WO2008077654A1

WO2008077654A1 - Electrical power usage controller

Info

Publication number: WO2008077654A1
Application number: PCT/EP2007/059569
Authority: WO
Inventors: Luigi Pichetti; Marco Secchi; Antonio Secomandi; Alessandro Donatelli
Original assignee: International Business Machines Corporation; Compagnie Ibm France
Priority date: 2006-12-27
Filing date: 2007-09-12
Publication date: 2008-07-03
Also published as: WO2008077654A9; EP2098013A1; JP2010515411A; CN101573918A; KR20090102750A

Abstract

A solution is proposed for an integrated system which tries to prevent and manage power break down in home electrical system with an interaction between the appliances or the electricity points within the house and a server controlling the system. A server (105) is connected to the meter (201) and to a plurality of agents (110). In a state of the art home electrical system the device (105) provides a new functionality which can range from a mere alerting service to a proper control and management of the electricity consumption within the house. Server (105) could be located anywhere between the main meter/switch, normally provided by the electrical distribution company, and the household appliances or, more in general, the electrical devices to be managed. Its preferred location is however inside the apartment itself, near the remainder of the main internal switches. Connected to the Server (105) there are several clients which are associated to one or more switches or plugs.

Description

ELECTRICAL POWER USAGE CONTROLLER

Field of the Invention

The present invention relates to the information technology field. More specifically, the invention relates to electrical power metering systems.

Background Art

It is well known in the field of Electric Utility Companies to use methods and systems for metering electrical energy in its various possible forms by means of electrical meters. Commercially available electrical meters normally belong to one of two main categories: the electromechanical meters which normally use a rotating disk to generate the metering and have a magnetic-thermic switch for avoiding overloads; the second category includes electronic digital meters which are based on electronic components and do not need any mechanical rotating parts and have an embedded switch.

A common problem to both kind of meters is that when a power theresholds is reached a security mechanism of the meter is invoked which operates the corresponding switch which cut the electric supply to the whole system connected to that meter . Known solution to this problem, is to buy one or more uninterruptible power supply (UPS) system and connect "key" appliances (a PC, TV set, DVD recorder, cordless phone, clocks, etc) to such devices. This however is of limited use, as commercial UPS systems for home-usage are able to support a quite limited amount of electrical power supply (100 to 500W). Such limitation prevents using them both for power consuming appliances, but also plenty of small appliances, which are usually located in different location of the house. Moreover, solutions based on back-up systems, would not solve the fact that the main electrical switch (the one owned by the supplier company, associated to the kWh meter) will turn off, and the user would be obliged to physically move there (usually in the basement of the building, or in an outside cabinet on the road) to turn it on.

For greater business (offices, hospitals, etc) the usage of powerful alternators (5, 50, 500 kW) with their own fuel-powered engine, can address the situation, but this solution is not suitable for single apartments. Also known in the art and commercially avaible, are systems which alert the user when the thresholds is reached or it is likely to be reached soon.

In any case what is lacking is an integrated system which tries to prevent and manage these accidents with an interaction between the appliances or the electricity points within the house and the electric meter.

It is an object of the present invention to overcome the above described drawbacks of the prior art.

Summary of the Invention

According to the present invention we provide a method for controlling electrical power usage in a system including an electricity meter, the meter being connected to a server element, the server element monitoring the total electrical power usage of the system and communicating with a plurality of client elements, each client element controlling at least one electrical power consuming element, the method including the steps of: each client monitoring the at least one electrical power consuming element; responsive to a start command for the at least one electrical power consuming element the server receiving a request of electrical power by the associated client; the server evaluating the amount of electrical power needed to satisfy the request; if the request can be satisfied without exceeding a predefined maximum allowed load of the system, granting the requested electrical power; if the request cannot be satisfied without exceeding the maximum allowed load of the system, suspending the request and invoking a recovery action. A further aspect of the invention proposes a computer program for performing the above-described method.

A still further aspect of the invention proposes a service for performing the same method.

Another aspect of the invention proposes a corresponding system.

In this way the various domestic loads, through the associated client, interacts with a central server which can control the overall load and avoid that a predetermined power thresholds is trespassed.

Reference to the drawings

The invention itself, as well as further features and the advantages thereof, will be best understood with reference to the following detailed description, given purely by way of a non-restrictive indication, to be read in conjunction with the accompanying drawings, in which:

Figure 1 is a schematic block diagram of a data processing system in which the solution according to an embodiment of the invention is applicable; Figure 2 illustrates an exemplary application of the solution according to an embodiment of the invention;

Figure 3a-3b show examples of a representation of the control and power flows which occur during the interactions between the server and the client units according to two embodiments of the invention; and

Figure 4 is a diagram describing the flow of activities relating to an implementation of the solution according to an embodiment of the invention.

Detailed Description

With reference in particular to Figure 1, a distributed data processing system 100 is illustrated. The system 100 has a client/server architecture, wherein servers 105 (only one shown in the figure) manage a plurality of clients 110. Multiple clients 110 are connected to server 105 (for example, clients 110 can be coupled to household or electronics appliances, e.g. washing machine, DVD recorders, computers) . For this purpose, the server 105 and the clients 110 communicate through a network which allows to communicate the intention to turn on the appliance/switch associated to a given client; typically, the network 115 is implemented by means of a medium which is able to carry electronic control signals, for example by means of conveyed waves, which is a common method to propagate low voltage control signals over regular electrical wires (e.g. 220/110 volts and 50/60 hertz). This allows each client 110 to access the server 105, even remotely. Besides conveyed waves over electrical wires, alternative ways can be used for exchanging control signals between server and clients, e.g. any radio frequency signals, suitable for home-ranges (i.e. WiFi) or Bluetooth signals.

Particularly, the server 105 consists of a computer being formed by several units that are connected in parallel to a system bus 120. In detail, one or more microprocessors (//P) 125 control operation of the server 105; a RAM 130 is directly used as a working memory by the microprocessors 125, and a ROM 135 stores basic code for a bootstrap of the server 105. Several peripheral units are clustered around a local bus 140 (by means of respective interfaces) . Particularly, a mass memory consists of one or more hard-disks 145. Moreover, the server 105 includes input units 160 (for example, a keyboard), and output units 165 (for example, a monitor) . An adapter 170 is used to connect the server 105 to the network 115. A bridge unit 175 interfaces the system bus 120 with the local bus 140. Each microprocessor 125 and the bridge unit 175 can operate as master agents requesting an access to the system bus 120 for transmitting information. An arbiter 180 manages the granting of the access with mutual exclusion to the system bus 120.

With reference now to Figure 2, server 105 is connected to the meter 201 and to a plurality of agents 110. In a state of the art home electrical system this device 105 provides a new functionality which can range from a mere alerting service to a proper control and management of the electricity consumption within the house. For the rest of the present description we will refer to the server 105 as "power enabler device" (PED) . PED could be located anywhere between the main meter/switch, normally provided by the electrical distribution company, and the household appliances or, more in general, the electrical devices to be managed. Its preferred location is however inside the apartment itself, near the remainder of the main internal switches (normally used to section the electrical network between e.g. 10 and 16 A loads) . Connected to the PED 105 there are several clients which are associated to one or more switch or plug. The amount of logic of these clients may vary to a great extent and the services provided by such clients are strictly dependent on such logic.

In any case, according to a preferred embodiment of the present invention, the role of the PED is to give consensus, whenever a new appliance is being turned on. We foresee different ways of working of the PED, depending on the amount of logic that we can assume to be inside the different internal switches of the house:

(A) Switch which is only able to communicate its ID; (B) Switch which is able to communicate its ID and receive a consensus signal;

(C) Switch which is also able to remember last required load.

A. Static loads method for every internal switch and appliance (wall socket) , whereas each switch is only able to send its ID

In this scenario, generally represented with 300 in Fig. 3a, each internal switch located in the house (for either turning on lights or enabling a wall socket) , is able to transmit over the wire a unique signal ID (e.g. unique deviation out of a base CW frequency, or a unique resistance) each time it's turned on (or pressed) .

PED receives all these signal IDs from switches being turned on, and have a static table where, for each switch ID, it lists the associated known load. As PED also includes a power meter, so it's instantly aware of the current total load in use, it's able to forecast if, giving power to the wire from which the specific switch is connected, the total power threshold would be violated, and in this case it won't activate the specific wiring, that connects PED to the specific switch. In this scenario, every switch (for which a sensible load is known to be possibly connected) must have a direct wiring which connects it to the PED; such wire is usually not powered (it only allows ID signal exchange) and gets powered with 220/110 voltage, only if consensus is given from PED.

In case of switches which are powered from intermediate junctions, and that have no direct wiring with the master-PED, slave PEDs could be added in the intermediate junctions. In this scenario, PED must know how much electrical power a switch will absorb, and this information can be statically defined in PED configuration, although it could optionally be self updated as consensus is given (usage statistics) , with an optional time-based reset policy.

Wall outlets, could be thought with a similar RF identification, although, as different appliance may be connected to the same outlet, the configuration should be done a priori. A limitation of this scenario is the static load pre-configuration, and the need to direct PED-switch wires, or of intermediate PEDs. The advantage is the limited logic needed in the switch.

With reference to Fig 3a, activity 1 indicates the request from the end-user of an electrical load activation e.g. by pressing the Sender-Switch. In activity 2 the Sender/Switch sends a control command to the central PED server, through which it communicates its unique ID. Activity 3 represents the check by the PED of the last known power consumption from the load above. Then (activity 4) PED compares the required power from the load with the available one (AvailableLoad = MaximumAllowed - CurrentUsage SpareBuffer) and eventually gives power to the wire which connects PED to Sender-Switch and its controlled load. Finally (activities 5 and 6) wire is activated from PED and power flows to Switch and load.

B. Static loads method for every internal switch and appliance (wall socket) , whereas each switch is able to send its ID and receive a consensus signal .

In this scenario B (represented in Fig. 3b with 305) each switch is not only able to send an ID signal to the PED, but is also able to receive a consensus signal, over the wire.

Once such consensus signal is received (e.g. a CW signal) , it will then activate the power to the associated appliance, acting in a "relais" mode. The advantage of this solution, is that no direct wiring is needed from PED to switches, as consensus signals are routed through junctions to the proper switch (e.g. "<switchID><ack>" or "<switchID><noack>") .

Also, in this case all junction wires to the switches are always powered (as in today's layouts) and it's the switch that, working in relais-mode, powers the appliance when consensus is got from PED. Switches really act as real power switches, as they do today, with the difference that power-on happens only if they receive consensus from the PED.

With reference to Fig 3b, activity 1 represents End user request of an electrical load activation pressing the Sender-Switch. Then (activity 2) Sender-Switch sends a control command to the central PED server, through which it communicates its unique ID. Switch remains listening for ack/nack. PED lookups (activity 3) last known power consumption from the above load, then (activity 4) it compares the required power from the load with the available one (AvailableLoad = MaximumAllowed - CurrentUsage - SpareBuffer) and eventually sends a consensus (ack) signal to the Switch. Finally (Activity 5) Switch receives consensus control signal from PED, and in turn the Switch, working in relais mode, activates power connection to the load (activity 6) .

C. Internal switches and PED implementing a dynamic behavior

In this third example scenario each internal switch, in addition to be able to send its ID (sender) and to receive a consensus signal from PED (CW receiver) , is also able to remember the last required load from the served appliance. In this case the amount of power required from each switch/load may not be known a priori from PED, but switches are able to remember last used load. PED in this case, must only reply to the given switch ID which made the request, that the requested amount of load is available, as it won't exceed the total available load.

So for instance, <ID> and <needed power>, are communicated from the switch to the PED, and there is no more need of a lookup on a static table (activity 3 of Figures 3a and 3b) . Also it's possible to have some manual control on the switch itself (500W, IkW, 2kW, etc) in case it's serving nomadic appliances, through a controlled wall outlet.

It's not essential though that this "load-memory" functionality is available inside each switch, and could be also located in the PED itself (keeping track of last power usage associated to each switch ID, with the optional ability for a time-based auto reset, or a manual reset) .If consensus is not given, an alert (beep) is fired from the requesting switch.

Passing now to Figure 4, the logic flow of an exemplary process that can be implemented in the above-described system to manage the power load (or overload) within a plurality of house appliances is represented with a method 400. The method begins at start block 401 and passes to block 403 where the total system power usage is monitored by the PED. A communication from a switch, controlling its electrical load is received by the PED 105 from one of the clients 110 (step 405) . The expected new requested load is estimated by the system (step 407), e.g. by means of a look-up table by the PED or directly communicated by the client 110. If the addition of the expected new requested load to the current one does not exceed the predetermined maximum allowed power of the meter/switch 201 (step 409) then authorisation is given to the client 110 and supply of power is granted (step 411) , otherwise alternative recovery solution is implemented (step 413); in this case the request is suspended but the rest of the system does not suffer of any breakdown as with prior art systems. The range of possible recovery solutions is very broad and could be a simple communication to the client (and finally to the user) that the new request is not receivable (e.g. by means of an alarm) or a more complex management of the power load depending on the logic contained in the clients 110. The control messages exchanged between the PED Server and the plurality of clients 110 can be of several different types, depending on the level of complexity of each client. If the client 110 is only able to send its unique identity, then the PED will need to directly control the electrical power which has to be granted to the client switch, as the client is not able to receive a consensus signal; this has implications in the electrical wiring, as star-wiring form PED to client would be need (as described for scenario A above) . On the other hand, if the client is also able to receive a consensus control signal (e.g. a CW receiver is implemented) , then the set of messages exchanged from PED and clients could be more complex and PED could avoid a direct control of the electrical power supply to clients, thus delegating the clients for the activation of the electrical load, once the consensus signal is issued by the PED (see scenario B above) . In a further extension, client 110 may also be able to communicate additional attributes of the controlling load, so that it could be able e.g. to report the expected load demand, according to current load settings or last/historical power demand for the controlling load; this information allows PED to operate in a more dynamic way, without the need of manual power-usage settings for the different controlling client loads (see above described scenario C) . Furthermore more complex recovery actions could be implemented, e.g. one of the currently connected appliances or devices could be disconnected to allow the new request to be satisfied, according to a predefined priority list.

Naturally, in order to satisfy local and specific requirements, a person skilled in the art may apply to the solution described above many modifications and alterations. E.g. monitoring step 403 could be done only when needed, i.e. when the request at step 405 is received by the PED. Particularly, although the present invention has been described with a certain degree of particularity with reference to preferred embodiment (s) thereof, it should be understood that various omissions, substitutions and changes in the form and details as well as other embodiments are possible; moreover, it is expressly intended that specific elements and/or method steps described in connection with any disclosed embodiment of the invention may be incorporated in any other embodiment as a general matter of design choice.

Particularly, similar considerations apply if the system has a different structure or includes equivalent servers and/or clients. In any case, the proposed solution lends itself to be applied to scenarios in which clients 110 are able to report additional information to the controlling PED which could be taken into account when taking the decision; this may include load priority, for possible pre-emption of different active loads, introspection of load setting etc. It may also be possible to extend the solution to different environments, e.g. to implement a control of a whole building or using different communication means among clients and PED. Similar considerations apply if the program (which may be used to implement each embodiment of the invention) is structured in a different way, or if additional modules or functions are provided; likewise, the memory structures may be of other types, or may be replaced with equivalent entities (not necessarily consisting of physical storage media) . Moreover, the proposed solution lends itself to be implemented with an equivalent method (by using similar steps, removing some steps being not essential, or adding further optional steps - even in a different order) . In any case, the program may take any form suitable to be used by or in connection with any data processing device, such as external or resident software, firmware, or microcode (either in object code or in source code) . Moreover, it is possible to provide the program on any computer-usable medium; the medium can be any element suitable to contain, store, communicate, propagate, or transfer the program. For example, the medium may be of the electronic, magnetic, optical, electromagnetic, infrared, or semiconductor type; examples of such medium are fixed disks (where the program can be pre-loaded) , removable disks, tapes, cards, wires, fibers, wireless connections, networks, broadcast waves, and the like.

In any case, the solution according to the present invention lends itself to be implemented with a hardware structure (for example, integrated in a chip of semiconductor material), or with a combination of software and hardware. Even though in the preceding description reference has been made to a physical implementation of the proposed solution on the server, this is not to be intended as a limitation. Indeed, in a different embodiment of the invention the same solution may be deployed by means of a service, which is offered by a corresponding provider.

Alternatively, the proposed method may be implemented on a computer with a different architecture or that includes equivalent units (such as cache memories temporarily storing the programs or parts thereof to reduce the accesses to the mass memory during execution) ; more generally, it is possible to replace the computer with any code execution entity (such as a PDA, a mobile phone, and the like) .

Claims

1. A method for controlling electrical power usage in a system connectable to an electricity meter, the system including a server element, the server element monitoring the total electrical power usage of the system and communicating with a plurality of client elements, each client element controlling at least one electrical power consuming element, the method including the steps of: each client monitoring the at least one electrical power consuming element; responsive to a start command for the at least one electrical power consuming element the server receiving a request for electrical power by the associated client; the server evaluating the amount of electrical power needed to satisfy the request; if the request can be satisfied without exceeding a predefined maximum allowed load of the system, the server granting the requested electrical power; if the request cannot be satisfied without exceeding the maximum allowed load of the system, the server suspending the request and invoking a recovery action.

2. The method of claim 1 wherein the evaluating step includes; the server determining the amount of electrical power needed to satisfy the request, by means of checking a look-up table containing historical power usage data of each client.

3. The method of any preceding claim wherein the evaluating step includes: the client sending information to the server on the amount of electrical power needed to satisfy the request.

4. The method of any preceding claim wherein recovery action includes the refusal of the request.

5. The method of any preceding claim wherein recovery action includes : issuing an alert signal to the user; responsive to a modification on any of the electrical power consuming elements controlled by the plurality of clients which modifies the total system usage, re-evaluating the request; if the request can be satisfied without exceeding the maximum allowed load, granting the requested electrical power.

6. The method of any preceding claim wherein the clients include a power switch which is activated by the server when the request is satisfied.

7. The method of any preceding claim wherein the clients communicate with the server by means of conveyed waves.

8. The method of any preceding claim wherein each client has a unique identifier which is communicated to the server when a request for electrical power is sent to the server.

9. A computer program for performing the method of any preceding claim when the computer program is executed on a data processing system.

10. A service for performing the method of any claim from 1 to 8.

11. A system including means for performing the steps of the method of any claim from 1 to 8.