Modularized battery cell voltage equalization circuit using extended multi-winding transformer

This paper proposes a new circuit for equalization of battery cell voltage. Proposed circuit is using extended multi-winding transformer. This circuit achieved the balancing operation between the modules by connecting the winding between the transformers. Cantilever transformer model is used to analyze the balancing performance. And the balancing deviation between the modules is drawn through this model. Contrary to the conventional circuit, the advantage of proposed circuit is easy to modularize and control and the number of batteries is not limited. This point can be important advantages to balanced many series connected battery cell voltages in applications such as HEV required the high voltages. This paper analyzed the proposed circuit theoretically. And to verify the proposed circuit, the prototype board is designed and implemented. Experimental results verify that this circuit achieved the good battery cell balancing performance.