Rotary machine including active magnetic bearing

Abstract

A method of operating a rotary machine. The method includes rotating a rotor; receiving current at at least one electromagnetic bearing supporting the rotor; detecting an operating characteristic of the rotary machine; determining, using a controller, an operating state of the rotary machine based on the detected operating characteristic; retrieving operating modes stored in a memory of the controller, the operating modes including a normal operating mode and a fault tolerant operating mode; switching between the normal operating mode and the fault tolerant operating mode, using the controller, based on the determined operating state of the rotary machine; regulating, using the controller, at least one of a magnetic force and a position of the at least one electromagnetic bearing; and regulating, using the controller, at least one of a position and an opening of at least one fluid flow control device.

What is claimed is: 
     
         1 . A method of operating a rotary machine, said method comprising:
 rotating a rotor;   receiving current at at least one electromagnetic bearing supporting the rotor;   detecting an operating characteristic of the rotary machine;   determining, using a controller, an operating state of the rotary machine based on the detected operating characteristic;   retrieving operating modes stored in a memory of the controller, the operating modes including a normal operating mode and a fault tolerant operating mode;   switching between the normal operating mode and the fault tolerant operating mode, using the controller, based on the determined operating state of the rotary machine;   regulating, using the controller, at least one of a magnetic force and a position of the at least one electromagnetic bearing; and   regulating, using the controller, at least one of a position and an opening of at least one fluid flow control device.   
     
     
         2 . The method in accordance with  claim 1 , wherein the rotary machine is a compressor, and wherein determining, using the controller, the operating state of the rotary machine based on the operating characteristic comprises determining if the operating characteristic of the rotary machine is indicative of a near choke condition or an increased volume flow condition of the rotary machine. 
     
     
         3 . The method in accordance with  claim 1 , wherein regulating, using the controller, operation of the at least one electromagnetic bearing comprises regulating the at least one electromagnetic bearing in the normal operating mode based on a first set of parameters, and regulating the at least one electromagnetic bearing in the fault tolerant operating mode based on a second set of parameters, the second set of parameters including at least one parameter that is not included in the first set of parameters. 
     
     
         4 . The method in accordance with  claim 1 , wherein regulating, using the controller, operation of at least one component of the rotary machine other than the at least one electromagnetic bearing comprises regulating, using the controller, the at least one fluid flow control device of the rotary machine. 
     
     
         5 . The method in accordance with  claim 1 , wherein regulating, using the controller, operation of the at least one electromagnetic bearing comprises regulating, using the controller, at least one of a thrust actuator and a radial actuator. 
     
     
         6 . The method in accordance with  claim 1 , further comprising determining if the operating state of the rotary machine is within fault tolerant control parameters based on operating maps stored in the memory.