DESIGN OF ROBUST SISO PI CONTROLLERS FOR A MSF DESALINATION PLANT

The method of inequalities is applied to the of design a robust PI con troller for a multi-stage flash (MSF) desalination plant. The method t akes into account the given variations in process gain, time delay and time constant (K-p, tau(d) and tau) of the transfer function models. The performance of the closed loop system is evaluated for different o perating points (i.e., on different transfer function models). PI cont rollers are also designed using an internal model controller (IMC) and by Ziegler-Nichols (Z-N) methods based on the nominal transfer functi on model. The performances of these controllers are compared. The cont roller designed by the method of inequalities gives the best results.