An Any-Cell-to-Any-Cell Battery Equalizer Based on Half-Bridge LC Converter

Abstract

This letter proposes an any-cell-to-any-cell battery equalizer based on the half-bridge <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> converter. Cell-to-cell, cell-to-multicell, multicell-to-cell, and multicell-to-multicell balancing modes can be flexibly realized regardless of the number and location of target cells. The energy transfer between cells is controlled by modulating the fundamental harmonic voltage for each half-bridge. Meanwhile, the equalizer benefits from the resonant operation and uses the small-capacity passive components to realize lower cost and smaller size. In addition, an easy-to-realize modular structure is presented to enhance the circuit extensibility. The prototypes for five cells and three modules (nine cells) are built and tested. Experimental results confirm the validity and characteristics of the proposed equalizer.