Voltage balancing controller for automotive lithium ion batteries using bidirectional zero-voltage-transition multi-port converter

Bidirectional multi-port converters are particularly suitable for voltage balancing controllers of automotive lithium ion batteries. The converter topology proposed in this paper achieves a small number of components, high efficiency and low EMI due to the zero voltage switching. In comparison to other applications with multi-port converters the voltage balancing controller application requires a multi-port converter with a large number of input-output ports. A general analysis of the energy transfer of the proposed multi-port converter has been developed and a decoupling control strategy has been developed. A prototype converter has been built and tested to verify the concept. Measurements are in good correlation with theoretical predictions.