des brevets
`
`Europalsches
`Patentamt
`European
`Patent Office
`Office européen
`
`(11)
`
`EP 1 814 260 A2
`
`(12)
`
`EUROPEAN PATENT APPLICATION
`
`(43) Date of publication:
`01.08.2007 Bulletin 2007/31
`
`(51)
`
`Int CL:
`HOA4L 12/28 (2006.01)
`
`(21) Application number: 07009994.0
`
`(22) Dateof filing: 14.10.2005
`
`(84) Designated Contracting States:
`AT BE BG CH CY CZ DE DK EE ES FI FR GB GR
`HU IE IS IT LILT LU LV MC NL PL PT ROSESI
`SK TR
`
`Designated Extension States:
`AL BA HR MK YU
`
`(30) Priority: 14.10.2004 US 619400 P
`07.09.2005 US 714938 P
`
`(62) Document number(s) of the earlier application(s)in
`accordancewith Art. 76 EPC:
`05812413.2 / 1 800 438
`
`(71) Applicant: Lagotek Corporation
`Bellevue, WA 98009 (US)
`
`Inventors:
`(72)
`- Luskin, Eugene
`Issaquah
`Washington 98029 (US)
`
`
`
`¢ Kizhnerman, Vadim
`Kirkland, Washington 98034 (US)
`« Grach, Alexander
`Bothell, Washington 98012 (US)
`¢ Tcherkachine, Lev
`Redmond, Washington 98052 (US)
`
`(74) Representative: Whitlock, Holly Elizabeth Ann etal
`R GC Jenkins,
`26 Caxton Street
`
`London SW1H ORJ (GB)
`
`Remarks:
`
`This application wasfiled on 18-05-2007 asa
`divisional application to the application mentioned
`under INID code 62.
`
`(54)
`
`Distributed wireless home network and commercial electrical automation system
`
`A central controller is disclosed to enable home
`(57)
`and commercial automation for automatic, remote con-
`trol of a wide variety of lights, appliances, HVAC and
`other systems utilizing a wireless distributed network.
`The central controller preferably employs a standard
`
` LNZSNZ
`
`
`
`/
`
`CPU and embedded operating system software. Graph-
`ical and audio user interfaces can be implemented. Har-
`monic distortion due to non-linear AC loads are mitigated
`in single-phasecircuits through intelligent control of the
`loads and/or through intelligent complementary control
`of linear loads.
`
`T
`
`7
`r
`\
`/- CENTRAL
`CONTROLLER|
`
`B .
`
`WIRELESS
`CONTROLLER
`
`GOOR
`LOGK DEVICE,
`
`
`
`WIRELESS
`CONTROLLER
`c
`
`FIG. 3
`
`Printed by Jouve, 75001 PARIS (FR)
`
`EP1814260A2
`
`

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`EP 1 814 260 A2
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`Description
`
`Related Applications
`
`[0001] This application claims priority based on U.S.
`Provisional Patent Application Serial No. 60/619,400,
`filed October 14, 2004; and based on U.S. Provisional
`Patent Application Serial No. 60/714,938, filed Septem-
`ber 7, 2005. Both of said provisional applications are
`hereby incorporated herein by this reference.
`
`Copyright Notice
`
`[0002] © 2005 Lagotek Corporation. A portion of the
`disclosure of this patent document contains material that
`is subject to copyright protection. The copyright owner
`has no objection to the facsimile reproduction by anyone
`of the patent document or the patent disclosure, as it
`appears in the Patent and Trademark Office patent file
`or records, but otherwise reserves all copyright rights
`whatsoever. 37 CFR § 1.71(d).
`
`Technical Field
`
`[0003] The invention pertains to control systems for
`controlling various electrical loads, apparatus and sys-
`temsin the context of home and commercial automation,
`with particular focus on improvements in user conven-
`ience, energy efficiency and reliability.
`
`Background of the Invention
`
`[0004] Home automation heretoforeis either very lim-
`ited, to basic tasks such as remote control of light dim-
`mers and switches, or it involves complicated, expensive,
`custom hardware and software The known home auto-
`
`mation systems haveverylimited "intelligence" and awk-
`ward interfaces. Simple wireless modulesfor lights and
`household appliances are commercially available from
`Intermatic Incorporated of Spring Grove, IL. See www.in-
`termatic.com. Other wireless light modules including
`dimmers are available from Lutron and Zwave. It is well
`
`known that harmonic interference on AC power lines
`causes heat
`loss inefficiencies, and undue wear on
`equipment such as transformers. Harmonics are caused
`by non-linear loads, such as typical light dimmers, be-
`cause they actively switch the power on and off to adjust
`the light level, as distinguished from a passive regulator
`such as a potentiometer or rheostat which, although re-
`sistive and therefore linear, is highly energy inefficient.
`[0005]
`Passive solutions, such asfilters, are known for
`reducing harmonic distortion, but they have limitations
`and also dissipate energy. Active solutions have been
`developed for reducing harmonicsin 4-wire, 3-phase sys-
`tems, as taught in U.S. Pat. No. 5,568,371 to Pitel et al.
`That solution, however, is not applicable to the usual sin-
`gle-phase household circuit. Moreover, Pitel et al. de-
`scribe an activefilter that requires substantial hardware
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`housed in a separate box.
`[0006] The need remains for improvements in home
`and commercial automation to reduce costs, enable a
`wide variety of applications without custom hardware de-
`velopment, improve user convenience and comfort, as
`well as reliability.
`
`Summary
`
`[0007] Thepresent invention is directed in various as-
`pects to a variety of improvements in home or commercial
`automation and energy savings. Additional aspects and
`advantageswill be apparent from the following detailed
`description of preferred embodiments, which proceeds
`with reference to the accompanying drawings.
`
`Brief Description of the Drawings
`
`Fig. 1A is a front plan view illustrating replace-
`[0008]
`ment of a conventional light switch with a central control-
`ler.
`
`Fig. 1 Bis an exploded viewillustrating a central
`[0009]
`controller sized and arranged for installation in lieu of a
`conventional light switch or outlet in a standard home
`electrical box.
`
`Figs. 2A-2Cillustrate examples of front panel
`[0010]
`display content of a central controller.
`[0011]
`Fig. 3 is one example of a home automation
`networkillustrating application of various componentsin-
`cluding integrated as well as external wireless control-
`lers.
`
`Fig. 4 is a functional hardware block diagram
`[0012]
`of one example of a central controller consistent with the
`presentinvention.
`[0013]
`Fig. 5 is a simplified residential floor plan illus-
`trating an example of an HVAC application of the inven-
`tion for improved convenience and energy efficiency.
`[0014]
`Fig. 6 is a simplified schematic diagram illus-
`trating an asymmetric biprocessor architecture of a cen-
`tral controller in accordance with one aspect of the in-
`vention.
`
`Fig. 7A showslinear loads in a single-phase
`[0015]
`A.C. power circuit.
`[0016]
`Fig. 7B shows the essentially sinusoidal elec-
`trical current waveform in the circuit of FIG. 7A.
`
`FIG. 8A illustrates a plurality of non-linear loads,
`[0017]
`here conventional light dimmers each set to 33% bright-
`ness.
`
`FIG. 8B showsthe resulting non-linear electri-
`[0018]
`cal current waveform through the loads of FIG. 8A.
`[0019]
`FIG. QA illustrates a system in accordancewith
`one embodiment of the present invention for normalizing
`non-linear loading in a single-phase power circuit to re-
`duce harmonic distortions.
`
`FIG. 9B showsthe resulting load current using
`[0020]
`intelligent controllers for phase control to linearize the
`load.
`
`[0021]
`
`FIG. 10 illustrates a system arranged for regu-
`
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`lating a resistive load so as to compensate for one or
`more non-linear loads in the same circuit.
`
`ployed for various electrical and mechanical tasks, as
`further described below.
`
`In accordance with the present invention, vari-
`[0028]
`ous embodiments of a central controller are disclosed.
`
`The central controller preferably is wireless, but it can be
`hardwired for communications. Other particulars of pre-
`ferred embodimentsare asfollows.
`
`[0029] Basically, the central controller is a microproc-
`essor-based electronic device to enable home or com-
`
`mercial automation functionality. It is the main hardware
`component of a home automation network, although as
`noted there can be more than one central controller. The
`
`central controller preferably executes at least one indus-
`try standard operating system, so that it provides an
`“open platform" for third party application software de-
`velopers. Some of those applicationswill include lighting
`(both interior and exterior of a structure), HVAC (heating,
`ventilation and air conditioning), security (audio, motion
`detecting, video surveillance, etc.), entertainment, ener-
`gy savings, etc. Implementation of any desired applica-
`tion can be accomplished with suitable programming and
`applying the invention as described herein.
`[0030]
`In one preferred embodiment, the central con-
`troller is sized and arrangedtofit inside of a standard
`household electrical box of the type that would commonly
`house aconventional light switch or outlet. A small central
`controller could be fit into a single switch box, while a
`two-gang, three-gang or larger box can accommodate a
`larger central controller and a correspondingly larger dis-
`play panel -further described below. FIG. 1A illustrates
`the front appearanceof a light switch replaced by a cen-
`tral controller in accordance with an embodimentof the
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`FIG. 11 showsillustrative waveforms and com-
`[0022]
`munication paths for the system of FIG. 10.
`[0023]
`FIG. 12 shows a waveform generated by the
`central controller for normalizing the circuit of FIGS. 10
`and 11 by regulating the resistive load.
`
`Detailed Description of Preferred Embodiments
`
`[0024] Nomenclature Note: In the provisional applica-
`tion, we used the term "Control Panel" to refer to "micro-
`processor based electronic device, capable of running
`operating systems which supports the wireless protocol,
`graphical user interface, touch screen functionality ...".
`(Provisional page 3.) In the present application, we will
`instead use the term "central controller"to refer to various
`
`devices and embodiments functionally similar to what
`waspreviously called the "Control Panel". This is to avoid
`confusion as the typical Central Controller, in accordance
`with some embodiments of the invention, will itself in-
`clude a front panel or control panel that provides an in-
`terface to the controller.
`
`[0025] Thus "control panel" will be used herein con-
`sistent with its ordinary meaning. For example,
`in one
`preferred embodiment, a central controller is disposed in
`a standard electrical box, andthe front panel of the central
`controller is installed over it, similar to a conventional light
`switch cover plate. The term "central controller" is not
`intended to imply that only one central controller can be
`usedin a given installation such as a home or office. To
`the contrary, in most cases, a plurality of central control-
`lers will be deployed so as to form a distributed or mesh
`network, communicating with one another as further de-
`scribed later. That said, a single central controller can be
`used in smaller applications.
`[0026] Theprovisional application also defined a"wire-
`less controller" as, “any chip implementing one or more
`of several radio interfaces to allow communication over
`
`other central controllers in the same network, and for
`communications with various other components, some
`of which are "controllers" (but not central controllers). The
`central controller(s) is where the user(s) mainly interface
`with the system. Other controllers, such as dimmers, re-
`spond to commands from a central controller to operate
`lights or other electrical loads. Controllers can be de-
`
`invention. FIG. 1 Bis an exploded view showing in more
`detail how acentral controller can be deployed in a stand-
`ard electrical box. The household wiring (available in the
`box) provides power for the central controller, although
`it can be battery powered or have battery backup.
`[0031] The front panel of the central controller, which
`is removable for service and generally covers the central
`controller, preferably includes a display screen, which
`wirelesslinks with various communication networks sup-
`preferably comprises a touch-sensitive area, at least in
`porting the wireless protocol." This may be confusing,
`part, for user input by touching an icon or other textual
`both internally and because the typical central controller
`described herein in some embodimentsis correctly char-
`or graphic indicia to make a selection or adjustment.
`acterized as wireless. In this document, wewill use "wire-
`[0032] Thedisplay/ touch screen can be employed by
`less transceiver" to refer to apparatus that implements
`suitable programming to provide an effective graphical
`
`communication overawireless channel, which may com- user interface. In a simple example, one screen display
`prise an accesspoint, for example in the case of 802.11
`(not shown) can be used to emulate a conventional light
`switch or dimmer control. This is a useful default value,
`implementations, or not, as in the case of Bluetooth or
`other ad hoc wireless protocols.
`say for a bedroom, where the user commonly enters the
`[0027] The central controller preferably includes one
`room and expects a light switch in the usual location in-
`or more wireless transceivers for communication with
`side the door. A central controller can replace the light
`switch in that box, and the default screen display can
`look like a light switch, and indeed function to turn the
`light off and on, responsive to a user pressof the touch
`screen.
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`[0033] Referring again to FIG. 2A, it illustrates certain
`preferred features of the front panel. For example, the
`panel includes a few "hard" buttons -actual physical but-
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`embodiments, a central controller in accordancewith the
`tons, that can be operated at any time without using the
`present invention executes application software and in-
`touch screen. These are labeled for illustration as "Ap-
`cludes wireless transceivers that are compatible with
`plication" and "Select". Continuing the bedroom exam-
`these existing modules so as to include them in the new
`ple, after the default display is used to turn on the light,
`the user may press "Application" to see a list or set of
`network. More sophisticated controllers, called "intelli-
`icons representing applications currently available to her
`gent controllers," are discussed later with regard to man-
`at that central controller. She may select "Audio" by
`aging harmonics caused by non-linear loads.
`[0037]
`FIG. 3 alsoillustrates a wireless controller "C"
`pressing the corresponding icon,
`in which case the
`coupled to an appliance such as a stove. The central
`screen display changes again to present the audio player
`controller can check to ensure that the stove is notleft
`controls of FIG. 2A. By touching the screen where the
`on when no one is at home. Motion or thermal detectors,
`pause, play, etc buttons are shown, the user can con-
`veniently operate the audio system from the central con-
`as part of the network, can be used to determine whether
`people are at home. The same sensors are conveniently
`troller. This is accomplished by a wireless controller that
`used for HVAC/ comfort control, automated lighting ap-
`is inside or coupled to the audio equipment to receive
`plications, security, etc. In that regard, a door lock device
`corresponding commandsfrom the central controller.
`is shown in FIG. 3 as well. Here, the wireless transceiver
`[0034] Note the top of the screen display preferably
`capability is integrated into the door lock device itself; a
`showsthe location of the central controller, for example
`separate wireless controller is not required. This device
`"Room Two" (FIG. 2A), "Living Room"(FIG. 2B), "Kitch-
`can be used to remotely lock or unlock the door, but also
`en" (FIG. 2C) etc. The display preferably also includes a
`to report its status, open, closed, locked, to the security
`screen number where a given function requires more
`than one screen display. For example, in the living room,
`application software executing on the central controller
`
`the lighting control screens spanatotal of six screens, in some embodiments of the invention. Various security
`with screen "2/6" shown in FIG. 2B. These principles of
`algorithms can be used to secure the wireless commu-
`graphical user interface can be applied to other applica-
`nications in the network and prevent unauthorized intru-
`sion.
`tions as well. In general, the central controller can interact
`with any electrical apparatus or system within the local
`network. The local network comprises one or more cen-
`tral controllers together with one or more, preferably
`many, controllers that communicate with the central con-
`troller and interact with various apparatus coupled to
`those controllers, such as audio, video, HVAC equip-
`ment, lighting, etc.
`[0035]
`Some of these featuresare illustrated in FIG. 3
`-a simplified network diagram. In this example, a central
`controller implements wireless communications, shown
`by dashedlines, with various components of the network.
`For example, a wireless controller "A" is connected toa
`motorized damper for HVAC control. It adjusts the damp-
`er in response to commandsfrom the central controller.
`Another wireless controller "B" is connected to a video
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`FIG. 4 is a simplified hardware block diagram
`[0038]
`of one example of a central controller consistent with the
`present invention. Interconnections among the various
`components are omitted to avoid obscuring the drawing.
`Preferably, the CPU is an industry standard off-the-shelf
`microprocessor, along with internal and or external mem-
`ory as appropriate, including both volatile and non-vola-
`tile memory such as flash memory. Preferably the CPU
`is provided with at least one standard embeddedoper-
`ating system such as Windows CE®, Linux Embedded,
`QnXor the like.
`
`Inthe example illustrated, sensors are provided
`[0039]
`for sensing local ambient temperature, proximity (of a
`person), ambient light level, and so on. A microphone
`enables voice commandinputs (in cooperation with voice
`recognition software stored in the memory and executa-
`ble on the CPU). A speaker enables audible alarms,
`warnings or other announcements. A service connection,
`for example a standard connector such as an USB port
`can be provided for diagnostics, software loading, etc.
`Alternatively, the wireless transceiver can be used for
`communication with acomputer or similar device for such
`functions. Other embodiments may have more of fewer
`sensors, inputs or outputs. Additional details of various
`specific embodiments of the invention will be within the
`design capabilities of persons skilled in electronics and
`microprocessor applications in view of the present dis-
`closure. A alternative biprocessor architecture that incor-
`porates the secondary processor is describedlater.
`[0040]
`FIG. 5 is a simplified residential floor plan to
`illustrate selected aspects of HVAC control using the
`present invention. Here, each room illustrated includes
`a motion or proximity sensor "M" and a temperature sen-
`
`camera for security surveillance. The controller can ad-
`just the camera in response to commandsfrom the cen-
`tral controller, as well as communicate video data to the
`central controller. Surveillance software in the central
`
`controller may include, for example, image recognition
`software for detecting an intruder outside the premises
`by analyzing the captured video data. A wireless hub can
`be used to interface multiple appliances to a central con-
`troller where they are not coupled toit directly.
`[0036] Wireless controllers may vary in their particular
`features and characteristics as necessary. A simple, low
`cost controller, forexample, can be used merely to switch
`a light or outlet on and off responsive to remote com-
`mands. Simple wireless modulesfor lights and house-
`hold appliances are commercially available from Inter-
`matic Incorporated of Spring Grove, IL. See www. inter-
`matic.com. Other wireless light modules including dim-
`mers are available from Lutron and Zwave. In preferred
`
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`sor"T". These may be "standalone" remote sensor units,
`with the ability to communicate with a central controller.
`Or, one or more of them mayitself be a local central
`controller in that room. Either way, comfort control soft-
`ware executing on the central controller can determine
`which rooms are occupied, as well as the current tem-
`perature of each room. Based on that information, it can
`adjust each local room HVAC damper(s) to optimize com-
`fort while minimizing energy consumption. The system
`can also be used to control the HVAC system itself as
`part of this process.
`[0041]
`To briefly summarize this section, the invention
`enables a user to conveniently: control any wirelesslight
`switch in any room; control any wireless power outlet;
`control any other electrical appliance which can be con-
`trolled via wireless protocol (coffee makers, rice makers,
`floor lamps, pool/tub electrical systems, smoke detec-
`tors, electrical locks, garage openers, etc), i.e. applianc-
`es that have integrated or "built-in" wireless control ca-
`pability; and access media stored on the wireless server
`oron any other media storage device connecteddirectly
`or indirectly by the wireless protocol to other system com-
`ponents. Of course, some embodimentsof the invention
`will implement fewer than all of these features; they are
`not all required by the invention. The key point is that the
`central controller and distributed network described here-
`
`in can be used in myriad ways, without significant hard-
`ware changes or added expense, because this system
`is fundamentally application software driven.
`[0042] Additional functionality can include: monitor vid-
`eo from any video camera or other video signal source
`connected directly or indirectly by the wireless protocol
`to other system components; access settings and control
`the HVAC system in the household; have voice commu-
`nication via the phone or inside the household between
`two or more central controller's; operate electrical devic-
`es which support infrared remote controls via the device
`which is equipped with the wireless controller and infra-
`red emitter; access, control, query any other electronic
`devices via wireless protocol or infrared sequences.
`[0043]
`All the foregoing functions of the central con-
`troller can be accessedwith the touch screen or by voice
`command, or automatically (under software control) in
`responseto sensor inputs, time or other trigger conditions
`or acombination of trigger conditions. In a preferred em-
`bodiment, any particular setting or parameter of the sys-
`tem can be used as a part of a saved profile. Any profile
`can be selected by user or automatically (according to
`schedule, day light, etc.).
`[0044] The user interface of the central controller is
`designed to accommodate people's habit of entering a
`room and switching the light on. To do so, the user inter-
`face in one embodiment implementsthe "default switch"
`virtual button. This graphic button is displayed as the de-
`fault screen display on the cc after a short timeout period
`following the last active user input. Any combination of
`the parameters or settings can be controlled by the "de-
`fault button". Thus, for example, where each bedroom
`
`the occupant need
`has a central controller installed,
`merely touch the central controller panel once upon ar-
`rival to set lighting, audio, heat, etc. as determined by
`that user's personalprofile. Profiles can be usedin indi-
`vidual spaces and or network-wide. Some illustrative
`home-wideprofiles are as follows:
`
`Profile 1: No one home
`
`Lighting: Lights off except, after dark, ON bath-
`[0045]
`room #1 and bedroom #3 andhall #2.
`
`Security: Full ON after one minute for exit, check door
`locks, commence video surveillance.
`Comfort: Lower all living spaces to 62-degreesF.
`Entertainment: Off
`
`Profile 2: Home: Commencing at 4:00 pm on weekdays
`
`Lighting: Lights ON after dark, OFF bathroom
`[0046]
`#1 and all bedrooms; ON living room default settings
`Security: door and window chimes only, discontinue vid-
`eo surveillance.
`
`Comfort: Raise all living spaces to 72-degreesF.
`Entertainment: Audio enabled, download daily news
`feed.
`
`Profile 3: Sunday morning; etc....Profile 4: Sun-
`[0047]
`day afternoons, etc.
`[0048]
`Profile 5: short vacation, and so on. Profiles are
`created under software control and stored in non-volatile
`
`memoryin the appropriate central controller.
`
`Asymmetrical biprocessor architecture
`
`[0049] Anasymmetrical biprocessor architecture is op-
`tional but preferred to improvethe reliability, availability
`and serviceability of home or commercial automation
`systems such as those described above.
`[0050] Modem home automation system contain hun-
`dreds electronic components and hundred of thousands
`to millions lines of lines of software code. The failure of
`
`a single component (hardware and software) may render
`the system completely unusable which is unacceptable
`for home automation applications. There is a need for
`reliable, available and easily services and updated sys-
`tem.
`
`[0051] There aretwo main contributing factors thatcan
`lead to failure in a home automation system:
`
`1. Software errors. Bugs occurs because it’s imprac-
`ticable to provide 100%testing of large programs.
`2. Main processor has alot of dependencies on other
`electronic components. Failure of any of these com-
`ponents as failure of CPU itself makes the whole
`system unworkable. Also, the typical system con-
`tains fragile componentslike a touch screen, so there
`is always a risk that this screen can be broken, and
`even when formally the system is alive, it becomes
`verydifficult to use it.
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`[0052] Wepropose anew design for reliable home au-
`tomation systems using two different processors. As de-
`scribed above, a home automation system comprises at
`least one central controller. It may used several of them.
`In many cases, all of the central controllers will be the
`same - to lower cost and simplify installation of a distrib-
`uted network. We propose that a central controller com-
`prise at least two different processors.
`[0053] Referring now to FIG. 6, a simplified schematic
`diagramillustrates one example of an asymmetric biproc-
`essor architecture of a central controller in accordance
`
`with one aspectof the invention. Here, a ProcessorA is
`a main controller which performsthe full-scale function-
`ality of the system, optionally including "nice-to-have" but
`non-essential features like speech recognition, a graph-
`ical user interface, position sensors, etc. Preferablyit is
`a relatively fast processor, which is connected to external
`memory (ROM and or RAM) as described earlier. On the
`contrary, the Processor B is relatively slow embedded
`microcontroller, with few dependencies on external com-
`ponents. It has three main functions:
`
`1. Verify that the program in Processor A is alive and
`is performing normally (watchdog functionality).
`2.
`In the case offailure in Processor A, it switches
`the main controlling circuits of periphery on itself and
`performing the basic functionality (e.g., turning the
`lights/electrical loads on/off).
`3. Log all system failures in a non-volatile memory
`journal.
`
`[0054] As shown in the figure, a switch controlled by
`Processor B is used to take over interaction with all pe-
`ripheral devices and interfaces in the event that Proces-
`sor B detects a failure of Processor A. Monitoring is im-
`plemented via the communication link shown. The soft-
`ware for Processor B preferably contains relatively few
`-only several hundredlines of code, so that the algorithms
`can be 100% tested.
`
`Accordingly, the risk of a software bug in Processor B is
`much (by the inventors’ estimate better than 100 times)
`lower.
`
`10
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`15
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`20
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`25
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`30
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`35
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`40
`
`ments, we seek to normalize electrical loads associated
`with dimming light systems and other non-linear electrical
`loads. Such normalization reduces heat dissipation in
`distribution transformers and the harmonic distortion cre-
`
`ated by non-linear loads that are typical in most residen-
`tial and commercial electrical systems. In some embod-
`iments, energy savings are accomplished by leveraging
`a distributed home automation network.
`
`[0057] Thus one aspect of the present invention en-
`hances distributed wireless automation systems by in-
`troducing system level components that reduce harmon-
`ic distortion and heat that can cause energy inefficiencies
`and electrical infrastructure failures. The sources of these
`
`inefficiencies are lighting systems that utilize dimming
`controls, computer and pulse power supplies, televisions
`and other non-linear loads.
`
`[0058] One aspect of the invention is directed to re-
`ducing K-factor and associated energy lossesbyintelli-
`gent control of dimmedelectrical loads by the distributed
`home automation network. The electrical load in a typical
`residential location is non-linear and consequently it gen-
`erates harmonic currents -mainly odd harmonicsin the
`case of single-phase nonlinear loads. These currents are
`usually dissipated in distribution transformers resulting
`in overheating and energy losses. The harmonic distor-
`tions are quantitatively described by a"K-Factor," defined
`as
`
`K-Factor = S(lh)2h2
`
`wherelh is the load current at harmonic h, expressedin
`a per-unit basis such that the total RMS current equals
`one amp, i.e., S(Ih)2 = 1.0
`[0059] K-Factoris a weighing of the harmonic load cur-
`rents according to their effects on transformer hating, as
`derived from ANSI/IEEE C57.110. A K-Factor of 1.0 in-
`
`dicates a linear load (no harmonics). The higher the K-
`Factor, the greater the harmonic heating effects. Figure
`7A shows linear load when K-Factor = 1 and thermal
`losses in the distribution transformer are low. FIG. 7B
`
`showsthe essentially sinusoidal electrical current wave-
`[0055] Given that the number of dependent compo-
`form through the load of FIG. 7A. However, many of the
`nents is smaller in this design, the possibility of hardware
`modem electronic loads increasingly found in residential
`failure is lower as well (it is proportional to the number of
`and commercial buildings are nonlinear-dimmed light,
`dependent components and pin count of the processor).
`computers, pulse power supplies, etc. The typical K-fac-
`This contrasts with a simple "mirroring" or backup
`tor value for the office is usually from 4 to 9 which corre-
`scheme in which a second processor, identical to Proc-
`spondsto the 15 - 20%increase in the heat losses.
`essor A,
`is deployed as a backup. That approach im-
`50
`
`proves reliability, but at higher cost, and with inferior re- [0060]_FIG. 8A illustrates a plurality of non-linear loads,
`sults.
`here conventional light dimmers, set to 1/3 brightness,
`in a single-phase power circuit. FIG. 8B showsthe re-
`sulting non-linear electrical current waveform through the
`load of FIG. 8A. This waveform has substantial harmonic
`
`Energy Savings Techniques
`
`45
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`55
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`In this section we describe new methods and
`[0056]
`systems for saving energy in residential and commercial
`facilities, especially those where non-linear loads create
`harmonic distortions on the supply.
`In some embodi-
`
`distortion, meaning that there is substantial current flow
`in the third and subsequent odd harmonics of the line
`fundamental frequency (60 Hz.). As noted earlier, this
`scenario leads to thermal losses, equipment wear, and
`
`

`

`14
`
`EP 1 814 260 A2
`
`12
`
`"normalizes" the harmonic distortion that results from
`
`voltage waveform degradation in the power supply sys-
`tem.
`
`im-
`In accordance with the present invention,
`[0061]
`proved power control is implemented to remedythis sit-
`uation, without sacrificing operational functionality in any
`noticeable way. Two schemesare presented; regulating
`individual non-linear loads so they workbetter together;
`and using the presence ofa linear load to normalize the
`overall system current flow.
`[0062]
`First, we propose to use a distributed network
`of sensor and dimmers (power regulators) to reduce har-
`monicdistortions and associated heat losses. Referring
`now to FIG. 9A, three dimmers are again shown as loads.
`Here, a current sensor labeled "A" is deployedin the cir-
`cuit to measure the current waveform.
`It functions to
`
`10
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`15
`
`non-linear loading of the types described above. A resi-
`dential electric water heater is a good example of a linear
`(resistive) load. Importantly,
`it will function with a non-
`linear supply.
`[0066]
`FIG. 10 illustrates one embodiment of this sec-
`ond solution. Here, a current sensor "A" is used, as be-
`fore, to capture the electrical current waveform in the
`system. It sends the waveform data to acentral controller
`"B", preferably by a wireless channel. In both the first and
`second solutions, the current sensor (load current wave-
`form) data should be updated periodically. This update
`can be scheduled, pushed, polled or any other conven-
`ient mechanism. Advantageously, in a home automation
`network context,
`the applicatio