Cell-to-cell charge equalization converter using multi-winding transformer with reduced number of windings

In this paper, a charge equalization converter using a multi-winding transformer is proposed. The proposed scheme achieves the cell-to-cell charge transportation by buck-boost and flyback operation. In this operation, adjacent two cells share a current path or secondary tap of multi-winding transformer. Therefore, the number of windings cuts in half in comparison to conventional multi-winding charge equalization converter, resulting small circuit size. To verify the operation of the proposed charge equalization converter, experiment for lithium-ion battery stack is performed.