The Design of Liquid Helium Temperature Zone Temperature Control System Based on G-M Refrigerator

The different low temperature electrical characteristics of insulating materials, which plays an important role in superconducting power equipment, has attracted extensive attention. The cryogenic control system is applied to the independent development of superconducting electrical characteristics of insulating materials testing device. And it is designed on the basis of LabVIEW, for the test of the electrical characteristics of the insulation materials in special environment such as cryogenic temperature and vacuum. The system which uses DC source as a heat source and G-M refrigerator as a cold source, uses PID algorithm to control the heat source with the cold source so as to achieve closed-loop control. The system can make the temperature of sample from room temperature down to 6.0K within three hours and control the temperature of sample in the range of 6.0K-300.0K. The system enables temperature error not more than ± 0.5K for a long time and provides a reliable low-temperature environment which is used for study of the electrical characteristics of the insulation materials in different cryogenic temperature and vacuum environment.