Patent Application
20120123604
The embodiments described herein relate generally to electrical devices and, more particularly, to systems and methods for use in reducing a load on a power grid using devices that are operable on battery-power and on power obtained from the power grid.
At least some known electrical devices, such as computers, are operable using power received from the power grid or power stored in a battery. However, switching between power sources is generally a manual operation. For example, a user must physically disconnect the computer from the power grid in order to use energy stored in a battery. Moreover, at least some known electrical devices, such as home appliances, are not operable to use energy stored in a battery. To reduce the load on the power grid caused by such devices, generally the devices must be completely powered off. For example, a user may use a power switch at the appliance itself or may disconnect the appliance from the power grid using a circuit interruption device, such as a circuit breaker. However, such an action also requires the user to physically disconnect the appliance from the power grid.
In one aspect, a method is provided for controlling demand response of an electrical device that is configured to receive electrical power from at least one of a power grid and a battery. The method includes detecting a demand event at the electrical device while receiving power from the power grid, automatically disconnecting the electrical device from the power grid by a power management device and receiving power from the battery by the electrical device, and automatically reconnecting the electrical device to the power grid by the power management device.
In another aspect, a power management device is provided for use with an electrical device that is configured to receive electrical power from at least one of a power grid and a battery. The power management device includes a switch configured to selectively connect the electrical device to the power grid and the battery, and a processor coupled to the switch and configured to detect a demand event while the electrical device is connected to the power grid, cause the switch to disconnect the electrical device from the power grid and enable the electrical device to receive electrical power the battery, and cause the switch to reconnect the electrical device to the power grid.
In another aspect, a power management system includes at least one electrical device configured to receive electrical power from at least one of a power grid and a battery, and at least one power management device coupled to the electrical device. The power management device includes a switch configured to selectively connect the electrical device to the power grid and the battery, and a processor coupled to the switch and configured to detect a demand event while the electrical device is connected to the power grid, cause the switch to disconnect the electrical device from the power grid and enable the electrical device to receive electrical power from the battery, and cause the switch to reconnect the electrical device to the power grid.
Exemplary embodiments of systems, methods, and apparatus for enabling demand response in electrical devices are described herein. The embodiments described herein enable automated demand-responsive load management within a site, such as a house or business. Load management at such sites facilitates reducing a load on a power grid from an electrical device during peak times by switching the electrical device from using the power grid as an energy source to using a battery as an energy source.
In the exemplary embodiment, power grid 104 distributes power, such as electrical energy, to sites 106. Power grid 104 may include, but is not limited to only including, transformers (not shown) such as step-up and step-down transformers, and transmission and distribution lines (not shown) such as overhead power lines and underground power lines. However, power grid 104 may also include any other suitable equipment that facilitates transmission of power and/or communication signals to sites 106. Moreover, in the exemplary embodiment, power grid 104 distributes alternating current (AC) power using three-phase AC current or single-phase AC current. Alternatively, power grid 104 may distribute power direct current (DC), such as using high-voltage DC current.
In the exemplary embodiment, each site 106 includes at least one electrical device 110. As used herein, the term “electrical device” refers to any device that uses electrical energy to perform one or more functions, wherein the electrical energy is supplied by power grid 104 or is obtained from a battery. Exemplary electrical devices include computers, televisions, home appliances, or any other suitable device. The above examples are exemplary only, and thus are not intended to limit in any way the definition and/or meaning of the term “electrical device.” As shown in
Moreover, each site 106 includes at least one power management device 114 that is coupled to power grid 104 and to electrical device 110. As shown in
Moreover, in the exemplary embodiment, power management device 114 includes an AC/DC power converter 118 that converts AC power signals received from utility 102 via power grid 104 (shown in
In the exemplary embodiment, power management device 114 also includes a processor 124 that is coupled to network communication circuit 116, to power converter 118, and to switch 120. Processor 124 senses whether electrical device 110 is receiving DC power from power converter 118. Moreover, processor 124 processes demand event signals received by network communication circuit 116 and creates messages to transmit to computer 108 that acknowledge the demand event. Processor 124 also determines when electrical device 110 is to be removed from power grid 104 during times other than a demand event, such as when a current energy price is equal to, or greater than, a threshold price. Alternatively, processor 124 may detect when a change in an energy price over a specified time period is equal to, or greater than, a threshold amount. Accordingly, power management device 114 removes electrical device 110 from power grid 104 at times other than during a demand event, based on configurable variables. The configurable variables, such as the threshold price, the threshold change in price, and/or the time period over which the change in price is measured, may be configured by a user, a utility operator, and/or a manufacturer of electrical device 110 or equipment used by utility 102.
During normal operations, switch 120 is closed, thus enabling power converter 118 to transmit DC power signals to electrical device 110. Moreover, network communication circuit 116 senses incoming messages from computer 108 that are indicative of a demand event. When network communication circuit 116 receives a demand event message from computer 108, processor 124 causes network communication circuit 116 to respond with an acknowledgement message. Processor 124 also causes switch 120 to open, thus preventing power converter 118 from transmitting the DC power signals to electrical device 110. In response, electrical device 110 is no longer powered by power converter 118 but, rather, is powered by battery 112. During the demand event, network communication circuit 116 senses incoming messages from computer 108 indicative of an end of the demand event. When the demand event has ended, processor 124 causes switch 120 to close, thus enabling power converter 118 to transmit DC power signals to electrical device 110.
The demand event may be overridden by a user input or due to lack of charge in battery 112. For example, processor 124 and/or electrical device 110 monitor a charge status of battery 112. If the charge level becomes less than a threshold charge level, processor 124 causes switch 120 to close, thus enabling power converter 118 to transmit DC power signals to electrical device 110 and to recharge battery 112. When battery 112 is fully recharged or is charged beyond a desired level, processor 124 may cause switch 120 to open to remove electrical device 110 from power grid 104. Alternatively, a user may enter a user override command via electrical device 110 or power management device 114. In response to the user override command, processor 124 causes switch 120 to close, thus enabling power converter 118 to transmit DC power signals to electrical device 110. Processor 124 may also cause network communication circuit 116 to transmit a message to computer 108 that the demand event has been locally overridden.
In some embodiments, network communication circuit 116 also receives messages from computer 108 that are related to a current energy price. Processor 124 compares the current energy price to a threshold price. If the current energy price is higher than the threshold price, processor 124 causes switch 120 to open, to prevent power converter 118 from transmitting the DC power signals to electrical device 110. Similarly, processor 124 may determine a change in an energy price over a specified time period and compare the change to a threshold change. If the change in energy price is higher than the threshold, processor 124 causes switch 120 to open, thus preventing power converter 118 from transmitting the DC power signals to electrical device 110. In an alternative embodiment, processor 124 determines the current time and determines whether the current time is associated with a known period of high demand or load on power grid 104. If the current time is associated with such a known period, processor 124 causes switch 120 to open, thus preventing power converter 118 from transmitting the DC power signals to electrical device 110.
In response to the notification, power management device 114 causes electrical device 110 to switch 204 from power grid 104 as an energy source to battery 112 (shown in
Moreover, power management device 114 determines 212 whether a user override command has been entered. For example, processor 124 determines 212 whether a user override command has been entered and causes switch 120 to close in response to the user override command, thus enabling electrical device 110 to reconnect 214 to power grid 104. More specifically, processor 124 causes switch 120 to close, thus causing power converter 118 to transmit DC power signals to electrical device 110. Processor 124 may also cause network communication circuit 116 to transmit a message to computer 108 to notify computer 108 that the demand event has been locally overridden. If no override command has been entered, electrical device 110 will continue to receive power from battery 112. In the exemplary embodiment, power management device 114 or, more specifically, processor 124, receives 216 a notification indicative of the end of the power management event. In response to the notification, processor 124 enables electrical device 110 to receive power from power grid 104. For example, processor 124 causes switch 120 to close, thus enabling power converter 118 to transmit DC power signals to electrical device 110 and battery 112. In an alternative embodiment, the power management event may expire after a preselected time period. In such an embodiment, processor 124 detects that the time period has expired and causes switch 120 to close, thus enabling power converter 118 to transmit DC power signals to electrical device 110 and battery 112.
Exemplary embodiments of systems, methods, and apparatus for enabling demand response in electrical devices are described herein in detail. In the exemplary embodiment, a power management device receives a notification of a power management event from a utility through, for example, a home area network or a gateway. The power management device responds to the event by reducing the load on a power grid from one or more electrical devices by causing the electrical devices to switch to battery power. The electrical devices continue to use battery power until either the battery uses all or substantially all of its charge, or until the event is cancelled by the utility. If the battery uses a threshold amount of charge, the power management device enables the electrical device to resume receiving power from the utility while the battery recharges. When the battery has recharged fully or has charged to a specified level, the power management device either causes the electrical device to resume using battery power if the event is still in effect from the utility, or enables the electrical device to continue receiving power from the utility. The systems, methods, and apparatus are not limited to the specific embodiments described herein but, rather, operations of the methods and/or components of the systems and/or apparatus may be utilized independently and separately from other operations and/or components described herein. Further, the described operations and/or components may also be defined in, or used in combination with, other systems, methods, and/or apparatus, and are not limited to practice with only the systems, methods, and apparatus described herein.
Exemplary technical effects of the systems, methods, and apparatus described herein include at least one of: (a) receiving an electronic notification of a power management event; (b) automatically switching an electronic device from drawing power from a power grid to using power stored by a battery; (c) using a processor to monitor a charge level of the battery while the electronic device is disconnected from the power grid, automatically reconnecting to the power grid if the charge level is less than a preselected threshold, and recharging the battery; (d) detecting a user override command, automatically reconnecting to the power grid, and recharging the battery; and (e) receiving an electronic notification of an end of the power management event, reconnecting to the power grid, and recharging the battery.
A computer, such as those described herein, includes at least one processor or processing unit and a system memory. The computer typically has at least some form of computer readable media. By way of example and not limitation, computer readable media include computer storage media and communication media. Computer storage media include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules, or other data. Communication media typically embody computer readable instructions, data structures, program modules, or other data in a modulated data signal such as a carrier wave or other transport mechanism and include any information delivery media. Those skilled in the art are familiar with the modulated data signal, which has one or more of its characteristics set or changed in such a manner as to encode information in the signal. Combinations of any of the above are also included within the scope of computer readable media.
Although the present invention is described in connection with an exemplary power distribution system environment, embodiments of the invention are operational with numerous other general purpose or special purpose power distribution system environments or configurations. The power distribution system environment is not intended to suggest any limitation as to the scope of use or functionality of any aspect of the invention. Moreover, the power distribution system environment should not be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary operating environment.
Embodiments of the invention may be described in the general context of computer-executable instructions, such as program components or modules, executed by one or more computers or other devices. Aspects of the invention may be implemented with any number and organization of components or modules. For example, aspects of the invention are not limited to the specific computer-executable instructions or the specific components or modules illustrated in the figures and described herein. Alternative embodiments of the invention may include different computer-executable instructions or components having more or less functionality than illustrated and described herein.
The order of execution or performance of the operations in the embodiments of the invention illustrated and described herein is not essential, unless otherwise specified. That is, the operations may be performed in any order, unless otherwise specified, and embodiments of the invention may include additional or fewer operations than those disclosed herein. For example, it is contemplated that executing or performing a particular operation before, contemporaneously with, or after another operation is within the scope of aspects of the invention.
When introducing elements of aspects of the invention or embodiments thereof, the articles “a,” “an,” “the,” and “said” are intended to mean that there are one or more of the elements. The terms “comprising,” including,” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.
