An integrated battery charger for EVs based on an asymmetrical six-phase machine

The paper considers a novel battery charger topology for electrical vehicles (EVs) that utilises an asymmetrical six-phase propulsion machine. A six-phase inverter and the machine are fully integrated into the charging process. The proposed integrated battery charger has the advantages of unity power factor operation and zero average torque production in the machine during the charging mode. The operating principles are based on the additional degrees of freedom that exist in multiphase machines and it is shown that asymmetrical six-phase machines can be conveniently utilised to achieve charging through the machine´s stator winding while developing zero electromagnetic torque. Detailed theoretical analysis is reported for the asymmetrical six-phase charging system. A mathematical model of the six-phase voltage source rectifier (VSR) is given, control in the charging mode is discussed, and the theoretical considerations are validated by simulations.