An SOC Based Adaptive Energy Management System for Hybrid Energy Storage System Integration to DC Grid

In this paper, an efficient adaptive energy management strategy (EMS) is presented for a hybrid energy storage system (HESS) application to compensate power fluctuation. The HESS consists of a battery and super-capacitor, which are integrated into the DC grid using a modified triple active bridge converter (m-TAB). The conventional EMS uses a low pass filter (LPF) to distribute high and low-frequency components of power. However, the time constant of the LPF is fixed throughout the process, which discharges the battery at the same rate even near the low state of charge (SOC) region. This increases the degradation rate of the battery. The proposed EMS employs an adaptive time constant LPF-based power allocation method to distribute the total power between the energy storage devices. The adaptive feature of the EMS changes the power distribution ratio dynamically to increase the utilization of the super-capacitor and battery operation time, thereby enhancing the life cycle. The proposed EMS is simulated in MATLAB/SIMULINK platform with the m-TAB converter, and the results are compared with the conventional EMS to prove its superiority. The system is also tested on an experimental prototype of 500 W for different test cases, and the outcomes are presented to support the proposed EMS.