Coordinated control of a solid oxide fuel cell system based on Newton-Raphson and active disturbance rejection control algorithm

Solid oxide fuel cells (SOFCs) are a pivotal technology for mitigating energy shortages, where precise thermal management and power regulation are essential. Their performance and safety critically depend on operating temperature and load-following capability. However, conventional control strategies are hampered by sluggish dynamic response, inadequate regulation under high-power or large-load variations, and reliance on time-consuming trial-and-error parameter tuning, which collectively degrade performance. The study develops an advanced Newton-Raphson-based optimizer active disturbance rejection control (NRBO-ADRC) strategy to address these limitations. A validated SOFC system model and a subsequent dual-loop multivariable control framework are established. This framework characterizes the relationship between operating temperature and a fixed polarization voltage (0.85 V) under varying power demands, enabling coordinated control of target power, temperature, and voltage through air and fuel flow regulation. Evaluated against conventional ADRC and PID-ADRC under step-change and realistic random disturbances, the proposed strategy demonstrates superior performance. At 60 kW target power, adjustment times are reduced by 57.5% and 46.2% compared to PID and ADRC, respectively, with overshoot limited to 0.5%, which is corresponding to reductions of 58.3% and 44.4%. Under disturbances, the power control elative error of NRBO-ADRC reduce 30.9% and 12.2% than PID and ADRC, and the relative error of NRBO-ADRC is 1.37% and 1.31% to temperature and voltage control, which is decreased 41% and 44% than PID, and dropped 25% and 27% than ADRC. The NRBO-ADRC strategy significantly enhances dynamic response, overshoot suppression, and robustness, providing an effective reference for multivariable control in high-power SOFC systems and contributing to advances in distributed power generation.