Design of parallel cascade controller for nonlinear continuous stirred tank reactor

This work presents an approach to control the temperature of a nonlinear continuous stirred tank reactor (NCSTR) through parallel cascade control structure (PCCS). For the first time, PCCS is used to control the temperature of NCSTR by (1) modelling the dynamic behavior of CSTR with a recirculating jacket heat transfer system into a third order unstable transfer function and (2) using the model matching technique to synthesize the controller parameters. The controller of the secondary loop of PCCS is designed to achieve enhanced regulatory performance whereas, the primary loop controller is designed for better setpoint tracking. The closed loop performance of the proposed method is evaluated by carrying out simulation on the differential equation of the NCSTR and comparing it with other structures such as series cascade control structure (CCS) and parallel control structure (PCS). The response shows that the proposed method provides satisfactory performance in nominal, perturbed and noisy conditions.