The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 16, 1996
Filed:
Aug. 22, 1994
Yeong-Wei A Wu, Rancho Palos Verdes, CA (US);
Michael H Kieffer, Redondo Beach, CA (US);
Hughes Electronics, Los Angeles, CA (US);
Abstract
A temperature control apparatus and method for active control of a Stirling-cycle cryocooler cold finger tip temperature, by adjusting the cryocooler compressor piston stroke amplitude. In a control loop of the Stirling cryocooler, having a compressor in which the pistons are reciprocated by linear motors at fundamental frequency and the length of a stroke of the piston is varied as a direct function of cryocooler temperature, temperature is sensed at the cryocooler cold finger tip and the temperature signal is compared with a set temperature signal to produce a temperature error signal. This signal is input in a PID control law module which uses proportional, derivative, and integrated temperature error information to generate the required compressor piston stroke amplitude change for achieving the precision temperature control. The resulting signal is further processed in a distribution law module that distributes the desired piston stoke amplitude change to each compressor motor so that the force balance at the fundamental frequency is maintained.