Note: Descriptions are shown in the official language in which they were submitted.
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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
CA 02732592 2015-11-02
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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
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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.
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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
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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.
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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
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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
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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
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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
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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
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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
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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
,
CA 02732592 2015-11-02
, 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
CA 02732592 2015-11-02
16
invention by one skilled in the art without departing from the spirit and
scope of the invention as
defined in the appended claims.
