Supercapacitor voltage based power sharing and energy management strategy for hybrid energy storage system

Abstract

Integrating batteries accomplishes a highly reliable, efficient, and durable photovoltaic (PV) DC microgrid. Supercapacitors (SC) boost the dynamics and battery life even further, and such a combination is known as a hybrid energy storage system (HESS). The control and power splitting between the battery and SC plays a crucial role in the operation of the HESS. The most common power routing method is constant bandwidth low pass filter (LPF), the drawback of which causes slow dynamics of the control loop and significant variation in SC operating voltage leads to ringing in the DC bus voltage. Hence, this work proposes a power management scheme with a variable bandwidth filter for HESS and a power splitting control strategy to eliminate the sluggishness imposed on the battery control loop by LPF. The proposed approach has several advantages over the conventional method, including efficient SC utilization, improved battery life, and better DC bus voltage regulation. The proposed scheme is validated using simulation results. Hardware tests have been carried out to verify the proposed system’s accuracy and viability.