결합 인덕터를 이용한 능동형 셀 밸런싱 회로의 밸런싱 속도를 향상시킬 수 있는 새로운 동작 모드

Abstract

This paper proposes a new switching pattern that can improve cell balancing speed in an active cell balancing circuit using a coupled inductor. The circuit operates in flyback and buck-boost mode according to the energy transfer path. In conventional cell balancing method, direct cell to cell balancing is possible when cell balancing is performed between adjacent cells or between non-adjacent odd and even numbered cells. However, when cell balancing is performed between non-adjacent odd-numbered or even-numbered cells, the cell balnaicng process is performed in two steps. This reduces cell balancing speed and circuit efficiency due to increasing the current path. In order to avoid the above demerits, a new cell balancing method is proposed in this paper. The proposed operation can transfer the energy between non-adjacent even- or odd-numbered cells in a single operation like the flyback or the buck-boost operation without the balancing speed reduction. By using the proposed switching pattern, the balancing speed can be improved about 2 times compared with conventional method. The performance of the proposed switching pattern is verified by experiments using a 15 W prototype cell balancing circuit.