Charge-Equalization Circuit with Single Resonant Energy Tank for Series Batteries

A charge equalization circuit with a resonant energy tank is designed for series-connected batteries with associated selective switches. The resonant energy tank formed by an inductor and a capacitor is used as an intermediate energy tank. The charge balancing action is performed by sequentially activating the selective switches attached to the designated batteries to transfer the charge obtaining from the battery with a higher potential to the lower-potential battery. With repeated charge transference, charge equalization can be accomplished eventually. Experimental verifications have been made on a laboratory circuit of a battery power source with four series cells.