Radial Vibration Attenuation Caused by the Tangential Force of the Permanent Magnet Propulsion Motor Based on the Lever Effect

Low‐frequency vibration is a key performance indicator for underwater vehicles, especially in applications with strict acoustic compliance requirements. The main source of vibration in integer slot permanent magnet synchronous motors (PMSM) is various orders of electromagnetic force waves acting on the stator tooth tips. Research has shown that for surface mounted permanent magnet synchronous motors, the surface vibration of the motor casing is closely related to the tangential force acting on the stator teeth. Reducing the number of stator teeth appropriately can effectively alleviate this type of vibration. Firstly, based on the Maxwell stress tensor method, the electromagnetic force model acting on the stator teeth was derived, and the mechanism of vibration caused by tangential force was analysed. Secondly, establish a mathematical model to describe the radial vibration transmitted from the tangential force on the stator teeth to the shell through the lever effect. Then, perform finite element simulation to compare the radial and tangential vibration characteristics of motors with different numbers of teeth. The simulation results show that reducing the number of teeth can effectively reduce the surface vibration of the casing caused by tangential forces on the stator teeth while maintaining the same volume of the motor. Finally, vibration and underwater noise tests were conducted on two prototype motors of underwater vehicles with the same volume but different numbers of teeth to verify the effectiveness of this method.