Renewable Energy System for Small Water Desalination Plant

In this work, two standalone configurations of hybrid renewable energy system for low power desalination plant are designed and their performances are presented. The design of both systems is based on datasheet driven wind turbine, solar photovoltaic (PV) panel and battery models. Reverse osmosis (RO) desalination process is used which is composed of a module with semipermeable membranes and an electric motor for pumping water under high pressure. Each energy system is designed to meet the power demand of its corresponding electric motor. Three-phase diode rectifier, two dc-dc boost converters and a buck-boost converter to manage the energy flow of the battery bank are applied in both configurations. In one of these configurations the converters form up the dc bus voltage that feeds a two-level three-phase pulse-width modulated (PWM) inverter for driving the ac motor. Distinctively in the other one, an integrated structure combining classic boost converter and Greinacher/Cockcroft-Walton rectifier is proposed to perform the voltage step-up function. The resulting dc bus voltage is applied to a three-phase three-level Neutral-Point Clamped (NPC) PWM inverter. Performance analysis were carried out by simulations under specific limits of wind and solar irradiation levels to meet load demands. Experimental results of the proposed dc-dc arrangement are shown to evaluate its practicality and possible benefits.