Multiport DC–DC Converter With Integrated Cascaded Structure for Optimizing Centralized Battery Equalization System

Existing centralized equalization methods can only equalize one battery cell at a time, which is the main reason that limits the equalization speed and practicability of such methods. To overcome this limitation, this article proposes an integrated cascaded multiport converter (ICMPC) to optimize the structure and performance of the centralized equalization system. Through the proposed converter, the simultaneous and single-stage energy exchange between multiple unbalanced cells and the battery string can be achieved, so as to effectively improve the equalization speed. Meanwhile, the number of ports of the ICMPC is easy to expand, and the optimized system possesses the advantages of compact structure, high efficiency, and high cost effectiveness compared with conventional methods. As the basic and typical form of the ICMPC, the integrated cascade three-port converter is analyzed as an example in terms of operation principle, parameter design, and zero-voltage switching analysis. Finally, to confirm the theoretical analysis, a laboratory prototype is designed, and a comprehensive comparison is performed. The experimental and comparative results fully prove the practicality and superiority of the proposed ICMPC-based centralized equalization.