A New Sort of Equalization Circuit Based on Coupled Inductors for Series-connected Battery Strings

An active balancing circuit for equalization of series-connected cells is proposed. The proposed circuit achieves direct balance in Single Mode or Blending Mode by constituting Buck-Boost converter or flyback converter with the help of bidirectional low-frequency switches and high-frequency ones. Theoretical calculation is carried out to explore the relationship between circuit parameters and equalization effect. In order to further improve circuit's performance, a balancing strategy and controlling methods containing maximum efficiency control and maximum power control are analyzed. To verify the operation of the proposed circuit, simulation experiments are performed under different working conditions.