Modeling and control of a dual cell link for battery-balancing auxiliary power modules

This paper focuses on the design of current controllers of a half-full bridge balancing link for a battery-balancing auxiliary power module. The fundamental concept of the converter is explained, e.g. phase shift control. For steady-state operation while the cells are unbalanced, a duty cycle adjustment is introduced to make inductor VA balanced. The proposed topology offers four typical balancing modes, including cells to auxiliary, cell to cell and auxiliary, auxiliary to cells, and cell to cell. They are realized by properly controlling leakage inductor current and output power from the half-full bridge. The average model of the topology and the linearized output power characteristic are derived to help choose the current controller gains. High-fidelity validation results are shown to verify the controller design and mode switching given the cell current demands.