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (25)
PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. The Smart Energy Storage System with external data input from the external current transformer, with the data's magnitude and phase proportional to the sum of the current used by the customer added to that used by the Smart Electrical Energy Storage System, which is then used by the Smart Electrical Energy Storage System's System Controller in combination with the line voltage to calculate the electrical power consumed the value of which is then used by the System Controller to determine whether to change the state of charge of the electrical energy storage device, which when changed alters the apparent power the customer uses from the electric utility.
2. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the feature that allows customers to alter the system controller's programmed instructions.
3. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the ability to receive the signal through the communications interface, from the third party, that is decoded by the system controller to provide information to modify its operation.
4. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to alter the state of charge of the electrical energy storage device based on the state of the Electric Utility power source voltage and frequency.
5. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to alter the operating status of other electrical appliances to change the amount of power used from the Electric Utility based on the state of the Electric Utility power voltage and frequency.
6. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to change the phase relationship of the electric current drawn from the Electric Utility power source.
7. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to connect the electrical energy generated by an external source other than the primary Electric Utility power source for use by the Smart Energy Storage System.
8. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to turn on the electrical energy generated by the alternate external power source other than the primary Electric Utility power source for use by the Smart Energy Storage System and customer.
9. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to optimize the efficiency of delivery of externally generated electric energy also to it other than that provided by the primary Electric Utility power source.
10. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the amount of electric power generated by the external electric power source being measured and recorded with the recorded information made available by the system controller to be read from the communications interface.
11. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the magnitude and phase of the current used from the Electric Utility power source being measured by the external power meter which communicates the information to the system controller.
12. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to deliver power to the Electric Utility power source in addition to taking power from it.
13. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to provide power to the customer when power becomes unavailable from the Electric Utility power source.
14. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to operate the relay that disconnects the Smart Energy Storage System from the Electric Utility power source.
15. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the external disconnect switch that the utility uses to disconnect the Smart Energy Storage System from the Electric Utility power source.
16. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to operate the DC based customer power system rather than AC.
17. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to operate the mixed DC and AC power system rather than AC.
18. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller using the voltage, current magnitude and phase of the Electric Utility source to calculate and provide through the communications interface the amount of power consumed by the customer.
19. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller program that complies with anti-islanding requirement of the Electric Utility power provider.
20. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller is programmed to modify the apparent power used from the Electric Utility power source such that the rate of change in power usage is averaged over the period of time.
21. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller having at least one external communication interface from which it has the capability to receive information which is processed then used to modify the system controller's program.
22. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller providing at least one display with the interactive interface for the user of the system.
23. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the Renewable Power Converter that is used to charge the Energy Storage Device from a renewable power source.
24. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the Renewable Power Converter that provides power directly to the Smart Energy Storage System for use by the customer with surplus power made available for sale to the electric utility.
25. The Smart Energy Storage System with external data input from the external current transformer according to claim 1 including the system controller using the output of the current monitoring device to control the Smart Energy Storage System to provide all the electrical power required by the customer such that no electrical energy is exchanged with the Electric Utility power source.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2732592A CA2732592C (en) | 2011-02-21 | 2011-02-21 | Smart bi-directional electric energy storage and multifunction power conversion system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA2732592A CA2732592C (en) | 2011-02-21 | 2011-02-21 | Smart bi-directional electric energy storage and multifunction power conversion system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2732592A1 CA2732592A1 (en) | 2012-08-21 |
| CA2732592C true CA2732592C (en) | 2016-07-19 |
Family
ID=46717631
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2732592A Expired - Fee Related CA2732592C (en) | 2011-02-21 | 2011-02-21 | Smart bi-directional electric energy storage and multifunction power conversion system |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA2732592C (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115580523B (en) * | 2022-11-24 | 2023-03-10 | 石家庄科林电气股份有限公司 | Fault processing method and device for modular electric energy meter and electric energy meter |
-
2011
- 2011-02-21 CA CA2732592A patent/CA2732592C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CA2732592A1 (en) | 2012-08-21 |
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