Simultaneous power and data transfer over common bus using talkative bidirectional flyback converters for battery equalization

Cell inconsistency is an inherent challenge for lithium-ion batteries during long-term operation, necessitating the use of battery equalization systems (BESs). In such systems, real-time data communication is essential for ensuring accurate system coordination and effective equalization performance. This paper proposes a distributed BES based on the talkative power converter (TPC) technique, employing a bidirectional flyback converter as the core equalization unit. In the proposed approach, the converter not only transfers energy among distributed battery modules but also modulates data signals for communication. This dual-function design eliminates the need for additional communication hardware or dedicated signal transmission circuits, thereby reducing the overall system complexity. On this basis, a distributed equalization system and its communication channel model are developed. The system noise sources are then analyzed and a noise suppression strategy is proposed to improve the communication reliability. Furthermore, a practical communication protocol tailored to the distributed architecture is designed. Finally, a hardware prototype is constructed and tested, achieving real-time data communication at a rate of 8.33 kb/s. The results verify the feasibility of using switching-ripple-based power and signal dual modulation for communication within distributed BESs.