Annular cryocooler compressor systems and methods

Abstract

Techniques are disclosed for systems and methods to reduce the overall physical size of and mechanical vibrations within a cryocooler/refrigeration system configured to provide cryogenic and/or general cooling of a device or sensor system. A refrigeration system includes an annular linear compressor configured to generate a compression wave of working gas for the system. The annular linear compressor includes an annular cylinder head with a pressure plate and a neck protruding from one side of the annular cylinder head, a compressor housing configured to mate with the pressure plate and the neck of the annular cylinder head and form a sealed cavity therebetween, and an annular cylinder assembly disposed within the sealed cavity and about the neck of the annular cylinder head. The annular cylinder assembly includes an annular piston assembly disposed within an annular cylinder of the annular cylinder assembly.

What is claimed is: 
     
         1 . A refrigeration system comprising:
 an annular linear compressor configured to generate a compression wave of working gas for the refrigeration system, wherein the annular linear compressor comprises:
 an annular cylinder head comprising a pressure plate and a neck protruding from one side of the annular cylinder head; 
 a compressor housing configured to mate with the pressure plate and the neck of the annular cylinder head and form a sealed cavity therebetween; and 
 an annular cylinder assembly disposed within the sealed cavity and about the neck of the annular cylinder head, wherein the annular cylinder assembly comprises an annular piston assembly disposed within an annular cylinder of the annular cylinder assembly. 
   
     
     
         2 . The refrigeration system of  claim 1 , wherein:
 the annular cylinder assembly comprises inductive windings disposed about an exterior of the annular cylinder and configured to couple inductively with the annular piston assembly.   
     
     
         3 . The refrigeration system of  claim 2 , wherein the annular cylinder assembly comprises:
 an outer yoke disposed at least partially about the inductive windings and between the inductive windings and the annular cylinder; and   an inner yoke disposed between the annular cylinder and the neck of the annular cylinder head;   wherein the inner and outer yokes are configured to help shape magnetic flux generated by the inductive windings and/or motion of the annular piston assembly and inductively couple the inductive windings to the annular piston assembly.   
     
     
         4 . The refrigeration system of  claim 1 , wherein the annular piston assembly comprises:
 an inner split piston head configured to form a first moving seal with an inner annular cylinder surface of the annular cylinder;   an outer split piston head configured to form a second moving seal with an outer annular cylinder surface of the annular cylinder; and   a piston magnet ring disposed in a piston cavity formed by the inner and outer split piston heads and configured to couple inductively with inductive windings of the annular cylinder assembly.   
     
     
         5 . The refrigeration system of  claim 4 , wherein:
 the piston magnet ring comprises a plurality of arcuate magnet segments arranged in a partial or full magnet ring within the annular piston assembly.   
     
     
         6 . The refrigeration system of  claim 1 , wherein:
 the annular cylinder assembly comprises a cylinder magnet ring disposed about an exterior of the annular cylinder and configured to couple inductively with the annular piston assembly, wherein the annular piston assembly comprises a piston inductive windings disposed substantially within a piston cavity formed by inner and outer split piston heads of the annular piston assembly.   
     
     
         7 . The refrigeration system of  claim 1 , wherein:
 the annular linear compressor comprises a gas transfer plate coupled to the pressure plate of the annular cylinder head and configured to mechanically couple to an expander of the refrigeration system and form at least part of a gas transfer line between the annular cylinder head and the expander.   
     
     
         8 . The refrigeration system of  claim 1 , further comprising a cryocooler controller, the cryocooler controller comprising:
 a motor driver controller configured to receive operational parameters corresponding to operation of a cryocooler of the refrigeration system controlled by the cryocooler controller and generate motor driver control signals based, at least in part, on the received operational parameters, wherein the cryocooler comprises the annular linear compressor of the refrigeration system; and   a motor driver configured to receive the motor driver control signals from the motor driver controller and generate drive signals based, at least in part, on the motor driver control signals, to drive the annular linear compressor of the cryocooler.   
     
     
         9 . The refrigeration system of  claim 8 , further comprising:
 a feedback interface configured to receive one or more sensor signals and generate feedback data corresponding to operation of the cryocooler controlled by the cryocooler controller, wherein the motor driver controller is configured to receive the feedback data from the feedback interface and generate the motor driver control signals based, at least in part, on the feedback data and the operational parameters.   
     
     
         10 . The refrigeration system of  claim 9 , wherein:
 the one or more sensor signals comprise a measured temperature of a cold finger of the cryocooler and/or an electronic device thermally coupled to the cryocooler;   the motor driver controller is configured to determine a feedback error based, at least in part, on a set point corresponding to a desired temperature for the cold finger of the cryocooler and/or the electronic device and feedback data corresponding to the measured temperature of the cold finger of the cryocooler and/or the electronic device; and   the motor driver controller is configured to generate the motor driver control signals based, at least in part, on the determined feedback error.   
     
     
         11 . The refrigeration system of  claim 8 , further comprising:
 the cryocooler controlled by the cryocooler controller, wherein the cryocooler comprises an expander disposed within an annular gap of the annular linear compressor.   
     
     
         12 . The refrigeration system of  claim 8 , wherein:
 the annular linear compressor of the cryocooler controlled by the cryocooler controller comprises inductive windings disposed about an exterior of the annular cylinder and configured to be driven by the drive signals generated by the motor driver of the cryocooler controller.   
     
     
         13 . The refrigeration system of  claim 8 , further comprising:
 an electronic device thermally coupled to and at least partially cooled by the cryocooler controlled by the cryocooler controller, wherein the electronic device comprises at least a part of a sensor system or an infrared camera.   
     
     
         14 . A method comprising:
 receiving operational parameters corresponding to operation of a cryocooler controlled by a cryocooler controller;   generating motor driver control signals based, at least in part, on the received operational parameters; and   generating, by a motor driver of the cryocooler controller, drive signals based, at least in part, on the motor driver control signals, to drive an annular linear compressor of the cryocooler, wherein the annular linear compressor comprises:
 an annular cylinder head comprising a pressure plate and a neck protruding from one side of the annular cylinder head; 
 a compressor housing configured to mate with the pressure plate and the neck of the annular cylinder head and form a sealed cavity therebetween; and 
 an annular cylinder assembly disposed within the sealed cavity and about the neck of the annular cylinder head, wherein the annular cylinder assembly comprises an annular piston assembly disposed within an annular cylinder of the annular cylinder assembly. 
   
     
     
         15 . The method of  claim 14 , wherein:
 the annular cylinder assembly comprises inductive windings disposed about an exterior of the annular cylinder and configured to couple inductively with the annular piston assembly, and wherein the annular cylinder assembly comprises:   an outer yoke disposed at least partially about the inductive windings and between the inductive windings and the annular cylinder; and   an inner yoke disposed between the annular cylinder and the neck of the annular cylinder head;   wherein the inner and outer yokes are configured to help shape magnetic flux generated by the inductive windings and inductively couple the inductive windings to the annular piston assembly.   
     
     
         16 . The method of  claim 14 , wherein the annular piston assembly comprises:
 an inner split piston head configured to form a first moving seal with an inner annular cylinder surface of the annular cylinder;   an outer split piston head configured to form a second moving seal with an outer annular cylinder surface of the annular cylinder; and   a piston magnet ring disposed in a piston cavity formed by the inner and outer split piston heads and configured to couple inductively with inductive windings of the annular cylinder assembly.   
     
     
         17 . The method of  claim 14 , wherein:
 the annular cylinder assembly comprises a cylinder magnet ring disposed about an exterior of the annular cylinder and configured to couple inductively with the annular piston assembly, wherein the annular piston assembly comprises a piston inductive windings disposed substantially within a piston cavity formed by inner and outer split piston heads of the annular piston assembly.   
     
     
         18 . The method of  claim 14 , wherein:
 the annular linear compressor comprises a gas transfer plate coupled to the pressure plate of the annular cylinder head and configured to mechanically couple to an expander of the refrigeration system and form at least part of a gas transfer line between the annular cylinder head and the expander.   
     
     
         19 . The method of  claim 14 , further comprising:
 receiving one or more sensor signals corresponding to operation of the cryocooler controlled by the cryocooler controller;   generating feedback data corresponding to the one or more sensor signals;   generating the motor driver control signals based, at least in part, on the feedback data and the operational parameters and   wherein the one or more sensor signals comprises a measured temperature of a cold finger of the cryocooler and/or an electronic device thermally coupled to the cryocooler, the method further comprising:   determining a feedback error based, at least in part, on a set point corresponding to a desired temperature for the cold finger of the cryocooler and/or the electronic device and feedback data corresponding to the measured temperature of the cold finger of the cryocooler and/or the electronic device; and   generating the motor driver control signals based, at least in part, on the determined feedback error.   
     
     
         20 . The method of  claim 14 , further comprising cooling an electronic device thermally coupled to the cryocooler controlled by the cryocooler controller, wherein:
 the annular linear compressor of the cryocooler controlled by the cryocooler controller comprises a linear motor driven by the drive signals generated by the motor driver of the cryocooler controller; and   the electronic device comprises at least a part of a sensor system or an infrared camera.