Method and apparatus for coordinating the control of HVAC units
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.
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 of reference values, each difference being between a respective environmental measurement and a corresponding reference value;
calculating a change value for an operational parameter of the environmental maintenance module, wherein the change value is determined from a sum that includes at least two of the differences, the operational parameter corresponding to an actuator of the environmental measurement module;
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, wherein the new value for the operational parameter changes an operation of the corresponding actuator based on the at least two 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 , wherein the new value for the operational parameter is determined using a proportional-integral-derivative (PID) object.
4. The method of claim 3 , further comprising:
constraining the new value for the operational parameter to be within a specified range; and
resetting the PID object based on the constrained output.
5. The method of claim 1 , wherein the reference values include temperature settings.
6. The method of claim 1 , wherein the environmental maintenance module is a HVAC unit.
7. 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.
8. The method of claim 7 , wherein the inverse is a pseudoinverse.
9. 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 of reference values, each difference being between a respective environmental measurement and a corresponding reference value;
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;
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; and
modifying the transfer matrix G by multiplying a status matrix that relates which sensors or which modules are currently operational.
10. The method of claim 9 , wherein the status matrix has zero values along a respective dimension when a corresponding sensor or module is turned off or failed.
11. The method of claim 7 , 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.
12. The method of claim 11 , 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.
13. The method of claim 7 , wherein the measurements from each sensor are used to calculate the change value of the operational parameters for every environmental maintenance module.
14. The method of claim 7 , wherein the inverse of the transfer matrix G is a reduced-order pseudoinverse.
15. 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 of reference values, each difference being between a respective environmental measurement and a corresponding reference value;
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;
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; wherein the inverse of the transfer matrix G is a reduced-order pseudoinverse; and
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.
16. 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 of reference values, each difference being between a respective environmental measurement and a corresponding reference value;
calculate a change value for an operational parameter of the environmental maintenance module, wherein the change value is determined from a sum that includes at least two of the differences, the operational parameter corresponding to an actuator of the environmental measurement module;
determine a new value for the operational parameter from the change value; and
transmit the new value for the operational parameter to the environmental maintenance module, wherein the new value for the operational parameter changes an operation of the corresponding actuator based on the at least two differences; and
an output interface for sending a new value for the operational parameter to the environmental maintenance module.
17. The system of claim 16 , 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.
18. 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 of reference values, each difference being between a respective environmental measurement and a corresponding reference value;
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;
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; and
modify the transfer matrix G by multiplying a status matrix that relates which sensors or which modules are currently operational; and
an output interface for sending a new value for the operational parameter to the environmental maintenance module.
19. 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 of reference values, each difference being between a respective environmental measurement and a corresponding reference value;
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
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; and
an output interface for sending a new value for the operational parameter to the environmental maintenance module, 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.
20. 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 of reference values, each difference being between a respective environmental measurement and a corresponding reference value;
calculating a first change value for a first operational parameter for a first environmental maintenance module, wherein the first change value is determined from a first contribution that includes the difference associated with a first sensor, the first operational parameter corresponding to a first actuator of the first environmental measurement module;
determining a first new value for the first operational parameter from the first change value;
transmitting the first new value for the first operational parameter to the first environmental maintenance module, wherein the new value for the first operational parameter changes an operation of the first actuator;
calculating a second change value for a second operational parameter for a second environmental maintenance module, wherein the second change value is determined from a second contribution that includes the difference associated with the first sensor, the second operational parameter corresponding to a second actuator of the second environmental measurement module, wherein the first contribution is different from the second contribution;
determining a second new value for the second operational parameter from the second change value; and
transmitting the second new value for the second operational parameter to the second environmental maintenance module, wherein the second new value for the second operational parameter changes an operation of the second actuator.
21. The method of claim 20 , 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.