Single‐magnetic equaliser without any sensors for series‐connected battery strings

Abstract

This study proposes an automatic cell-to-cell equaliser to balance the battery voltages in series-connected battery strings. In the proposed equaliser, each cell needs only one MOSFET, and the adjacent cells share the transformer winding. The voltage balance is automatically realised by using a pair of complementary control signals with a fixed duty cycle. What's more, no sensing circuit is required. Consequently, the proposed equaliser is cost-effective and easy-to-realise. The circuit topology and operating principles are firstly presented. Then the voltage balance analysis is given in detail. Moreover, a design guide is also given by considering four lithium-ion cells. Finally, the validity of the proposed equaliser is verified by experimental results.

Performance and comparison of equalization methods for lithium ion batteries in series

“…22 Significant research has been carried out on active equalization. Liu et al 23 introduced a cellto-cell equalizer to balance battery voltages by using a pair of complementary control signals with a fixed duty cycle. Shang et al 24 proposed an automatic cell-to-cell battery equalizer consisting of forward and fly back converters through a multi-winding transformer.…”