An eight-switch-converter-based motor drive and onboard battery charger for EVs incorporating symmetrical six-phase machines

<p dir="ltr">This paper proposes a novel powertrain configuration for electric vehicles incorporating symmetrical six-phase machines, based on an eight-switch voltage-source converter. The proposed configuration leverages the spatial phase opposition of symmetrical six-phase machine windings to perform propulsion and onboard battery charging functions with minimized system component count. In propulsion mode, the eight-switch converter efficiently drives the machine with the same torque capability as the conventional twelve-switch converter, while mitigating voltage fluctuations across dc-link capacitors by eliminating the need for dc-link midpoint connection. In charging mode, the configuration seamlessly accommodates both ac and dc charging while ensuring zero electromagnetic torque. During the ac charging mode, the eight- switch converter is controlled as an interleaved single-phase active rectifier, interfacing the single-phase ac mains through the machine windings. Whereas in dc charging mode, the converter operates as a dual two-phase interleaved dc-dc boost converter enabling the efficient power transfer from dc sources to the vehicle’s battery. The implementation of interleaving approach in both ac and dc charging modes significantly suppresses the charging current ripple. The transition between propulsion and charging modes is realized using simple hardware reconfiguration. Experimental prototyping based on a 4 kW six-phase induction machine validates the effectiveness of the proposed configuration in both propulsion and charging modes. The eight-switch converter is evaluated versus its twelve-switch and nine-switch counterparts, to assess key performance metrics such as efficiency, voltage utilization factor, and power losses.</p>