Power management in single circuit HVAC systems and in multiple circuit HVAC systems

• US 9,448,567 B2
• Filed: 03/15/2013
• Issued: 09/20/2016
• Est. Priority Date: 11/19/2010
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Google Inc. (Alphabet Inc.)
• Inventors: Erickson, Grant M, Warren, Daniel Adam, Fiennes, Hugo, Dutra, Jonathan Alan, Bell, David, Fadell, Anthony Michael, Rogers, Matthew Lee, Smith, Ian C., Satterthwaite, Edwin H. Jr., Mucignat, Andrea, Palmer, Joseph E.
• Primary Examiner(s): Kasenge, Charles
• Application Number:
  US13/835,860
• Publication Number:
  US 20130221117A1
• Time in Patent Office: 1,285 Days
• Field of Search: 700/276, 700/278, 236/1.C, 236/51, 236/91.R
• US Class Current: 1/1
• 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 11/56 Remote control
• CPC Class Codes: F24F 11/58 using Internet communication
• CPC Class Codes: F24F 11/61 using timers
• CPC Class Codes: F24F 11/63 Electronic processing
• CPC Class Codes: F24F 11/88 Electrical aspects, e.g. circuits
• CPC Class Codes: F24F 2110/10 Temperature
• CPC Class Codes: F24F 2120/14 Activity of occupants
• CPC Class Codes: G05B 2219/2614 HVAC, heating, ventillation, climate control
• 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 for receiving a plurality of HVAC control wires corresponding to an HVAC system. The thermostat also includes a thermostat processing and control circuit operative to at least partially control the operation of the HVAC system and a powering circuit coupled to the HVAC wire connectors and configured to provide an electrical load power to the thermostat processing and control circuit. The thermostat includes circuitry and methods for maximizing efficiency of energy harvested from the HVAC system connected to the thermostat, and depending on which system is connected to the thermostat, different power schemes can be implemented in order to obtain power from the HVAC system.

Claims

1. A method for controlling a HVAC (heating, ventilation, and air conditioning) system, the method implemented in a thermostat, the method comprising:

determining one of a plurality of different HVAC wiring schemes for the thermostat, the HVAC wiring schemes comprising a single circuit system having no common wire, a multiple circuit system having no common wire, or a common wire system; and

implementing a power scheme based on the determined HVAC wiring scheme, wherein;

if the determined HVAC wiring scheme is the single circuit system, the power scheme uses active and inactive power stealing on the single circuit system;

if the determined HVAC wiring scheme is the multiple circuit system, the power scheme only uses inactive power stealing on a non-enabled circuit within the multiple circuit system;

or

if the determined HVAC wiring scheme is the common wire system, the power scheme uses neither active power stealing nor inactive power stealing.

2. The method according to claim 1, wherein active power stealing comprises momentarily opening a closed contact during an enabled phase of the single circuit system.

3. The method according to claim 2, wherein the contact is closed during a majority of each duty cycle when the single circuit system is in the enabled phase.

4. The method according to claim 1, wherein active power stealing comprises receiving power from an enabled HVAC relay circuit in a manner that does not untrip the enabled HVAC relay circuit.

5. The method according to claim 1, wherein inactive power stealing comprises receiving power from a non-enabled HVAC relay circuit in a manner that does not trip the non-enabled HVAC relay circuit.

6. The method according to claim 1, wherein the thermostat comprises a plurality of HVAC wire connectors operative to receive a plurality of HVAC wires corresponding to the HVAC system and power wire selection circuitry operative to select which wire connector is electrically coupled to a power node, the method further comprising:

instructing the power wire selection circuitry to electrically couple the power node to one of the HVAC wire connectors depending on the determined HVAC wiring scheme.

7. The method according to claim 6, wherein when the determined HVAC wiring scheme is the multiple circuit system, the method further comprising:

determining which, if any, circuits are changing or about to change from an enabled state to a non-enabled state or from a non-enabled state to an enabled state; and

instructing the power wire selection circuitry to electrically couple the power node to a HVAC wire connector associated with one of the circuits that is in the non-enabled state.

8. The method according to claim 6, wherein when the determined HVAC wiring scheme is the multiple circuit system, the multiple circuit system including first and second switch circuits, the method further comprising:

at a first time period, the first and second switch circuits are in a non-enabled state;

instructing the power wire selection circuitry to electrically couple the power node to the HVAC wire connector associated with the first switch circuit during the first time period;

at a second time period, the first switch circuit switches from the non-enabled state to an enabled phase and that the second switch circuit is in the non-enabled state; and

instructing the power wire selection circuitry to electrically couple the power node to the HVAC wire connector associated with the second switch circuit during the second time period.

9. A thermostat, comprising:

a plurality of HVAC (heating, ventilation, and air conditioning) wire connectors operative to receive a plurality of HVAC wires corresponding to an HVAC system;

control circuitry operative to at least partially control the operation of the HVAC system;

power wire selection circuitry connected to the HVAC wire connectors and to the control circuitry, the power wire selection circuitry operative to select which wire connector is electrically coupled to a power node;

powering circuitry operative to receive power from the power wire selection circuitry via the power wire selection circuitry;

wherein the control circuitry is further operative to;

determine an HVAC wiring scheme based on which wire connectors have received HVAC wires;

cause the power circuitry to operate according to a selected one of a plurality of power schemes based on the determined HVAC wiring scheme; and

instruct the power wire selection circuitry to selectively couple a predetermined one of the wire connectors to the power node based on the determined HVAC wiring scheme and the selected power scheme.

10. The thermostat according to claim 9, wherein when the HVAC wiring scheme is indicative of a single HVAC circuit having a wire connector connected to a HVAC call relay coil and no common wire is connected to any of the wire connectors, the control circuitry instructs the power wire selection circuitry to couple the wire connector associated with the HVAC call relay coil to the power node.

11. The thermostat according to claim 10, wherein the control circuitry further enables the power circuitry to inactively steal power from the HVAC call relay coil when the single HVAC circuit is not experiencing an active HVAC call and to actively steal power from the HVAC call relay coil when the single HVAC circuit is experiencing an active HVAC call.

12. The thermostat according to claim 9, wherein the HVAC wiring scheme is indicative of multiple HVAC circuits each having a wire connector connected to a different HVAC call relay coil and no common wire is connected to any of the wire connectors.

13. The thermostat according to claim 12, wherein the control circuitry is further operative to cause the power circuitry to operate according to an inactive power stealing scheme regardless of whether any one of the multiple HVAC circuits is experiencing an active HVAC call.

14. The thermostat according to claim 13, wherein the control circuitry is further operative to instruct the power wire selection circuitry to selectively couple the power node to the wire connector associated with the HVAC call relay coil of any one of the multiple HVAC circuits that is NOT experiencing an active HVAC call.

15. The thermostat according to claim 13, wherein the multiple HVAC circuits comprise first and second HVAC circuits, the first HVAC circuit comprising a first HVAC call relay coil and the second HVAC circuit comprising a second HVAC call relay coil.

16. The thermostat according to claim 15, wherein,

at a first time period, the power node is connected to the wire connector associated with the first HVAC call relay coil and the first and second HVAC circuits are both NOT experiencing an active HVAC call;

at a second time period after the first time period, the first HVAC circuit switches from NOT experiencing an active HVAC call to experiencing an active HVAC call, and the second HVAC circuit is NOT experiencing an HVAC call; and

in response to the first HVAC circuit switching to an active HVAC, the control circuitry is further operative to instruct the HVAC wire selection circuitry to selectively couple the power node to the wire connector associated with the second HVAC call relay coil.

17. The thermostat according to claim 16, wherein the control circuitry is operative to cause the power circuitry to inactively power steal from the first HVAC call relay coil during the first time period.

18. The thermostat according to claim 16, wherein the control circuitry is operative to cause the power circuitry to inactively power steal from the second HVAC call relay coil during the second time period.

19. The thermostat according to claim 9, wherein when the HVAC wiring scheme is indicative of a common wire connected to one of the wire connectors, the control circuitry is further operative to:

instruct the power wire selection circuitry to couple the power node to the wire connector associated with the common wire; and

enable the power circuitry to draw more power from the wire connector associated with the common wire than the power circuitry can draw when operating according to one of the power stealing schemes.

20. A thermostat, comprising:

a plurality of wiring connectors operative to connect to a plurality of HVAC wires;

insertion sensing circuitry operative to provide insertion sensing signals indicative of which wiring connectors have an HVAC wire connected thereto;

power wire selection circuitry comprising an output node, a control node, and at least two input nodes, each input node is electrically coupled to a different one of at least two wiring connectors, the power wire selection circuitry operative to selectively couple any input node to the output node based on a signal received at the control node;

a microcontroller operative to receive the insertion sensing signals and process HVAC call signals, the HVAC call signals including at least two different types of calls, the microcontroller further operative to;

determine an HVAC wiring scheme based on the received insertion sensing signals;

implement a power scheme based on the determined HVAC wiring scheme;

provide a selection signal to the control node based on the determined HVAC wiring scheme, the HVAC call signal, and the implemented power scheme.

21. The thermostat according to claim 20, wherein when the HVAC wiring scheme is indicative of a single HVAC circuit with no common wire, the implemented power scheme includes in-active power stealing and active power stealing.

22. The thermostat according to claim 20, wherein when the HVAC wiring scheme is indicative of a single HVAC circuit with no common wire, the selection signal causes the power selection circuitry to permanently couple the output node to the input node associated with the wiring connector associated with the relay wire of the single-circuit HVAC connection.

23. The thermostat according to claim 20, wherein when the HVAC wiring scheme is indicative of multiple HVAC circuits with no common wire, the implemented power scheme only uses in-active power stealing.

24. The thermostat according to claim 20, wherein when the HVAC wiring scheme is indicative of multiple HVAC circuits with no common wire, and the HVAC call signal requires use of a first of the HVAC circuits, the selection signal causes the power selection circuitry to couple the output node to the input node associated with the wiring connector associated with a second of the HVAC circuits.