INVESTIGATIONS ON THE AUTOMATIC TEMPERATURE CONTROL ELECTRONICS OF THE SINGLE STAGE SPACE STIRLING-TYPE PULSE TUBE CRYOCOOLER

摘要

In this paper, the automatic temperature control electronics of single stage space Stirling-type pulse tube cryocooler (SPTC) has been investigated theoretically and experimentally. Pulse width modulation technique is implemented to provide sinusoidal drive to the linear compressor under DC power supply. Digital expert PID control algorithm is applied to provide the temperature control. Mathematical model of the SPTC has been proposed and relevant simulations have been done. The design considerations of the hardware and control software of the electronics are described in detail. The actual control electronics has been worked out and then tested on a typical coaxial SPTC developed in the authors’ laboratory. Experiment shows that the developed automatic temperature control electronics can generate sinusoidal signal under the given DC power supply with the converting efficiency of 95%. And it can also provide the temperature control for the SPTC at 80 K with stability of better than ±0.2 K in 2 hours. With heat load disturbance, the cold temperature stability is better than ±0.3 K.