Reset compensation for temperature control: Experimental application on heat exchangers

This work aims at improving the control of an industrial heat exchanger by using reset compensation. The goal is investigating the potentials of a hybrid compensator previously developed by the authors, the PI+CI reset compensator, in the robust control when significant uncertainty is present. To this end, a PI+CI compensator has been designed by using a two step method: firstly, a robust base PI compensator is tuned by using the Quantitative Feedback Theory to satisfy (robust) relative stability and tracking specifications; and secondly, a partial reset action is added to the base lineal PI compensator to improve transitory response. In addition, a PI compensator is tuned by using the Internal Model Control for comparison purposes. Finally, the reset conditions are simply modified in the PI+CI compensator to overcome the effect of the dominant time delay over the reset action, through the introduction of a reset band which can have fixed or variable values along the time.