Integral Action for Bilinear Systems With Application to Counter Current Heat Exchanger

In this study, we propose a robust control strategy for a counter-current heat exchanger (HEX). The primary objective is to regulate the outlet temperature of one fluid stream by manipulating the flow rate of the second counter-current fluid stream. By leveraging the energy balance equations, we develop a structured bilinear system model derived by using a uniform spatial discretization of each stream into a cascade of homogeneous volumes and by considering the heat transfer and convective phenomena within the exchanger. We introduce two control strategies: 1) an output feedback controller incorporating a state observer and 2) a purely integral control law. The effectiveness of the proposed control strategy is validated through real experiments on a real HEX.