METHOD AND APPARATUS FOR COORDINATING THE CONTROL OF HVAC UNITS

• US 20090222139A1
• Filed: 03/03/2009
• Published: 09/03/2009
• Est. Priority Date: 03/03/2008
• Status: Active Grant

• Current Assignee: Vigilent Corporation
• Original Assignee: Federspiel Corp
• Inventors: Federspiel, Clifford C.
• Granted Patent: US 8,224,489 B2
• Time in Patent Office: Days
• US Class Current: 700/278
• 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 11/62 characterised by the type of control or by internal processing, e.g. using fuzzy logic, adaptive control or estimation of values
• CPC Class Codes: G05D 22/02 characterised by the use of electric means
• CPC Class Codes: G05D 23/1931 to control the temperature of one space
• CPC Class Codes: H05K 7/20836 Thermal management, e.g. server temperature control

Abstract

A control strategy for heating, ventilating, and air-conditioning (HVAC) units used to condition the environment in data centers and other commercial buildings such as retail stores with an open-plan design is provided to coordinate the operation of the actuators of the HVAC units. A supervisory controller receives feedback signals from a plurality of environmental sensors and uses a set of references values to determine control signals to the actuators of the HVAC units. A pseudoinverse of a transfer function matrix G may be used to determine the control signals from errors in the feedback signals relative to the reference signals.

Claims

1. A method of controlling an environmental maintenance module using a plurality of sensors, the method comprising:

receiving a first set of environmental measurements, each environmental measurement being from a respective one of the sensors;

determining differences between the environmental measurements and a plurality reference values, each difference being between a respective environmental measurement and a corresponding reference value; and

calculating a change value for an operational parameter of the environmental maintenance module, wherein the change value includes contributions derived from at least two of the differences.

2. The method of claim 1, further comprising:

calculating at least one additional change value for at least one additional operational parameter of the environmental maintenance module.

3. The method of claim 1, further comprising:

determining a new value for the operational parameter from the change value; and

transmitting the new value for the operational parameter to the environmental maintenance module.

4. The method of claim 3, wherein the new value for the operational parameter is determined using a proportional-integral-derivative (PID) object.

5. The method of claim 4, further comprising:

constraining the new value for the operational parameter to be within a specified range; and

resetting the PUD object based on the constrained output.

6. The method of claim 1, wherein the reference values include temperature settings.

7. The method of claim 1, wherein the environmental maintenance modules are HVAC units.

8. The method of claim 1, further comprising:

calculating at least one additional change value for at least one additional environmental maintenance module, wherein calculating the change values of the operational parameters of the environmental maintenance modules includes multiplying the differences by an inverse of a transfer matrix G, wherein the transfer matrix G relates operational parameters to environmental measurements from the sensors.

9. The method of claim 8, wherein the inverse is a pseudoinverse.

10. The method of claim 8, further comprising modifying the transfer matrix G by multiplying a status matrix that relates which sensors or which modules are currently operational.

11. The method of claim 10, wherein the status matrix has zero values along a respective dimension when a corresponding sensor or module is turned off or failed.

12. The method of claim 8, wherein the transfer matrix relates an amount of increase/decrease in an environmental measurement of each sensor created by a change in a respective operational parameter of each environmental maintenance module.

13. The method of claim 12, wherein the transfer matrix has one dimension being a total number of operational parameters of the environmental maintenance modules and the other dimension being the number of sensors.

14. The method of claim 8, wherein the measurements from each sensor are used to calculate the change value of the operational parameters for every environmental maintenance module.

15. The method of claim 8, wherein the inverse of the transfer matrix G is a reduced-order pseudoinverse.

16. The method of claim 15, further comprising determining the reduced-order pseudoinverse, the determining including:

computing a singular value decomposition of G;

identifying a number of significant singular values resulting from the singular value decomposition as being significant

multiplying the transfer matrix G by a matrix V of right singular vectors for the significant singular values to provide a resultant matrix; and

calculating an inverse of the resultant matrix to provide the reduced-order pseudoinverse.

18. The system of claim 1, wherein the one or more processors are further configured to:

calculate at least one additional change value for at least one additional environmental maintenance module, wherein calculating the change values of the operational parameters of the environmental maintenance modules includes multiplying the differences by an inverse of a transfer matrix G, wherein the transfer matrix G relates operational parameters to environmental measurements from the sensors.

19. The system of claim 8, wherein the one or more processors are further configured to:

modify the transfer matrix G by multiplying a status matrix that relates which sensors or which modules are currently operational.

20. The system of claim 8, wherein the inverse of the transfer matrix G is a reduced-order pseudoinverse, and wherein the one or more processors are configured to determine the reduced-order pseudoinverse, the determining including:

computing a singular value decomposition of G;

identifying a number of significant singular values resulting from the singular value decomposition as being significant

multiplying the transfer matrix G by a matrix V of right singular vectors for the significant singular values to provide a resultant matrix; and

calculating an inverse of the resultant matrix to provide the reduced-order pseudoinverse.

17. A system for controlling an environmental maintenance module using a plurality of sensors, the system comprising:

an input interface for receiving a first set of environmental measurements, each environmental measurement being from a respective one of the sensors;

one or more processors configured to;

determine differences between the environmental measurements and a plurality reference values, each difference being between a respective environmental measurement and a corresponding reference value; and

calculate a change value for an operational parameter of the environmental maintenance module, wherein the change value includes contributions derived from at least two of the differences; and

an output interface for sending a new value for the operational parameter to the environmental maintenance module.

21. A method of controlling a plurality of environmental maintenance modules using a plurality of sensors, the method comprising:

receiving a first set of environmental measurements, each environmental measurement being from a respective one of the sensors;

determining differences between the environmental measurements and a plurality reference values, each difference being between a respective environmental measurement and a corresponding reference value; and

calculating a first change value for an operational parameter for a first environmental maintenance module, wherein the first change value includes a first contribution derived from the difference associated with a first sensor;

calculating a second change value for the operational parameter for a second environmental maintenance module, wherein the second change value includes a second contribution derived from the difference associated with the first sensor, wherein the first contribution is different from the second contribution.

22. The method of claim 21, wherein calculating the first and second change values of the operational parameters of the environmental maintenance modules includes multiplying the differences by an inverse of a transfer matrix, wherein the transfer matrix relates operational parameters to environmental measurements from the sensors, and wherein a first transfer matrix element relating the operational parameter for the first environmental maintenance module to the first sensor is different than a second transfer matrix element relating the operational parameter for the second environmental maintenance module to the first sensor.