An Energy Management Algorithm for Parallel Hybrid Energy Storage Based Isolated and Grid Connected System

The inclusion of supercapacitor with battery not just improves the system performance but also enhances the reliability and life cycle of the system. A parallel connection of supercapacitor and battery based Hybrid Energy Storage System (HESS) reduces one DC/DC bi-directional converter and control circuitry associated with it. However, a proper scheme to utilize this parallel HESS in an AC/DC microgrid is not present in the literature. This article presents an energy management algorithm for a parallel connected battery supercapacitor based HESS for residential smart building application. The article also presents the design of HESS for a smooth transition of battery current. The proposed energy management algorithm consider multiple modes of operation depending on grid peak pricing, state-of-charge of battery, grid connectivity, MPP mode of PV, and load shedding of non-critical load in deficit power mode. The reference current for all the available sources are generated using the proposed algorithm and the control is designed to operate the system uninterruptedly in all the modes of operation. Further, the dynamic and steady state performance of the proposed control strategy has been verified through theoretical analysis and digital simulation studies using MATLAB/Simulink.