A permanent magnet motor with reversible salient poles

In order to reduce energy consumption, we have developed a technique that quickly reverses salient poles in permanent magnet (PM) motors. When this proposed technique is used, because of this permanent magnetization, PM motors can change negative salient poles to positive salient poles. This paper proposes a novel PM motor that uses our proposed technique to reverse saliency and describes the principle of reversible pole saliency as well as the motor characteristics that are caused by reversible saliency. When the proposed motor operates with negative salient poles, a higher torque is produced at low speeds; when the motor reverses to positive salient poles, higher power and efficiency are produced at high speeds. These results confirm that the proposed motor can reverse the saliency direction of the pole and that the reversible salient pole allows the motor to have high torque at low speeds and high power at high speeds as well as to operate over a wide range of speeds.