Design Of TEC Temperature Control System

As a new type of temperature control method,Thermoelectric Cooler(TEC)has several advantages,such as simple structure,no pollution in the refrigeration process,high temperature control precision,etc.It has a good application prospect in low power temperature control applications.Usually,the conventional linear PID controller would result in certain problems to the nonlinear systems with large hysteresis,obvious timevarying characteristics and high dynamic characteristics.To solve these problems,a TEC temperature control system combine high refrigeration speed with high stability and good anti-jamming capability is designed in this paper.Focused on the hardware design of the system,this paper applied modularization thinking in design process,including:(1)Select the type of TEC based on its operating parameters.(2)Design the temperature control box according to the working principle of the TEC(3)Design the temperature control circuit based on the STM32 according to the control requirements of the system.The heat transfer model of TEC is complex and the parameter setting of it is cumbersome.In order to solve these problems,this paper uses the modeling method combining mechanism analysis method and experimental identification method to model the system through the input and output of the system,including:(1)Analyze the working principle of TEC and the static relationship and dynamic mechanism of the system through the mechanism analysis method,and obtain the basic mathematical model of the system.(2)Select a reasonable disturbance signal as the system input to obtain the disturbance response data.Seven advanced PSO algorithms are used to identify the parameters of the mathematical model based on the disturbance response data.Then,the optimal mathematical model of system is obtained by comparing the identification results.(3)The accuracy of the mathematical model obtained in(2)is verified by practical experiments.(4)Two conventional PID control schemes are designed for the mathematical model of system.The modeling method used in this paper neglects the influence of complex heat conduction model and has better applicability in different practical scenarios.Aim at the problems existing in conventional PID algorithms,this paper designs a nonlinear PID ADRC algorithm.Both the simulation and experiment indicate that the nonlinear PID ADRC algorithm has fast response speed,higher stability and stronger anti-jamming ability than the conventional PID algorithms for the designed TEC temperature control system,the temperature control system can achieve the temperature controlling accuracy of ±0.1 ?.