Charging/discharging system based on zeta/sepic converter and a sliding mode controller for dc bus voltage regulation

Abstract

This study proposes a charging/discharging system of energy storage devices (ESDs) to regulate the voltage of a dc bus. The proposed charging/discharging system is formed by a zeta/sepic converter and a sliding mode controller (SMC). The SMC uses a single sliding surface to regulate the dc bus voltage for the three operating modes of the charger/discharger converter (charging, discharging, and stand-by) and for ESD voltages lower, equal, or higher than the dc bus voltage. This study includes the stability analysis of the SMC and a design procedure of the SMC parameters. The charging/discharging system is simulated in PSIM, where the results confirm that the proposed SMC regulates the bus voltage in charging, discharging, and stand-by modes for different operating points of the system. Finally, the proposed charging/discharging system was constructed for demonstrating the feasibility of the solution for real applications. Moreover, the experimental results obtained in such a platform put into evidence the accuracy of the proposed SMC in regulating the bus voltage in all the possible conditions: Bus voltage lower, equal or higher than ESD voltage, and during charge, discharge, and stand-by modes of the ESD.