Implementation of anti windup scheme on PID controller for regulating temperature of glycerin bleaching process

Controlling slow dynamic process such as temperature for glycerin bleaching process is inherently difficult. This is due to the unfavorable characteristic of the system that possess nonlinearities caused by actuator constraint that will lead PID controller produces unsatisfactory performance due to windup phenomenon. This paper presents the implementation of the anti windup scheme on a PID controller to prevent the PID from windup phenomenon. For this purpose, back calculation anti windup scheme is attached to the PID controller as to improve the performance of PID controller in regulating temperature for glycerin bleaching process. The process are modeled using first order plus dead time (FOPDT) model and for determinations of PID parameter the Ziegler-Nichols (ZN) tuning formulae is used. Both of the controller, which is PID without and with anti windup was evaluated and compared via simulation and real time implementation. The analysis of the performance was based on percent overshoot, rise time, settling time and time to recover load disturbances. The results denote that implementation of back calculation anti windup on PID does significantly improve the PID controller and provide satisfactory performance in regulating temperature for glycerin bleaching process.