A Single-Switch Equalization Charger for Series-Connected Energy Storage Cells

Abstract

Series-connected energy storage cells require cell equalizers in order to mitigate cell voltage imbalance. Conventional cell equalizers, however, consist of a number of switches or transformers that are considered not preferable in the viewpoint of circuit complexity and reliability. This paper proposes an equalization charger that consists of a single switch and passive components. Experimental performance tests showed that series-connected EDLCs could be charged up to the uniform voltage level by the proposed equalization charger though the initial voltages of the EDLCs were imbalanced.