Note: Descriptions are shown in the official language in which they were submitted.
SPECIFICATION
System and Method for Intelligent Static Transfer Switch with Smart Home
Power Management
Field of Invention
[0001] The embodiments described herein relate generally to the
technical
field of supplying electric power to a home or office with different energy
sources.
More particularly, the embodiments relate to intelligent management and
transfer
switching that continuously supplies power in a seamless and efficient manner.
Background
[0002] Studies show that about 62% of power outages in North America
are weather related and 22% are caused by utility equipment failure. In
addition
to cost due to power and equipment failures, the price of producing
electricity
increases every year. Smart meters are now in place in order to monitor usage
at
any moment of time and pass the higher price of electricity during high demand
times to consumers. Therefore end users, e.g. residential homes and
businesses, are looking for solutions that could provide them with a reliable
(uninterrupted) electric power and at lower prices. Availability of the small-
scale
Distributed Energy Resources (DER) and Energy Storage Systems (ESS) for
home applications has introduced a new concept of Smart Home where the
consumers can easily be able to make intelligent energy choices of their
interest.
For example, the U.S. patent 4,644,320 and patent application 2003/0050737
disclose home energy control systems to minimize the cost of energy in a smart
home application.
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[0003] A common practice to supply power to a home in case of a
utility
failure is using a Backup Generator (BG). To transfer home loads to a BG, two
main technologies currently exist: 1- using a high capacity transfer switch at
the
main entrance; and 2- using several low capacity transfer switches that
connect
some essential loads to the BG. In the first approach, all the home loads are
supplied by a high capacity backup generator. The size of the BG, in this
approach, must be the same size of the total loads of the home. In the second
approach, only a small size generator is used to supply some essential loads
only, at the user's discretion. As an example, the United States patent
8,766,489
provides a solution based on using a transfer switch to connect backup
generators to supply power to home loads in case of a utility outage.
[0004] The existing transfer switches are mostly mechanical. They may
be
operated either manually or automatically. The minimum transfer time between
the utility and BG is typically about 1 minute. Therefore, there is always a
disruption. Also, none of the existing technologies can accommodate automatic
switching between different energy sources in a seamless manner.
[0005] The present invention provides a solution for the
abovementioned
shortcomings. Intelligent transfer switching can maintain continuous supply of
energy to a building from various sources of energy. In this approach, one or
more of backup generators, energy storage systems and distributed energy
resources (e.g. solar and wind) may be available to an end user, in addition
to
the main power utility. Furthermore, an intelligent power management system
may be utilized to balance supply of power between the main utility and other
energy sources in accordance with price of electricity in real-time in order
to
minimize consumption costs.
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SUMMARY
[0006] The
embodiments described herein provide in one aspect, a
system for automatic management of supply and distribution of electric power,
the system comprising: a main transfer switch unit connected to a plurality of
energy resources via a corresponding plurality of switches, and configured to
control input power received from the plurality of energy resources, and to
supply
power to a load management switches unit according to a first plurality of
control
signals; the load management switches unit, receiving power from the main
transfer switch unit, and configured to control supply of power to a plurality
of
loads according to a second plurality of control signals; and a monitoring and
power management unit communicating with the main transfer switch unit and
the load management switches unit, wherein the monitoring and power
management unit monitors load information and system information signals
received from the load management switches unit and from the main transfer
switch unit, and accordingly provides control signals for the main transfer
switch
unit and the second plurality of control signals for the load management
switches
unit in such a way that the electric power is seamlessly supplied to the main
transfer switch unit and the plurality of loads; wherein the main transfer
switch
unit is configured to couple to a power utility and to at least one energy
resource
selected from a backup generator, a battery, and an alternative energy source,
with an EXOR logic mode and with an OR logic mode; wherein, in EXOR logic
mode, the main transfer switch unit is configured to transfer power from the
power utility to the at least one energy resource when there is a power outage
in
the power utility; and wherein, in OR logic mode, the main transfer switch
unit is
configured to transfer power to the plurality of loads from both the power
utility
and the at least one energy resource for reducing a cost of power consumption
from the power utility.
[0007] The
embodiments described herein provide in another aspect a
method for automatic management of supply and distribution of electric power,
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the method comprising: monitoring load information and system information
signals received from a load management switches unit and from a main transfer
switch unit, the main transfer switch unit being connected to a plurality of
energy
resources via a corresponding plurality of switches, the load management
switches unit receiving power from the main transfer switch unit; and
providing
control signals for the main transfer switch unit and for the load management
switches unit according to the load and system information, wherein the load
management switches unit is configured to control supply of power to a
plurality
of loads according to a second plurality of control signals, and wherein the
main
transfer switch unit is configured to control input power received from the
plurality
of energy resources and to supply power to the load management switches unit
according to a first plurality of control signals; wherein a monitoring and
power
management unit monitors load information and system information signals
received from the load management switches unit and from the main transfer
switch unit, and accordingly provides control signals for the main transfer
switch
unit and the second plurality of control signals for the load management
switches
unit in such a way that electric power is seamlessly supplied to the main
transfer
switch unit and the plurality of loads; wherein the main transfer switch unit
is
configured to couple to a power utility and to at least one energy resource
selected from a backup generator, a battery, and an alternative energy source,
with an EXOR logic mode and with an OR logic mode; wherein, in EXOR logic
mode, the main transfer switch unit is configured to transfer power from the
power utility to the at least one energy resource when there is a power outage
in
the power utility; and wherein, in OR logic mode, the main transfer switch
unit is
.. configured to transfer power to the plurality of loads from both the power
utility
and the at least one energy resource for reducing a cost of power consumption
from the power utility.
[0008] The embodiments described herein provide in another aspect a
programmable power management apparatus comprising a microprocessor, the
apparatus configured to: monitor load information and system information
signals
received from a load management switches unit and from a main transfer switch
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unit the main transfer switch unit being connected to a plurality of energy
resources via a corresponding plurality of switches, the load management
switches unit receiving power from the main transfer switch unit; and provide
control signals for the main transfer switch unit and for the load management
switches unit according to the load and system information, wherein the load
management switches unit is configured to control supply of power to a
plurality
of loads according to a second plurality of control signals, and wherein the
main
transfer switch unit is configured to control input power from the plurality
of
energy resources and to supply power to the load management switches unit
in according to a first plurality of control signals; wherein a monitoring
and power
management unit is configured to monitor load information and system
information signals received from the load management switches unit and from
the main transfer switch unit, and accordingly provide control signals for the
main
transfer switch unit and the second plurality of control signals for the load
management switches unit in such a way that electric power is seamlessly
supplied to the main transfer switch unit and the plurality of loads; wherein
the
main transfer switch unit is configured to couple to a power utility and to at
least
one energy resource selected from a backup generator, a battery, and an
alternative energy source, with an EXOR logic mode and with an OR logic mode;
wherein, in EXOR logic mode, the main transfer switch unit is configured to
transfer power from the power utility to the at least one energy resource when
there is a power outage in the power utility; and wherein, in OR logic mode,
the
main transfer switch unit is configured to transfer power to the plurality of
loads
from both the power utility and the at least one energy resource for reducing
a
cost of power consumption from the power utility.
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Brief Description Of The Drawings
[0009] For a better understanding of the embodiments and/or related
implementations described herein and to show more clearly how they may be
carried into effect, reference will now be made, by way of example only, to
the
accompanying drawings which show at least one exemplary embodiment and/or
related implementation in which:
[0010] Figure 1 illustrates a top level diagram of an embodied power
supply and distribution system;
lo [0011] Figure 2 illustrates an exemplary main transfer switch unit,
as
embodied in the invention;
[0012] Figure 3 illustrates an exemplary load management switches
unit
as embodied in the invention; and
[0013] Figure 4 illustrates an exemplary intelligent monitoring and
power
management system, as embodied in the invention.
[0014] It will be appreciated that for simplicity and clarity of
illustration,
elements shown in the figures have not necessarily been drawn to scale. For
example, the dimensions of some of the elements may be exaggerated relative
to other elements for clarity. Further, where considered appropriate,
reference
numerals may be repeated among the figures to indicate corresponding or
analogous elements.
Detailed Description of the Embodiments
[0015] Embodiments of the present invention will now be described
fully
hereinafter with reference to the accompanying drawings, in which the
embodiments of the invention are shown by way of illustration and example.
This
invention may, however, be embodied in many forms and should not be
considered as limited to the embodiments set forth herein. Rather, these
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embodiments are provided so that this disclosure will be thorough and
complete,
and will fully convey the scope of the invention to those skilled in the art.
Like
numerals refer to like elements.
[0016] It will be
appreciated that numerous specific details are set forth in
order to provide a thorough understanding of the exemplary embodiments
described herein.
[0017] However, it will be
understood by those of ordinary skill in the art
that the embodiments and/or implementations described herein may be practiced
without these specific details. In other instances, well-known methods,
procedures and components have not been described in detail so as not to
obscure the embodiments and/or implementations described herein.
Furthermore, this description is not to be considered as limiting the scope of
the
embodiments described herein, but rather to describe the structure and
operation
of the various embodiments and/or implementations described herein.
[0018] FIG.1 illustrates a
top level diagram of an embodied power
distribution management system. Accordingly, the system comprises a Main
Transfer Switch unit 200; a Load Management Switches unit 300; and an
Intelligent Monitoring and Power Management unit 400. In one embodiment, the
switches in the system may be static AC switches (e.g. using SCR) that can get
turned on/off by a command signal, where the transfer time between different
sources is about 1/4 cycle (4msec). That meets the IEEE power quality
standards (IEEE Standard for Interconnecting Distributed Resources with
Electric
Power Systems," in IEEE Std 1547-2003, vol., no., pp.1-28, July 28 2003; and
IEEE Recommended Practice for Monitoring Electric Power Quality," in IEEE Std
1159-2009 (Revision of IEEE Std 1159-1995), vol., no., pp.c1-81, June 262009)
and comply with the CBEMA curve, as known in the art (e.g. see Kusko, A. and
Thompson, M. (2007). Power Quality in Electrical Systems. New York: McGraw-
Hill).
[0019] The main transfer
switch 200 may be located between the main
entrance switch (main breaker) and the main circuit breakers panel commonly
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installed in residential or commercial building units. As shown in FIG. 1, the
main
transfer switch 200 receives input power from a plurality of Energy Resources
100. The main transfer switch 200 may be configured to provide supply of power
to the load management switches 300. The load management switches 300
controls operation of a plurality of non-priority (also referred to as low
priority)
loads 320. Optionally, the main transfer switch 200 may be configured to
provide
supply of power for a plurality of priority loads 340 in the unit directly.
The priority
loads 340 are meant to be powered at all times, such as emergency signs and
elevators in a building.
[0020] The energy resources 100 include the main electrical utility 120
supplied to the building. Additionally, the energy resources 100 may include
at
least one Backup Generator 140, at least one Battery Energy Storage 160, and
one or more alternative sources of energy 180 such as a Photovoltaic (PV)
and/or Wind Energy. It should be noted that the alternative energy resources
180
are not limited to PV and wind components that are shown in FIG.1. The
disclosed teachings are applicable to any existing or future source of energy
that
may be convertible to electric power, as will be appreciated by practitioners
of the
art.
[0021] It should also be noted that the flow of power between the
main
transfer switch 200 and the battery energy storage 160 is bi-directional, as
shown
in FIG.1. That is, the main transfer switch 200 may be employed to charge the
battery energy storage 160, normally through a battery charger, when required.
In this configuration, the input power may be provided by the power utility
120,
when the utility is available. Alternatively, the input power may be provided
by the
backup generator 140 and/or the alternative sources 180, when the utility is
unavailable. In one example, the system may be programmed to charge the
battery with the utility 140 power during off-peak times and using cheaper
electricity. In another example, the system may be programmed to charge the
battery with the power from the backup generator 140 during a power outage,
and when non-priority loads are not in use.
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[0022] The load management switches 300 may be located after the main
circuit breakers. The load management switches 300 may connect/disconnect
low priority loads 320, for example, during the operation of the backup
generator
140 or the battery 160. In one embodiment, the load management switches 300
comprise static AC switches.
[0023] The intelligent monitoring and power management unit 400
continuously monitors, via wired or wireless connections, the load
currents/voltages in the main transfer switch 200 and the load management
switches 300 to ensure that the power is efficiently provided to the priority
loads
340 all the time and to the non-priority loads 320 when required.
[0024] FIG. 2 is an exemplary schematic of the main transfer switch
200 in
relation with the other components of the system. It comprises n number of
switches, preferably static AC switches, where n is the number of all the
available
sources of power to a building unit, including the main utility 120. Two modes
of
operations may be implemented for the main transfer switch 200, as illustrated
in
FIG. 2: 1- the loads may be connected to the utility 120 and to other (non-
utility)
energy sources of 100 with EXOR logic; and 2- the loads may be connected to
the utility 120 and to other (non-utility) energy sources of 100 with OR
logic.
[0025] In one embodiment, the EXOR mode of operation may be adapted,
zo where the main transfer switch 200 facilitates the power transfer from
the utility
120 to other sources 140-180 in a fully automated manner. An example of this
mode of operation is a power outage when the utility 120 would be unavailable.
[0026] In another embodiment, the OR logic operation may be adapted,
where the loads may be connected either to the utility 120 or to the other
sources
140-180, or to both the utility 120 and the other sources 140-180 at the same
time. For example, this mode of operation may be adapted to reduce the cost of
power consumption during peak hours by reducing supply from the utility 120
and
extracting the needed power from the other sources 140-180 instead.
[0027] An exemplary architecture of the load management switches unit
300 is illustrated in FIG. 3. The load management switches unit 300 may be
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located after the main circuit breakers. Its primary function is to
connect/disconnect low priority loads 32041) to 320-(n). For example, during
the
operation of the backup generator 140 some or all these loads may be
disconnected in order to keep the priority loads 340 powered for a longer
period
of time. The load management switches unit 300 receives proper control
signals,
e.g. on/off signals 350, from the intelligent monitoring and power management
unit 400.
[0028] FIG. 4 illustrates one embodiment of the invention, where the
intelligent monitoring and power management unit 400 is shown in constant
io communication with other components of the system. The monitoring and
power
management unit 400, being the brain of the system, may comprise a
microprocessor. It keeps monitoring the load currents/voltages and provides
power for the priority loads 340 all the time. The voltage and current signals
of all
energy sources are measured and sent to the intelligent power management unit
400 for the sake of monitoring and power management. Other information such
as outside temperature, temperature of components of the system, date, time,
etc may also be gathered by the intelligent monitoring and power management
unit 400. Based on the information from the system conditions, intelligent
logics
determine the proper control signals for the main transfer switch unit 200 and
load management switches unit 300. The proper control signals may be, but are
not limited to, on/off signals 350. Varying voltages/currents, phase control
and
pulse control are other examples of control signals.
[0029] In one embodiment, the intelligent monitoring and power
management unit 400 sends and receives all the system information to a main
server 600 wirelessly, for the sake of system maintenance and continuous
monitoring and event logging, in addition to wirelessly communicating with the
main transfer switch 200 and the load management switches 300. Accordingly,
all system components may be equipped with wireless communication means.
This capability may in turn be utilized in remote control and operation of the
system, for example via the Internet, smart phone applications, etc. The main
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server 600 may be locally suited in the building or may be located externally,
for
instance with a service provider.
[0030] The monitoring and power management unit 400 may be
programmed by a user or a technician for a fully automated control and
management of power by the unit 400. In one embodiment, instructions may be
uploaded to the unit 400 via a Graphic User Interface (GUI) application on a
personal computer. In another embodiment, instructions may be uploaded to the
unit 400 remotely by a service provider.
[0031] The intelligent monitoring and control provides end users with
flexible methods of power management. According to an exemplary embodiment,
if the consumption of the priority loads 340 and non-priority loads 320
exceeds
the capacity of the back-up resources during a power outage, the intelligent
power management unit 400 may decide to shift powering of all or a portion of
the non-priority loads 320 to another time.
[0032] According to another exemplary embodiment, the consumption of
energy during peak hours or peak usage may be redistributed among one or
more of non-utility energy sources in addition to the utility 120. For
example, the
intelligent monitoring and power management unit 400 may shift a portion of
the
input energy supplied by the main utility 120 to one or more of the backup
zo generator 140, battery energy storage 160 or the alternative sources
180. Such a
multi-switching redistribution method would directly result in a considerable
price
reduction and savings. In fact, it may be performed in real-time in accordance
with a time-of-use pricing instruction. Other factors, such as time of day,
may
come into consideration too. For instance, using a quiet battery would be more
proper than using a noisy backup generator during late night or early morning
hours.
[0033] In one embodiment, the system includes a Display unit 500. All
major information, the system condition, and operation of each energy source
may be shown on the display unit 500. The display unit 500 may be a touch
screen type with a multi-page capability for user interactions. Changing the
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settings and the modes of operations can also be achieved through the control
page of the display unit 500.
[0034] While the above description provides examples of the
embodiments, it will be appreciated that some features and/or functions of the
described embodiments are susceptible to modification without departing from
the spirit and principles of operation of the described embodiments.
Accordingly,
what has been described above has been intended to be illustrative of the
invention and non-limiting and it will be understood by persons skilled in the
art
that other variants and modifications may be made without departing from the
scope of the invention as defined in the claims appended hereto.
[0035] Although the invention has been described relative to various
selected embodiments herein presented by way of example, there are numerous
variations and modification that will be readily apparent to those skilled in
the art
in light of the above teachings. It is therefore to be understood that, within
the
scope of the claims hereto attached and supported by this specification, the
invention may be practiced other that as specifically described.
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