A new two-switch flyback battery equalizer with low voltage stress on the switches

In this paper, a new battery equalizer applying two-switch flyback topologies is proposed. Since the proposed circuit is based on two-switch flyback structure, voltage stress on the switches can be clamped at the battery stack voltage level. Furthermore, the number of active devices is minimized by using a common switch and a common clamping diode. The operational principle, theoretical analysis, design consideration, and implementation method are presented. In addition, to confirm the performance of the proposed battery equalizer, experimental results from four 3.9 V and 2600 mAh lithium-ion batteries are presented.