System and method to position variable diffuser vanes in a compressor device

Abstract

Embodiments of a system and method can modify the position of diffuser vanes to improve performance of a compressor device, e.g., a centrifugal compressor. These embodiments include a feedback loop to manage the position of the diffuser vanes relative to one or more operating characteristics of an actuator that imparts movement to the diffuser vanes. In one embodiment, the system and method measure the operating characteristic for the actuator with the diffuser vanes at a first position and a second position. The system can compare values for the operating characteristics, wherein changes in the operating characteristic can identify other positions for the diffuser vanes to reduce input power the actuator consumes to move and/or maintain the position of the diffuser vanes. This feature can correlate with optimal performance of the compressor device and with peak compressor efficiency within the entire operating envelope of the compressor device.

What is claimed is: 
     
         1 . A system, comprising:
 a compressor device comprising an impeller, a diffuser vane in flow connection with the impeller, and an actuator coupled with the diffuser vane; and   a controller coupled to the compressor device, the controller comprising a processor having access to executable instructions stored on memory and configured to be executed by the processor, the executable instructions comprising instructions for:
 receiving a first input comprising data for a first value of an operating characteristic for the actuator with the diffuser vane in a first position; 
 receiving a second input comprising data for a second value of the operating characteristic for the actuator with the diffuser vane in a second position; 
 comparing the first value and the second value; 
 selecting an increment by which to move the diffuser vane from the second position, the increment defining the relative position of the second value with respect to the first value; and 
 generating an output comprising data to instruct the actuator to move the diffuser vane from the second position by the increment. 
   
     
     
         2 . The system of  claim 1 , wherein the operating characteristic identifies input power to the actuator. 
     
     
         3 . The system of  claim 1 , wherein the operating characteristic correlates with flow characteristics about the diffuser vane. 
     
     
         4 . The system of  claim 1 , wherein the actuator comprises a linear actuator. 
     
     
         5 . The system of  claim 4 , wherein the linear actuator is configured to operate in response to an electrical input. 
     
     
         6 . The system of  claim 4 , wherein the linear actuator is configured to operate in response to a pneumatic input. 
     
     
         7 . The system of  claim 1 , wherein the executable instruction comprise instructions for determining an inlet flow value upstream of the impeller and setting the first position to correspond with the inlet flow value. 
     
     
         8 . The system of  claim 7 , further comprising a flow meter disposed upstream of the impeller, the flow meter providing a third input that comprises data that reflects the inlet flow value, wherein the executable instruction comprise instructions for receiving the third input and instructing the actuator to move the diffuser vanes to the first position. 
     
     
         9 . The system of  claim 1 , wherein the increment changes the position of the diffuser vane in a first direction if the second value is larger than the first value, wherein the increment changes the position of the diffuser vane in a second direction if the second value is smaller than the first value, and wherein the first direction is different from the second direction. 
     
     
         10 . The system of  claim 1 , wherein the executable instructions comprise instructions for comparing the second value to a threshold criteria, wherein the threshold criteria defines a maximum value for the operating parameter and a minimum value for the operating parameter, and wherein the increment changes the position of the diffuser vane if the second value is equal to or greater than the maximum value and equal to or less than the minimum value. 
     
     
         11 . The system of  claim 1 , wherein the diffuser vane has a leading edge and a trailing edge, and wherein the diffuser vane rotates about an axis proximate the leading edge. 
     
     
         12 . The system of  claim 1 , wherein the increment defines an angular offset of the diffuser vane from the second position. 
     
     
         13 . A compressor device, comprising:
 a drive unit;   an impeller coupled to the drive unit;   a diffuser assembly in flow connection with the impeller, the diffuser assembly comprising a diffuser vane   an actuator coupled to the diffuser vane and configured to move the diffuser vane; and   a controller coupled with the actuator, the controller comprising a processor with access to executable instructions configured to be executed by the processor and stored on memory, the executable instructions comprising instructions for:
 receiving a first input with data that relates to a first value for an operating characteristic for the actuator with the diffuser vane in a first position; 
 receiving a second input with data that relates to a second value for the operating characteristic for actuator with the diffuser vane in a second position; 
 comparing the first value and the second value; 
 selecting an increment by which to move the diffuser vane from the second position, the increment defining the relative position of the second value with respect to the first value; and 
 generating an output comprising data to instruct the actuator to move the diffuser vane from the second position by the increment. 
   
     
     
         14 . The compressor device of  claim 13 , further comprising a parameter sensor coupled with the controller, wherein the parameter sensor is in position to measure flow of a working fluid. 
     
     
         15 . The compressor device of  claim 14 , wherein the parameter sensor measures input power to drive the actuator. 
     
     
         16 . The compressor device of  claim 15 , wherein the actuator comprises a pneumatic cylinder. 
     
     
         17 . The compressor device of  claim 15 , wherein the actuator comprises a motor to generate movement of the diffuser vane from the second position. 
     
     
         18 . The compressor device of  claim 13 , wherein the diffuser vane leading edge, a trailing edge, and a rotation axis proximate the leading edge, and wherein the trailing edge rotates about the leading edge when moving from the first position and the second position. 
     
     
         19 . A computer program product for improving efficiency of a compressor device, the computer program product comprising a computer readable storage medium having executable instructions embodied therein, wherein the executable instructions comprise one or more executable instructions for:
 receiving a first input with data that relates to a first value for an operating characteristic for an actuator coupled with a diffuser vane in a first position;   receiving a second input with data that relates to a second value for the operating characteristic for the actuator with the diffuser vane in a second position;   comparing the first value and the second value;   selecting an increment by which to move the diffuser vane from the second position, the increment defining the relative position of the second value with respect to the first value; and   generating an output comprising data to instruct the actuator to move the diffuser vane from the second position by the increment.   
     
     
         20 . The computer program product of  claim 19 , wherein the executable instructions comprise instructions for comparing the second value to a threshold criteria, wherein the threshold criteria defines a maximum value for the operating parameter and a minimum value for the operating parameter, and wherein the increment changes the position of the diffuser vane if the second value is equal to or greater than the maximum value and equal to or less than the minimum value.