Fractional-Order Low-Frequency Compensators for Processes with Ramp-Like Disturbances

This study investigates the use of fractional order double integral compensators to track ramp-like disturbances without steady state offset. The reason causes these kind of disturbances; especially in plantwide processes; refers back to the presence of time scale difference between two interacting systems. The effectiveness of fractional order low-frequency compensation in improving the performance of PI controllers is demonstrated first through a rigorous simulation involving the Continuously Stirred Tank Reactor (CSTR) as a chemical plantwide system, and secondly through a real time Peltier thermal process. The fractional order double integral compensator shows superiority in tracking ramp-like disturbances.