Parallel balancing converter for serially connected batteries string

This paper introduces a new isolated converter topology for parallel balancing of serially connected batteries string. The system uses a low voltage bus capacitor as an energy buffer that is common for all the cells and balancing of the string is achieved by voltage equalizing of the cells. Each converter is in charge of balancing three adjacent cells, reducing the components count of the system. The converter operates in DCM and the current that flows between the cells and the bus is a function of their voltage difference. As a result, the quiescent power loss is minimal since no energy circulates in the system when the cells are balanced. Furthermore, no voltage or current sensors are required, making the implementation of the system simple and cost-effective. Theoretical analysis as well as design guidelines for the construction of the new topology are detailed and validated by experimental results that demonstrate the system's balancing capability.