Bidirectional BuckBoost Converter With Reduced Power Loss and No Right-Half-Plane Zero

This article presents a novel hybrid bidirectional buck-boost converter (HBBC) for lithium-ion battery management. Unlike the conventional four-switch buck-boost converter (FBBC), whose power efficiency is greatly limited at heavy loads mainly due to high conduction loss from a high dc resistance (DCR) inductor, the proposed HBBC adopts assisted capacitive paths to reduce the current stress on the main inductive path. Thus, the conductive loss of inductor's DCR is greatly reduced in both the buck and boost modes. To verify the effectiveness of the proposed structure, detailed analyses on both the loop performance and conduction loss are provided. Compared with FBBC, the conversion efficiency of the proposed HBBC is increased by 23.3% in the boost mode, and the peak efficiency is up to 97.8% with an adopted inductor with a DCR of 270 m Omega.