Full-Speed Range Control of a Symmetrical Six-Phase Automotive IPMSM Drive with a Cascaded DC-link Configuration

This work considers the utilization of a symmetrical six-phase interior permanent magnet synchronous machine drive, including a cascaded dc-link configuration, to make up an electric vehicle propulsion system. This way, fast charging capabilities are provided while avoiding the utilization of power semiconductors with high voltage ratings. In this scenario, the control algorithm must deal with the non-linearities of the machine, providing an accurate setpoint command for the whole torque and speed range of the drive. Therefore, cross-coupling effects between the winding sets must be considered, and the voltage of the cascaded dc-link capacitors must be actively monitored and balanced. In view of this, the authors propose a novel control approach that provides all these functionalities. The proposal is experimentally validated in a full-scale 70 kW electric drive prototype, tested in a laboratory set-up and in an electric vehicle under real driving cycle conditions.