Up–Down Converter for Energy Recovery in a CDI Desalination System

One of the newest methods for desalinating water is capacitive deionization (CDI). This technology is based on carbon electrodes capable of adsorbing ionic components from water. The aim of this paper is to present the power electronic stage required in a water desalination system that permits recovery of part of the energy involved in the process and its reuse in a high efficient manner. First, the CDI process and the energy recovery are described. Second, a buck-boost converter is designed that allows energy to be recovered while taking into account the large voltage variations at its input and output. The converter is modeled using a mathematical algorithm to study its behavior with large input and output capacitor values. Simulation results are provided as well as experimental data agreeing with them.