Electromagnetic Vibration Reduction of a Magnetic Induction Modulated Permanent Magnet Synchronous Linear Motor

Normal electromagnetic force waves are a primary source of electromagnetic vibration of permanent magnet synchronous linear motors (PMSLMs). In this paper, a magnetic induction modulated PMSLM utilizing a composite mover to reduce normal electromagnetic force fluctuation and thrust fluctuation, thereby improving vibration characteristics, is proposed. First, the normal force wave characteristics of PMSLMs are theoretically analyzed to identify the dominant vibration frequencies. Subsequently, the electromagnetic performance of the proposed PMSLM is evaluated. The results reveal that, compared with conventional PMSLMs with a single silicon steel mover core, the proposed design effectively reduces thrust fluctuation and normal force variation without compromising thrust output. Additionally, the spatiotemporal harmonic characteristics of normal force waves of both PMSLMs are compared. Based on the modal superposition method, two multi-physics finite element analysis (FEA) models are established to investigate their vibration characteristics. The analysis indicates that the vibration acceleration of the magnetic induction modulated PMSLM is reduced by up to 84% near its natural frequency, which is validated by the experiment. Finally, an eccentric semicircular slot structure is proposed to mitigate vibration distribution imbalance and further reduce the motor vibration acceleration.