Nondissipative current diverter using a centralized multi-winding transformer

Series connected battery strings are prone to dramatic reduction in life if individual cells are not maintained at the same charge level. This can be achieved by diverting the excess energy around fully charged cells while continuing to charge undercharged ones. Nondissipative current diverters provide a means to divert the charging current away from a fully charged cell to the weak cells in the stack in a nondissipative manner. This allows the rest of the stack to be fully charged while avoiding overcharging healthy cells. This paper presents a new technique for equalizing a series battery stack using a nondissipative current diverter.