Fig. 1. Structure of temperature control system

Fig. 2. PT1000 three wire connection method

Fig. 3. Three-wire PT1000 temperature measurement module

Fig. 4. Voltage amplifier circuit

Fig. 5. Temperature measurement and acquisition module

Fig. 6. TEC and PTC control circuit

Fig. 7. Extractor fan control circuit

Fig. 8. Variable domain fuzzy PID control structure

Fig. 9. Mathematical model of temperature control system

Fig. 10. Simulation model of variable domain fuzzy PID control

Fig. 11. Comparison of response curves of three controllers

Fig. 12. System test platform

Fig. 13. Test result when PWM duty cycle is set to 50%

Fig. 14. Voltage of A/D conversion module

Fig. 15. Test result at target temperature of 60 ℃

Fig. 16. Test result at target temperature of 40 ℃