Thermostat with power stealing delay interval at transitions between power stealing states

• US 8,511,577 B2
• Filed: 08/31/2012
• Issued: 08/20/2013
• Est. Priority Date: 02/24/2011
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.), OneID Inc.
• Original Assignee: Nest Labs Incorporated (Alphabet Inc.)
• Inventors: Warren, Daniel Adam, Satterthwaite, Edwin H. Jr., Smith, Ian C.
• Primary Examiner(s): Tyler, Cheryl J
• Assistant Examiner(s): Bradford, Jonathan
• Application Number:
  US13/601,574
• Publication Number:
  US 20120325919A1
• Time in Patent Office: 354 Days
• Field of Search: 236/1.C, 236/91.D, 236/91.G, 236/91.R, 236/94, 700/276, 307/43, 307/66, 307/125, 307/130, 307/131
• US Class Current: 236/1.C
• CPC Class Codes: F24F 11/30 for purposes related to the operation of the system, e.g. for safety or monitoring
• CPC Class Codes: F24F 11/46 Improving electric energy efficiency or saving
• CPC Class Codes: F24F 11/523 for displaying temperature data
• CPC Class Codes: F24F 11/526 giving audible indications
• CPC Class Codes: F24F 11/56 Remote control
• CPC Class Codes: F24F 11/58 using Internet communication
• CPC Class Codes: F24F 11/61 using timers
• CPC Class Codes: F24F 11/66 Sleep mode
• CPC Class Codes: F24F 11/88 Electrical aspects, e.g. circuits
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2120/00 Control inputs relating to users or occupants
• CPC Class Codes: F24F 2120/14 Activity of occupants
• CPC Class Codes: G05D 23/19 characterised by the use of electric means G05D23/1393 takes precedence
• CPC Class Codes: G05D 23/1902 characterised by the use of a variable reference value

Abstract

A thermostat includes a plurality of HVAC (heating, ventilation, and air conditioning) wire connectors including a connection to at least one call relay wire. The thermostat may also include a powering circuit, including a rechargeable battery, which is configured to provide electrical power to the thermostat by power stealing from a selected call relay wire. The power stealing may include an active power stealing mode, in which power is taken from the same selected call relay wire that is used to call for an HVAC function, and an inactive power stealing mode in which, in which no active call is being made. The powering circuit may be configured to substantially suspend (or at least reduce the level of) power stealing for at least a first time period following each transition of the thermostat from between operating states.

Claims

1. A thermostat, comprising:

a plurality of HVAC (heating, ventilation, and air conditioning) wire connectors configured to receive a plurality of HVAC wires, wherein;

the plurality of HVAC wires is associated with an HVAC system; and

the plurality of HVAC wires comprises at least one call relay wire;

a powering circuit, including a rechargeable battery, that is coupled to the plurality of HVAC wire connectors, the powering circuit being configured to provide electrical power to the thermostat by power stealing from a selected one of said at least one call relay wires, wherein;

said power stealing comprises an active power stealing mode in which power is taken from said selected call relay wire while the thermostat is in a first operating mode in which the thermostat is actively calling for an HVAC function associated with said selected call relay wire,

said power stealing further comprises an inactive power stealing mode in which power is taken from said selected call relay wire while the thermostat is in a second operating mode in which the thermostat is not actively calling for said HVAC function associated with said selected call relay wire,

said powering circuit is configured to substantially suspend said power stealing for at least a first time period immediately following;

(i) each transition of the thermostat from said first operating mode to said second operating mode, and

(ii) each transition of the thermostat from said second operating mode to said first operating mode, and

said powering circuit provides said electrical power to the thermostat during said times of substantially suspended power stealing at least in part by drawing power from said rechargeable battery.

2. The thermostat of claim 1, wherein the first time period is about 5 seconds.

3. The thermostat of claim 2, wherein said suspended power stealing comprises stealing a first amount of power that is very small or negligible in comparison to a second amount of power that is stolen during times when said power stealing is not suspended.

4. The thermostat of claim 3, wherein said suspended power stealing comprises reducing a current associated with the power that is stolen to less than approximately 1 mA.

5. The thermostat of claim 3, wherein said power stealing is suspended for between approximately 5 seconds to approximately 20 seconds for each said transition from said first operating mode to said second operating mode.

6. The thermostat of claim 2, wherein said power stealing is suspended for between approximately 40 seconds to approximately 160 seconds for each said transition from said second operating mode to said first operating mode.

7. The thermostat of claim 1, wherein during said active power stealing mode a connection between (i) said selected call relay wire and (ii) a corresponding return HVAC wire is disconnected for periods lasting at least a second time period, wherein the second time period during which said connection is disconnected is substantially less than a third time period during which said connection is connected during said active power stealing mode.

8. The thermostat of claim 1, wherein the thermostat is further configured to:

detect whether a common “

C”

wire is inserted in the thermostat;

provide, if the common “

C”

wire is inserted in the thermostat, electrical power for use by the thermostat by taking power from said common “

C”

wire at all times of operation and without any suspensions thereof associated with transitions between said first and second operating modes;

provide, if no common “

C”

wire is inserted in the thermostat, electrical power for use by the thermostat by taking power from said selected call relay wire by said power stealing.

9. The thermostat of claim 8, wherein the thermostat is further configured to:

select a “

Y”

cooling call wire as the selected call relay wire from which power is taken by said power stealing if (i) no common “

C”

wire is inserted in the thermostat, and (ii) a “

Y”

cooling call wire is inserted in the thermostat; and

select a “

W”

heating call wire as the selected call relay wire from which power is taken by said power stealing if (i) no common “

C”

wire is inserted in the thermostat, (ii) no “

Y”

cooling call wire is inserted in the thermostat, and (iii) a “

W”

heating call wire is inserted in the thermostat.

10. A method of controlling an HVAC (heating, ventilation, and air conditioning) system using a thermostat, the method comprising:

selecting a call relay wire from a plurality of HVAC wire connectors configured to receive a plurality of HVAC wires, wherein;

the plurality of HVAC wires is associated with an HVAC system; and

the plurality of HVAC wires comprises at least one call relay wire;

providing electrical power to the thermostat by power stealing from said selected call relay wire, wherein;

said power stealing comprises an active power stealing mode in which power is taken from said selected call relay wire while the thermostat is in a first operating mode in which the thermostat is actively calling for an HVAC function associated with said selected call relay wire,

said power stealing further comprises an inactive power stealing mode in which power is taken from said selected call relay wire while the thermostat is in a second operating mode in which the thermostat is not actively calling for said HVAC function associated with said selected call relay wire;

detecting transitions of the thermostat (i) from said first operating mode to said second operating mode, and (ii) from said second operating mode to said first operating mode;

substantially suspending said power stealing for at least a first time period immediately following each detected transition, wherein said electrical power is provided to the thermostat during said times of substantially suspended power stealing at least in part by drawing power from a rechargeable battery.

11. The method of claim 10, wherein said first time period is at least about 5 seconds.

12. The method of claim 11, wherein said power stealing is substantially suspended for approximately 10 seconds when the thermostat transitions from said first operating mode to said second operating mode, and wherein said power stealing is substantially suspended for approximately 75 seconds when the thermostat transitions from said second operating mode to said first operating mode.

13. The method of claim 10, wherein said substantially suspending said power stealing comprises reducing a downstream current level associated with the power stealing to less than approximately 5 mA.

14. The method of claim 10, wherein said substantially suspending said power stealing comprises completely suspending said power stealing by reducing a downstream current level associated with the power stealing to approximately 0 mA.

15. The method of claim 10, further comprising:

detecting whether a common “

C”

wire is inserted in the thermostat;

providing, if the common “

C”

wire is inserted in the thermostat, electrical power for use by the thermostat by taking power from said common “

C”

wire at all times of operation and without any suspensions thereof associated with transitions between said first and second operating modes;

providing, if no common “

C”

wire is inserted in the thermostat, electrical power for use by the thermostat by carrying out said selecting a call relay wire and said power stealing from said selected call relay wire.

16. A thermostat, comprising:

a first HVAC wire connector configured to receive a first HVAC call relay wire of an HVAC system, the HVAC system having at least two states of operation including an active state and an inactive state relative to the first HVAC call relay wire;

a powering circuit coupled to the first HVAC wire connector and configured to steal power from the HVAC system, the powering circuit comprising;

a rechargeable battery configured to store power stolen from the HVAC system; and

a control circuit configured to;

(i) determine whether the HVAC system is transitioning from the active state to the inactive state and, in response to a determination that the HVAC system is so transitioning, cause a power level that is stolen from the HVAC system to be reduced for a first time period; and

(ii) determine whether the HVAC system is transitioning from the inactive state to the active state, and in response to a determination that the HVAC system is so transitioning, cause the power level that is stolen from the HVAC system to be reduced for a second time period that is longer than said first time period.

17. The thermostat of claim 16, wherein:

the first time period is in the range of approximately 5 seconds to approximately 20 seconds; and

the second time period is in the range of approximately 40 seconds to approximately 160 seconds.

18. The thermostat of claim 16, wherein the active state of operation of the HVAC system comprises a heating function, and wherein the first HVAC wire connector is a “

W”

heating call relay wire connector.

19. The thermostat of claim 16, wherein the active state of operation of the HVAC system comprises a cooling function, and wherein the first HVAC wire connector is a “

Y”

cooling call relay wire connector.

20. The thermostat of claim 16, wherein the thermostat is further configured to:

detect whether a common “

C”

wire is inserted in the thermostat;

provide, if the common “

C”

wire is inserted in the thermostat, electrical power for use by the thermostat by taking power from said common “

C”

wire at all times of operation and without any power reductions thereof associated with transitions between said active and inactive states;

provide, if no common “

C”

wire is inserted in the thermostat, electrical power for use by the thermostat by taking power from the first HVAC call relay wire by said power stealing.