Desalination, Vol.458, 122-135, 2019
Super-twisting sliding mode control and robust loop shaping design of RO desalination process powered by PV generator
Reverse osmosis (RO) desalination technique is the most widely used technology for supplying fresh water since it offers many advantages. Developing an accurate control strategy is one of the most challenging jobs in RO desalination plant especially under uncertainties and disturbances conditions to avoid all possible system failures and damages for safe operations. This paper presents an overall architecture of reverse osmosis desalination process supplied by a stand-alone photovoltaic (PV) system. A dynamic modeling of various components of this architecture is developed. A control strategy of the whole system is addressed with a controller for each part. Furthermore, special attention is given here to the robust control design of reverse osmosis (RO) membrane to address large set point changes and capability to reject external disturbances and to cope with parametric uncertainties as variations in feed water salinity. The control block is divided into two loops the first one using the loop shaping design method and the super-twisting sliding mode control is applied for the second loop. Simulation results investigating different scenarios show the efficiency of the proposed scheme.