Supercapacitor-based energy storage system with voltage equalizers and selective taps

A supercapacitor-based energy storage system, with which high efficiency and high energy utilization ratio of supercapacitors (SCs) can be realized, is proposed. This system consists of voltage equalizers and selective intermediate taps. Output voltage variation is limited to a particular range by the selective intermediate taps, while voltage imbalance of SCs due to charging/discharging through these taps is minimized by the equalizers. This paper presents operating principles and experimental performance of the proposed energy storage system.