A novel high-torque-density and wide-speed-range hub motor for electric vehicle propulsion

This article proposes a novel hub motor, which uses variable electromagnetic (EM) gearing to leverage torque and rotation speed when necessary. Depending on driving conditions, the motor can select a high EM gear ratio or a low EM gear ratio to either increase torque or to increase speed. The technology requires combination of a pole-changeable phase winding and geometry-variable stator profile. The performance of the motor is evaluated and compared with other traditional motors.