Temperature control of electric hotplate based on Smith fuzzy multi-level integral separation PID

In order to improve the processing yield of large-size wafers, the partition control method of silicon carbide wafer heating plate heated by metal oxide conductive coating is studied, and a 4-partition temperature control system based on Smith fuzzy multilevel integral separation PID is proposed so as to solve the surface temperature consistency of the wafer heating plate under the requirement of high precision. Through the thermal effect simulation to establish the system model, the heat distribution in each region is analyzed. And then the heating plate temperature control system based on PLC controller is built, and Smith fuzzy multilevel integral separation PID algorithm to facilitate the practical application to improve the control accuracy is proposed, combined with the system model and the conventional PID algorithm in MATLAB for comparison. Finally the experimental verification is carried out based on the established heating plate temperature control system. Simulation and experimental results show that the present control method has a higher control accuracy, and can realize the consistency of the surface temperature of the heating plate stabilized at about 0.05℃, the average temperature steady-state error ±0.05℃, and the control effect is good.