Charging-balancing circuit design of series-connected electric double-layer capacitors in high power applications

Abstract

The high power source which is included Electric-Double Layer Capacitors (EDLC) has been configured to generate power higher than limited power. Rated voltage of EDLC has low maximum value that's why it must need series-connection in high power applications. When EDLCs are series-connected, each cell has an unbalance voltage by each tolerance. Unbalance phenomenon is one of the facts reducing their life expectancy. Balancing or equalization is much studied in past years, but it is mostly not for high power applications. Hence, charging-balancing circuit of series-connected EDLCs is designed to equalize each cell and module voltages in this paper. It is not only discussion of circuit behavior but EDLC modeling of equivalent circuit which is considered parasitic elements causing voltage unbalance. Proposed balancing circuit mitigates voltage unbalance of EDLCs, as a result of charging-balancing circuit verified with simulation. Through the results, EDLC could be utilized in high power applications such as pulsed power, prime power source, hybrid electric vehicle.