A modular converter with embedded battery cell balancing for electric vehicles

New topologies of switching power converters could improve the efficiency of the energy conversion of battery electric vehicles, by achieving low cell unbalance and reduced harmonic content of the output currents. This article proposes a modular multi-cell converter with embedded cell balancing for battery electric vehicles. In this new topology, the series connection of the cell is obtained by means of chopper cells, allowing the highest flexibility for the discharge and recharge of each individual cell. The balancing algorithm is presented and discussed in the paper, showing that the converter is capable of producing symmetric three-phase voltages with low harmonic content even for significantly unbalanced cells. The modular multi-cell converter is simulated for the application to a city car to demonstrate the main features of the balancing algorithm and the technical features of the proposed converter.