Thermostat with startup temperature estimation

Patent metadata

Field	Value
Publication number	US-11480356-B2
Application number	US-201816140235-A
Country	US
Kind code	B2
Filing date	Sep 24, 2018
Priority date	Dec 11, 2017
Publication date	Oct 25, 2022
Grant date	Oct 25, 2022

Abstract

A thermostat is disclosed. The thermostat can include one or more temperature sensors configured to measure a plurality of temperature values within a building. The thermostat can include a processing circuit coupled to the one or more temperature sensors. The processing circuit can receive the plurality of measured temperature values from the one or more temperature sensors. The processing circuit can determine, based on a time invariant Non-Linear Least Squares (NLSQ) technique and the plurality of measured temperature values, a compensated temperature value within the building, wherein the compensated temperature value accounts for an unknown temperature state of the thermostat when the thermostat is turned on.

First claim

What is claimed is:

1. A thermostat comprising:
one or more temperature sensors configured to measure a plurality of temperature values within a building; and
a processing circuit, coupled to the one or more temperature sensors, and configured to:
receive the plurality of measured temperature values from the one or more temperature sensors;
determine, based on a time invariant nonlinear estimation technique and the plurality of measured temperature values, a compensated temperature value within the building, wherein the compensated temperature value accounts for an unknown temperature state of the thermostat when the thermostat is turned on, wherein heating, ventilating, or air conditioning equipment is controlled using the compensated temperature value.

2. The thermostat of claim 1 , wherein the processing circuit is configured to determine the compensated temperature value with the nonlinear estimation technique by:
determining a heat rise with the nonlinear estimation technique; and
determining the compensated temperature value based on at least one of the plurality of measured temperature values and the determined heat rise.

3. The thermostat of claim 2 , wherein the processing circuit is configured to determine the compensated temperature value with the nonlinear estimation technique, the plurality of measured temperature values, and a heat rise state space model by:
determining a temperature error with a residual function based on the heat rise state space model and at least one of the plurality of measured temperature values; and
determining the heat rise with the nonlinear estimation technique and the temperature error.

4. The thermostat of claim 3 , wherein determining the heat rise with the nonlinear estimation technique comprises iteratively determining the temperature error with the residual function until the heat rise, determined by the nonlinear estimation technique, converges.

5. The thermostat of claim 3 , wherein determining the heat rise value with the nonlinear estimation technique comprises iteratively determining the temperature error with the residual function for a predetermined number of times.

6. The thermostat of claim 1 , wherein the processing circuit is configured to determine the compensated temperature value within the building with the nonlinear estimation technique, the plurality of temperature values, a heat rise state space model, and an initial state of a state space model,

θ
0

=

[

a
⁢

/

⁢
2

T
Measured

⁡

(
0
)

-

a
⁢

/

⁢
2

T
Measured

⁡

(
0
)

]

,

wherein T Measured is a first of the plurality of measured temperature values and a is a predetermined value.

7. A thermostat comprising:
one or more temperature sensors configured to measure a temperature value within a building; and
a processing circuit, coupled to the one or more temperature sensors, and configured to:
receive the measured temperature value from the one or more temperature sensors; and
determine, based on a heat rise model, a time invariant recursive estimation filter, and the measured temperature value, a compensated temperature value within the building, wherein the compensated temperature value accounts for an unknown temperature state of the thermostat when the thermostat is turned on, wherein heating, ventilating, or air conditioning equipment is controlled using the compensated temperature value.

8. The thermostat of claim 7 , wherein the unknown temperature state of the thermostat reflects a state of the thermostat responsive to the thermostat being below, at, or above a room temperature.

9. The thermostat of claim 7 , wherein the time invariant recursive estimation filter is based on a state covariance matrix, a process noise covariance, a measurement noise covariance, and an initial state, wherein:
the state covariance matrix is initialized to one or more values above one or more first predefined values;
the process noise covariance is initialized to an identify matrix multiplied by a value below a second predefined value;
the measurement noise covariance indicates a variance of the one or more temperature sensors; and
the initial state of the time invariant recursive estimation filter comprise three states, wherein the three states comprise zero, a zone temperature state, and the zone temperature state.

10. The thermostat of claim 9 , wherein the heat rise model is a state space model comprising at least three states, wherein the at least three states comprise:
a heat rise state indicating a heat rise temperature caused by heat generating components of the thermostat;
a measured temperature state indicating the temperature value measured by the one or more temperature sensors; and
the zone temperature state indicating a temperature of a zone, wherein the compensated temperature value within the building is associated with the zone temperature state.

11. The thermostat of claim 10 , wherein the measured temperature state is a sum of the heat rise state and the zone temperature state.

12. The thermostat of claim 10 , wherein the heat rise state is modeled with a first order differential equation with a single pole, wherein the first order differential equation comprises predetermined values for the single pole and a predetermined value for a rise above ambient amplitude value, wherein the first order differential equation models a heat rise within the thermostat.

13. The thermostat of claim 12 , wherein the state space model is defined by:

(

T
HR

Assignees

• Johnson Controls Tech Co
• Johnson Controls Tyco IP Holdings LLP

Inventors

• Zimmerman Nathan M
• Ajax Michael J

Classifications

• F24F11/63 Primary

  Electronic processing · CPC title

• G05D23/1931

  to control the temperature of one space · CPC title

• F24F2110/10

  Temperature · CPC title

• F24F11/88

  Electrical aspects, e.g. circuits · CPC title

• G01K7/427

  Temperature calculation based on spatial modeling, e.g. spatial inter- or extrapolation · CPC title