Performance analysis and PID control strategy optimization of the electronic expansion valve on the single-tube heat exchange experimental platform

In this paper, the fuzzy strategy is used to optimize the electronic expansion valve (EEV) PID control on the single-tube heat exchange experimental platform (STHEEP). The control strategy is implemented through LabVIEW. The EEV serves as the control object, and the superheat degree is the control target parameter. A comparative analysis of the control performance and heat exchange performance with the two different PID control strategies is conducted to optimize the EEV control. According to the results of the experiment, using fuzzy strategy to optimize the PID control shows significant effects, leading to a high improvement in the performance of the experimental platform. Compared with the routine PID control (RPIDC), the overshoot of the fuzzy PID control (FPIDC) is reduced, the regulating time is shorter, and the fluctuation range of the superheat degree is smaller. In the steady state stage, the average heat exchange coefficient of the test section with FPIDC is higher than that with RPIDC. The FPIDC provides higher control precision, and the energy consumption during the experimental regulating process is lower. Therefore, the optimized fuzzy PID control strategy of the EEV can be used as a preferred option in future research on superheat degree control.