Modulation and Control of Series/Parallel Module for Ripple-Current Reduction in Star-Configured Split-Battery Applications

Split-battery converters based on cascaded H-bridges (CHBs) are gaining popularity due to their excellent physical modularity. During operation, however, the batteries experience substantial current ripple. Conventional ripple-current reduction methods rely on bulky passive components or complicated control. This article presents modulation and common-mode voltage injection methods for cascaded double-H-bridge converters (CHB
²
). The control methods directly mitigate the source of the ripple current—the fluctuating arm power—by exploiting the parallel interconnection across the CHB
²
arms. In the lab setup, the proposed solution approximately halves the battery current ripple compared to the CHB counterpart. Finally, this article studies component sizing and limitations of the proposed solution.