Self-Tuning PI Controller For a Fuel Cell Micro-Cogeneration System

This study presents the temperature control of High Temperature Shift (HTS) reactor within a Polymer Electrolyte Membrane (PEM) fuel cell based micro-cogeneration system. A Proportional-Integral (PI) controller was used for this purpose. Novel tuning rules were proposed for the PI controller. Also, a self-tuning controller structure was integrated into the design in order to cope with certain changes in operating conditions such as setpoint changes, load disturbances and parameter uncertainties. Unlike the most used tuning methods in the literature, designed controller is rather practical, not compromising the "response with no overhoot" criterion and depends totally on the model parameters as tuning parameters. Thus, the controller parameters could directly be determined from the model parameters without calculation of an extra variable. By the proposed self-tuning controller, the output response tracked the varying setpoint without any overshoot and with some tolerable overshoot in the existence of load disturbances. The desired catalyst temperatures were ensured with no steady-state error and no sudden control signal, making the controller applicable for industrial processes.