Adaptive response time closed loop control algorithm

• US 20070276545A1
• Filed: 04/28/2006
• Published: 11/29/2007
• Est. Priority Date: 04/28/2006
• Status: Active Grant

• Current Assignee: Hitachi Metals (Thailand) Ltd.
• Original Assignee: Advanced Energy Industries Incorporated
• Inventors: Smirnov, Alexei
• Granted Patent: US 7,603,186 B2
• Time in Patent Office: Days
• US Class Current: 700/282
• CPC Class Codes: G05B 13/024 in which a parameter or coefficient is automatically adjusted to optimise the performance
• CPC Class Codes: G05D 7/0635 by action on throttling means G05D7/0688, G05D7/0694 take precedence
• CPC Class Codes: Y10T 137/0324 With control of flow by a condition or characteristic of a fluid
• CPC Class Codes: Y10T 137/7759 Responsive to change in rate of fluid flow

Abstract

A system and method for controlling a flow of a fluid using an adaptive closed-loop-control algorithm is described. One embodiment includes a method for receiving a set point indicator and/or a sensor indicator generated by a sensor. A response time of a closed-loop-control algorithm is modified when at least one threshold value is satisfied based on the sensor indicator and/or the set point indicator. The closed-loop-control algorithm, which is implemented by a flow controller, is stabilized in response to the modifying of the response time of the closed-loop-control algorithm by adjusting at least one parameter associated with the closed-loop-control algorithm.

Claims

1. A method, comprising:

receiving at least one of a set point indicator or a sensor indicator generated by a sensor;

modifying the response time of a closed-loop-control algorithm when at least one threshold condition is satisfied based on the at least one of the sensor indicator or the set point indicator, the closed-loop-control algorithm being associated with a flow controller; and

stabilizing the closed-loop-control algorithm in response to the modifying the response time of the closed-loop-control algorithm by adjusting at least one parameter associated with the closed-loop-control algorithm.

2. The method of claim 1, further comprising detecting a change in the at least one of the sensor indicator or the set point indicator, the at least one threshold condition is satisfied by the change.

3. The method of claim 1, further comprising detecting a rate of change in the at least one of the sensor indicator or the set point indicator, the at least one threshold condition is satisfied by the rate of change.

4. The method of claim 1, wherein:

the sensor indicator is a flow sensor indicator that indicates a flow rate of a fluid,

the set point indicator indicates a fluid flow set point,

the at least one threshold condition is based on a flow rate error value, the flow rate error value is a difference between the fluid flow set point and the flow rate of the fluid.

5. The method of claim 1, wherein the modifying includes at least one of accelerating or decelerating.

6. The method of claim 1, wherein the modifying includes modifying in response to a change in a fluid flow rate through the flow controller and according to a mathematical equation.

7. The method of claim 1, further comprising compensating for at least one non-linear characteristic associated with the flow controller by modifying an adaptive-gain based on the at least one of the sensor indicator or the set point indicator, the adaptive-gain being associated with the closed-loop-control algorithm, the modifying the adaptive-gain includes modifying in response to a change in a fluid flow rate through the flow controller and according to a mathematical equation.

8. The method of claim 1, wherein the modifying includes modifying at least one filter associated with the closed-loop-control algorithm.

9. The method of claim 1, wherein the modifying includes modifying a response time of a feedback filter by adjusting a time constant associated with the feedback filter, the feedback filter being associated with the closed-loop-control algorithm.

10. The method of claim 1, wherein the at least one parameter is a tuning parameter associated with the closed-loop-control algorithm.

11. The method of claim 1, wherein the stabilizing includes stabilizing based on the at least one of the sensor indicator or the set point indicator.

12. The method of claim 1, wherein the closed-loop-control algorithm is based on at least one of proportional control, integral control, or derivative control.

13. The method of claim 1, wherein the sensor is at least one of a flow sensor, a timer, a pressure sensor or a temperature sensor.

14. A method, comprising:

receiving at least one of a set point indicator or a sensor indicator generated by a sensor;

modifying a feedback filter from a first mode to a second mode based on the at least one of the sensor indicator or the set point indicator, the feedback filter being associated with a closed-loop-control algorithm, the closed-loop-control algorithm being associated with a flow controller; and

changing a tuning parameter associated with the closed-loop-control algorithm based on the modifying the feedback filter, the tuning parameter being changed to stabilize the closed-loop-control algorithm when the feedback filter is modified.

15. The method of claim 14, further comprising modifying an adaptive-gain based on the at least one of the sensor indicator or the set point indicator, the adaptive-gain being used in the closed-loop-control algorithm to compensate for at least one non-linear characteristic associated with the flow controller.

16. The method of claim 14, further comprising modifying an adaptive-gain based on the at least one of the sensor indicator or the set point indicator, the adaptive-gain is used in the closed-loop-control algorithm to compensate for at least one non-linear characteristic associated with the flow controller, the modifying the adaptive-gain includes modifying in response to a change in a fluid flow rate through the flow controller and according to a mathematical equation.

17. The method of claim 14, wherein the modifying the feedback filter includes modifying a response time associated with the feedback filter by adjusting a time constant associated with the feedback filter.

18. The method of claim 14, wherein the closed-loop-control algorithm is based on at least one of proportional control, integral control, or derivative control.

19. The method of claim 14, wherein the tuning parameter is associated with an integral control portion of the closed-loop-control algorithm.

20. The method of claim 14, wherein the sensor is at least one of a flow sensor, a timer, a pressure sensor or a temperature sensor.

21. The method of claim 14, wherein the modifying the feedback filter includes modifying in response to a change in a fluid flow rate through the flow controller and according to a mathematical equation.

22. The method of claim 14, wherein a response time of the closed-loop-control algorithm is different when the feedback filter is in the first mode than when the feedback filter is in the second mode.

23. The method of claim 14, wherein the modifying the feedback filter includes modifying with reference to at least one threshold value associated with the at least one of the sensor indicator or the set point indicator.

24. The method of claim 14, wherein the modifying the feedback filter includes gradually modifying the feedback filter in response to a change in a fluid flow rate through the flow controller and according to a mathematical equation.

25. An apparatus, comprising:

a processor configured to modify a response time of a closed-loop-control algorithm when at least one threshold value is satisfied based on at least one of a sensor indicator generated by a sensor or a set point indicator, the processor modifies the response time of the closed-loop-control algorithm by modifying a feedback filter associated with the closed-loop-control algorithm and a tuning parameter associated with the closed-loop-control algorithm; and

a memory configured to store a parameter associated with at least one of the feedback filter and the tuning parameter, the processor accesses the parameter from the memory.

26. The apparatus of claim 25, further comprising a valve configured to open and close in response to a control indicator, the control indicator being generated by the processor based on the closed-loop-control algorithm.

27. The apparatus of claim 25, wherein the sensor is at least one of a flow sensor, a timer, a pressure transducer or a temperature sensor.

28. The apparatus of claim 25, wherein the processor is configured to modify an adaptive gain associated with the closed-loop-control-algorithm based on the at least any one of the sensor indicator or the set point indicator, the adaptive-gain is used in the closed-loop-control algorithm to compensate for at least one non-linear characteristic associated with the valve.

29. The apparatus of claim 25, further comprising a memory that is configured to store the at least one threshold value, the processor is configured to access the at least one threshold value from the memory.