Ripple-Free Bidirectional DC–DC Converter With Wide ZVS Range for Battery Charging/Discharging System
Zhixing Yan, Jie Li, Shikai Xu, Ningrui Yang, Jun Zeng, Junfeng Liu, Weibin Wu, Renjun Hu, Haixia Qi
Abstract
A ripple-free bidirectional dc–dc converter with wide soft-switching range is proposed for battery charging/discharging application in this article. On battery side, the current ripple can maintain zero by two-phase interleaving technology in spite of the battery voltage and transfer power variation. Through series connection, high voltage conversion ratio and reduced voltage stresses of switches can be achieved effectively. The built-in transformer technology allows for a small magnetic component size, due to its inherent saturation avoidance. With the proposed control law, the control variables can be decoupled. The duty cycle is fixed by battery side voltage while the transfer power can be regulated monotonously by phase-shift angle. Theoretical derivation illustrates that soft switching can be obtained in all switches by adopting proper parameter design. Furthermore, comparative analysis shows the proposed converter is suitable for battery charging/discharging applications. The experimental verification proves the merits of the proposed converter by a 40-60V/400V 1-kW prototype.