Reset compensation applied on industrial heat exchangers

This work aims at improving the control of an industrial heat exchanger used in the thermal treatment in food industry. The goal is to investigate 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 base robust 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 lineal PI compensator to improve transitory response. 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.