Research on high precision temperature control system using linear auto disturbance rejection technique

With the development of photoelectric measurement technology, infrared gas detection technology is widely used in many fields. Temperature has an important influence on the detection of gas concentration and isotopic abundance. The traditional temperature control system using proportional integral differential (PID) control algorithm has the disadvantages of overshoot, slow response time and low precision. Firstly, COMSOL software is used to determine the heating structure by finite element analysis. Secondly, the STM32 single chip microcomputer is used to collect real-time temperature data through 16 bit AD chip LTC1864. Finally, the linear auto disturbance rejection algorithm (LADRC) is used to adjust the PWM wave that achieve the high-precision and real-time dynamic adjustment of the system temperature by controlling the semiconductor cooler (TEC). Under the temperature of 19.8 ℃ condition, an temperature control experiments with a target temperature of 32 ℃ is carried out. The results show that the standard deviation of temperature fluctuation is 0.0357 ℃. Compared with the temperature control system using PID algorithm, it has the advantages of no overshoot, fast response time and high precision.