Optimizing Fractional Order PID Control for Green Hydrogen Ammonia Synthesis Tower Temperature

Renewable energy offers the benefits of ecological harmony and enduring progress. However, due to its inherent volatility, the temperature in the ammonia synthesis tower fluctuates during the green hydrogen synthesis ammonia process. To address the issue, a temperature control method for the ammonia synthesis tower based on Fractional Order PIλDμ (FOPID) is proposed. Firstly, the ammonia synthesis tower model is established, and a cascaded control strategy for the hot spot temperature system is determined. Secondly, an Optuna optimization algorithm, employing an adaptive evolutionary strategy sampler based on the covariance matrix, is introduced to optimize the parameters of the FOPID controller. Comparative simulations of the temperature control system in the ammonia synthesis tower reveal the enhanced performance of the PIλDμ controller optimized through Optuna, surpassing traditional PID methodologies. Under PIλDμ controller, the system overshoot is reduced by 2.6%, the settling time is reduced by 5.9%, and the system's setpoint tracking capability, disturbance rejection ability, and robustness are improved.