Electromagnetic Characteristics and Preliminary Design of Ultra-High-Speed PMSLMs

The permanent magnet synchronous linear motor (PMSLM) is a key technology for the ultra-high-speed acceleration in maglev transport systems over short distances. It has attracted significant research interest owing to its high power density, high efficiency, and excellent control performance. Nevertheless, the design of such motors faces several challenges. These include the accurate calculation of inductance parameters and the achievement of high thrust force density. To overcome these issues, this study first derives analytical expressions for per-unit-length inductance and thrust force. Based on these, key electromagnetic parameters and structural parameters of the motor are designed. A segmented design scheme is also proposed. A finite element model of a bilateral long-stator PMSLM is then established using Ansys Maxwell. Simulations are performed to analyze the motor’s back electromotive force (EMF), electromagnetic thrust force, inductance distribution, and induced voltage. The results show a good agreement between the simulation and theory. The error in inductance calculations ranges from −5.5% to +6.65%. The absolute error between the calculated and simulated thrust force values is below 0.8 kN. Furthermore, the non-uniformity in inductance distribution and the causes of thrust force fluctuation are investigated. Odd-order harmonics, such as the third and fifth, are identified in the induced voltage. This research offers a design methodology and simulation verification for ultra-high-speed PMSLMs. It lays a foundation for the future development of end-effect compensation and harmonic suppression strategies.