Dynamic Modeling and Nonlinear Control of Solid Oxide Fuel Cell

Abstract

In this study, the model dynamics of a solid oxide fuel cell (SOFC) is studied and verified with available literature data. The dynamic model is simulated in MATLAB/Simulink. To facilitate the system operation by regulating its inputs and outputs, a nonlinear observer based sliding mode controller (SMC) is synthesized and implemented. The sliding mode technique is preferred since the model‐based control structures are expected to provide better closed‐loop performance than conventional control technique. The two outputs of the system namely temperature and voltage are proposed for control at the desired operating conditions. For better system performance, these two outputs are necessary to be maintained at nominal operating conditions since they deviate due to known and unknown disturbances. To test the designed controller, the performance is checked when the desired operating condition varies in a pulse pattern. Servo‐type closed‐loop analysis shows that the model‐based SMC tracks setpoint changes better than the proportional and integral (PI) controller. The SMC is also tested against uncertainties and structural mismatches, demonstrating superior stability in maintaining operating temperature and voltage of SOFC. Overall, the observer‐based SMC performance is found superior to the PI controller, as confirmed by satisfactory quantitative error analysis. Furthermore, a comparative analysis with model predictive control (MPC) is also conducted which demonstrates that the proposed SMO‐SMC achieves lower temperature tracking error and comparable voltage regulation performance, while maintaining a simpler implementation structure.