Energy bus-based equalization scheme with bi-directional isolated Cuk equalizer for series connected battery strings

A bi-directional isolated Cuk equalizer for the energy bus-based equalization network is presented in this paper. The battery side is isolated from the bus side by two isolated capacitors. A synchronous approach for Cuk equalizer is used to improve equalization efficiency. The equalization efficiency can achieve above 90% in a wide range of equalization power. The operating principle, steady-state analysis and derivation of synchronous conditions have been made to show the merits of the equalization scheme. The validity of this equalization scheme and synchronous conditions has been verified by experiments.