Theory and optimum design of PM Vernier motor

The paper introduces a novel motor, known as the PM Vernier motor, which produce high torques at very low speed and can be used for direct drive applications. After a description of its construction and principle of high torque generation at very low speed, a design method is shown which can optimize the motor torque. The torque measured for a motor made on an experimental basis showed a high torque per rotor unit volume of 112 kNm/m/sup 3/ from a current of 8 A and agreed well with calculated values. A block diagram of a speed control scheme and an example of measured speed response characteristics are also shown.