Energy storage system based on supercapacitors with an unregulated dc-dc converter and selective intermediate taps

A novel supercapacitor (SC)-based energy storage system comprising a combination of an unregulated dc-dc converter and selective intermediate taps, with which SCs can discharge efficiently and deeply, has been designed, assembled, and tested. The output voltage to the load is roughly regulated by the selective intermediate taps while a high utilization ratio of SCs is achieved by the combination. The operational principles and experimental discharge/charge cycle performance are presented in this paper.