Robust temperature control of MSF desalination plants with coefficient diagram method

Design of a controller sufficiently robust to the parametric uncertainties for the plant parameters is an important problem. Coefficient diagram method (CDM) is shown to be an efficient control technique to solve this problem. The controller design by CDM is based on the choice of the coefficients of the characteristic polynomial of the closed loop system according to the convenient performance criteria such as equivalent time constant, and stability indices. In this study, the controllers are designed for three temperature loops of large multi-stage flash (MSF) desalination system by using CDM; then, obtained time domain characteristics are compared with the results of some other methods, It is shown that CDM design is more stable and robust whilst giving the desired time domain system performance.