Central plant control system with control region detection based on control envelope ray-casting
Disclosed herein are related to a system, a method, and a non-transitory computer readable medium for controlling a central plant. In one aspect, the system obtains a control envelope for a device controlled by the controller. The control envelope comprises boundaries of a plurality of control regions in a multidimensional operating space for the device. Each control region is enclosed by a corresponding boundary. The system counts a number of times that a ray of the device crosses the boundary of a control region. The system determines whether an operating point of the device is within the control region based on the counted number. The system operates the device according to a predetermined control technique corresponding to the control region, in response to determining that the operating point of the device is within the control region.
1. A controller, the controller comprising:
a processing circuit comprising a processor and memory storing instructions executed by the processor, the processing circuit configured to:
obtain a control envelope for a device controlled by the controller, the control envelope comprising boundaries of a plurality of control regions in a multidimensional operating space for the device, each control region enclosed by a corresponding boundary;
count a number of times that a ray crosses the boundary of a control region;
determine whether an operating point of the device is within the control region based on the counted number; and
operate the device according to a predetermined control technique corresponding to the control region, in response to determining that the operating point of the device is within the control region.
2. The controller of claim 1 , wherein the processing circuit is further configured to:
determine that the operating point of the device is within the control region, in response to the counted number being an even number.
3. The controller of claim 1 , wherein the processing circuit is further configured to:
determine that the operating point is within another control region, in response to the counted number being an odd number.
4. The controller of claim 1 , wherein two or more control regions overlap with each other.
5. The controller of claim 1 ,
wherein the device is a compressor,
wherein a first control region of the plurality of control regions is associated with a target operating state of the device, the device to operate at a speed within a predetermined range in the target operating state,
wherein a second control region of the plurality of control regions is associated with a speed-up state of the device, the device to operate at a speed above the predetermined range in the speed-up state, and
wherein a third control region of the plurality of control regions is associated with a slow-down state of the device, the device to operate at a speed below the predetermined range in the slow-down state.
6. The controller of claim 1 , wherein the multidimensional operating space of the device includes a saturated discharge temperature and a saturated suction temperature of the device.
7. The controller of claim 1 , wherein the processing circuit is further configured to:
increase an alarm counter in response to determining that the operating point is within the control region associated with a shut-down state, the device to be disabled in the shut-down state for a shut-down time period.
8. The controller of claim 7 , wherein the processing circuit is further configured to:
lockout the device in response to the alarm counter exceeding a predetermined threshold; and
generate a user interface allowing a user operating the controller to unlock the device.
9. The controller of claim 8 , wherein the processing circuit is further configured to:
reset the alarm counter in response to the alarm counter not exceeding the predetermined threshold within a predetermined time period.
10. The controller of claim 1 , wherein the processing circuit is configured to:
detect a change of the operating point of the device to a deadband region; and
operate the device according to the predetermined control technique corresponding to the control region, until the operating point of the device changes to another control region.
11. A method of operating a device, the method comprising:
obtaining a control envelope for the device, the control envelope comprising boundaries of a plurality of control regions in a multidimensional operating space for the device, each control region enclosed by a corresponding boundary;
counting a number of times that a ray crosses the boundary of a control region;
determining whether an operating point of the device is within the control region based on the counted number; and
operating the device according to a predetermined control technique corresponding to the control region, in response to determining that the operating point of the device is within the control region.
12. The method of claim 11 , further comprising:
determining that the operating point of the device is within the control region, in response to the counted number being an even number.
13. The method of claim 11 , further comprising:
determining that the operating point is within another control region, in response to the counted number being an odd number.
14. The method of claim 11 , wherein two or more control regions overlap with each other.
15. The method of claim 11 ,
wherein the device is a compressor,
wherein a first control region of the plurality of control regions is associated with a target operating state of the device, the device to operate at a speed within a predetermined range in the target operating state,
wherein a second control region of the plurality of control regions is associated with a speed-up state of the device, the device to operate at a speed above the predetermined range in the speed-up state, and
wherein a third control region of the plurality of control regions is associated with a slow-down state of the device, the device to operate at a speed below the predetermined range in the slow-down state.
16. The method of claim 11 , further comprising:
increasing an alarm counter in response to determining that the operating point is within the control region associated with a shut-down state, the device to be disabled in the shut-down state for a shut-down time period.
17. The method of claim 16 , further comprising:
locking out the device in response to the alarm counter exceeding a predetermined threshold; and
generating a user interface allowing a user operating the device to unlock the device.
18. The method of claim 17 , further comprising:
resetting the alarm counter in response to the alarm counter not exceeding the predetermined threshold within a predetermined time period.
19. The method of claim 11 , further comprising:
detecting a change of the operating point of the device to a deadband region; and
operating the device according to the predetermined control technique corresponding to the control region, until the operating point of the device changes to another control region.
20. A controller for an energy plant, the controller comprising:
a processing circuit comprising a processor and memory storing instructions executed by the processor, the processing circuit configured to:
obtain a control envelope for a heating, ventilation and air conditioning (HVAC) device controlled by the controller, the control envelope comprising boundaries of a plurality of control regions in a multidimensional operating space for the HVAC device, each control region enclosed by a corresponding boundary;
count a number of times that a ray of the HVAC device crosses the boundary of a control region;
determine whether an operating point of the HVAC device is within the control region based on the counted number; and
operate the HVAC device according to a predetermined control technique corresponding to the control region, in response to determining that the operating point of the HVAC device is within the control region.