Investigations on balancing circuits for supercapacitor modules

Supercapacitors or Electrochemical Double Layer Capacitors, briefly named EDLC, are very promising energy storage components for applications in automotive industry where are intended to be parallel connected to lead-acid or Li-ion batteries or fuel cells. At the beginning of development are the applications in green energy domain, for storage purposes. The need for higher rated voltages of capacitors makes necessary the construction of modules using series connection. The balancing circuits that are investigated in this paper look to prevent the overcharging of capacitors that can occur in the charging process due to inherent uneven parameters of individual supercapacitors. The active balancing circuit that is presented is a cost-effective solution that brings benefits over the simple passive methods for balancing, especially for high power applications.