A Design Strategy for Vibration Reduction in a Dual-Stator PMSM Based on Combined Mechanical-Electrical Shifting

A dual-stator permanent magnet synchronous motor offers both structural and electrical redundancy, making it suitable for high-reliability applications such as urban air mobility. To address vibration issues that reduce the reliability of propulsion systems, this study proposed a combined mechanical-electrical shifting method that combines mechanical stator shifting with electrical phase adjustment of armature currents. To determine the optimum stator shift angle for effective vibration reduction, the radial air-gap electromagnetic force density (AEFD), which is the primary cause of vibration, was analytically derived from the spatial harmonics of the radial air-gap magnetic flux density. The variation in AEFD with respect to the stator shift angle and current amplitude was analyzed, and the resulting stator deformation was evaluated using finite element analysis. Experimental validation was conducted to verify the stator shift angle that resulted in the minimum deformation and to confirm the trend of deformation variation. The proposed method enables the identification of an optimum stator shift angle that reduces vibration while maintaining torque and efficiency.