Active cell balancing circuit for series-connected battery cells

This paper proposes a cell-balancing circuit for a series-connected battery string. The proposed cell equalizer is an active cell-balancing circuit with a multi-winding transformer based on a forward DC-DC converter. The advantage of the proposed cell balancing circuit is that it can use less number of active power switches than other forward converter circuits. The proposed circuit operates for all cells to be equalized simultaneously. Thus, this balancing circuit is faster than a bi-directional forward converter in the literature. This paper presents a simulation study to verify the feasibility of the proposed circuit with PSIM simulation software. Simulation results proved that each initial unbalanced cell is equally balanced by the proposed cell-balancing circuit.