This paper has presented an innovative permanent-magnet motor with movable stators. The flux density distribution and flux lines vary with movable stator positions, thereby varying the motor torque based on movable stator positions. The analytical model of movable stators has been established and validated by using the ANSYS Maxwell software. 2-D numerical results are generated and compared with analytical results. The torque of permanent-magnet motors can be varied by moving the movable stators, according to both numerical and analytical results. Concerning motor torque variation capability achieved in this study, according to Figure 15, the ratio of the largest vs. the smallest torque is calculated as 53/23 = 2.3. In comparison, the 1st, 2nd, and 3rd gear ratios of traditional transmission in gasoline sedans such as VW Golf are 3.9, 3.45, and 1.9, respectively. Although the traditional transmission in gasoline sedans still has advantages in torque ratios, the weight and volume of transmissions increase fuel consumption of gasoline sedans. By contrast, the permanent magnet motor with movable stators proposed in this study is effective and promising in direct drive systems.

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