Control method for a magnetic-CVT motor

Traction motors of electric vehicles require wide power band characteristics and high efficiency over wide rotation speed. To achieve these requirements, we proposed a magnetic-CVT motor being composed of a magnetic-CVT gear and brushless DC motor. However, this motor has some problems. First, the efficiency of the magnetic-CVT motor is very low because of the copper loss that originates from 6 phase currents. Second, the gear ratio of the magnetic-CVT motor cannot be maintained constantly. In order to solve these problems, a new control method is proposed and its effectiveness is verified using finite element analysis.