High Precision Vacuum Temperature Control System Based On Thermoelectric Cooler

Scientific loads operating in space satellites,such as laser interferometers for detecting gravitational waves and electrostatic accelerometers for measuring the earth’s gravity field,are vulnerable to slow and small temperature changes caused by space thermal radiation,so thermal environment simulation tests need to be carried out.At present,the temperature change rate of ground thermal environment simulation equipment is about 0.5 ℃/ min,and the temperature uniformity can only reach within± 2 ℃,which can not meet the slow temperature control requirements of MK on the installation surface of scientific load.Therefore,the research on thermal environment simulation technology and related equipment is of great significance.Firstly,this paper analyzes the ground temperature simulation heating method and equipment,puts forward a high-precision temperature control system using thermoelectric cooler as the core temperature control device,and designs the overall scheme of the temperature control system.The TEC temperature control system is theoretically designed and calculated,the appropriate Tec model and heat dissipation mode are selected,and the temperature uniformity of the design structure is simulated.In the aspect of hardware circuit,the measurement requirements of the system are analyzed and calculated,the temperature sensor and AD converter are selected,and the constant current source circuit for platinum resistance measurement is designed;In view of the problems that the cooling and heating of the thermoelectric cooler needs to switch the current control direction,and the current thermoelectric cooler driving circuit has weak output current capacity,unstable output current and low output energy efficiency,a thermoelectric cooler driving circuit with stable output is designed to realize the flexible switching of heating and cooling;Starting from the functional requirements of the system hardware,the main control circuit,level conversion circuit,communication circuit and storage circuit are designed.In terms of temperature control,thermoelectric cooler is selected as the core temperature control device;Aiming at the integral saturation problem of PID temperature control,the variable speed anti saturation integral is proposed to control the temperature,which effectively solves the temperature control lag of the system;The software design completes the programming of temperature acquisition,upper and lower computer communication,TEC drive control and so on.The upper computer interface of the system is designed with Lab VIEW.In the key performance test of the system,the system temperature measurement is calibrated and calibrated.Finally,it shows that the accuracy of the system temperature measurement is better than ± 0.01 ℃;The results show that the constant temperature control stability of the temperature control system is within ± 0.008 ℃,the lowest uniform temperature rise rate can reach 0.025 ℃/ 1000 s,and the rate control stability is within ± 0.002 ℃/ 1000 s.