Umudike Journal of Engineering and Technology

Proton Exchange Membrane Fuel Cells (PEMFCs) are attractive clean-energy technologies. However, their nonlinear dynamics and coupling among variables pose substantial control challenges. To address these challenges, this study investigates the controllability of PEMFCs and designs an Internal Model Control tuned PI (IMC-PI) controller. A reduced-order PEMFC model for hydrogen (H2) and oxygen (O2) gases was developed, assuming steady-state water pressure dynamics The steady state water pressure dynamics was maintained by the introduction of a variable that cancels out its dynamic. Model controllability was assessed using the Popov-Belevitch-Hautus (PBH) criterion and the controllability Gramian. Proportional-Integral (PI) and Internal Model Control-based PI (IMC-PI) controllers were implemented for reference tracking of hydrogen and oxygen partial pressures. For the hydrogen channel, IMC-PI and PI systems have rise times of 0.005 seconds and 0.020 seconds, respectively, along with settling times of 0.005 seconds and 0.040 seconds, respectively. Additionally, the ISE error indices were 1.04 × 10⁻⁵ and 9.22 × 10⁻⁵, respectively. Similarly, for the oxygen channel, IMC-PI and PI controllers have a rise time of 0.002 seconds and 0.010 seconds, respectively, with settling times of 0.010 seconds and 0.020 seconds, respectively, with absent of overshoot. These results show that IMC-PI achieves faster rise and settling times, eliminates overshoot, and reduces error indices more effectively than traditional PI control. The findings showed that IMC-PI tuning offers a more effective and robust method for ensuring the stable and efficient operation of PEMFCs and it is therefore recommended not only for practical PEMFC control applications but for future experimental validation and integration with advanced control strategies.