Fast and Accurate Balancing Methods based on Flyback converters for Series-connected Supercapacitors

This paper investigates fast and accurate balancing methods for series-connected supercapacitors using flyback converters with two-winding transformers. Series-connection of supercapacitor cells requires voltage balancing due to electrical differences, which, if unmanaged, lead to cell degradation and reduced performance. Two flyback-based balancing circuits—unidirectional and bidirectional—are explored. While both circuits effectively balance cell voltages, the bidirectional method demonstrates significantly faster performance by directly transferring energy between overcharged and undercharged cells. Simulation and experimental results validate the superior efficiency of the bidirectional method, reducing balancing time and avoiding overvoltage issues during charging.