Study on Multivariable Decoupling Control of Small PWR Pressurizer based on Active Disturbance Rejection Control

Since the pressurizer (PZR) in a small pressurized water reactor (PWR) features non-linearity, time-dependence, and strong coupling, its accurate mathematical model is hard to build and the traditional control method cannot provide a satisfactory control effect. Therefore, this study describes a multivariable decoupling control method based on the active disturbance rejection control (ADRC) technique for such PZR. In this study, a non-equilibrium three-region model of PZR is built, and processed linearly based on the perturbation theory to generate the pressure and water level coupled transfer function equation. Then, an ADRC based decoupling controller is designed based on the transfer function, and the parameters of the controller are subjected to multi-objective optimization via differential evolution. Finally, the ADRC based decoupling control and traditional proportional-integral-derivative (PID) control for the same small reactor PZR are compared and analyzed by the MATLAB simulation platform. As demonstrate by the comparison, the ADRC based decoupling controller can effectively solve the PZR pressure and level coupling problem and has better robustness and interference immunity than the traditional PID controller. Therefore, this study provides a theoretical foundation for the engineering application of the ADRC method to the PZRs.