Two-switch equaliser for series-connected battery stack using zeta type converter and symmetrical capacitor-diode circuit

Abstract

A two-switch equaliser for series-connected battery stack using zeta type converter and symmetrical capacitor-diode circuit is proposed. The proposed equaliser consists of a zeta type front-end dc-dc converter and symmetrical capacitor-diode circuit, uses only two active switches and two magnetic components, thus it benefits from small circuit volume and flexible for extension. Meanwhile, it can work under open loop, which makes its control simple. Furthermore, high efficiency is achieved by zero voltage switching of all switches. Finally, experimental results of a prototype of the proposed equaliser are presented to verify the analysis results.