Research on mechanism of eddy current in rail of maglev and optimum design of electromagnet

Aim: Due to the movement of medium-low speed maglev vehicles, eddy current is generated in the rail, leading to reduced levitation force. This detrimental effect becomes more prominent with increasing velocity. In order to reduce the influence of eddy current effect, the electromagnet is optimized to meet the requirement of vehicle speeding up from 100km/h to 160km/h. Methods: To maintain a constant levitation force, the current must also increase accordingly resulting in higher power consumption and heat generation. In this paper, a mathematical model is established by analytical method, focusing on the mechanism and influencing factors of eddy current. Three-dimensional transient magnetic field magnet model is analyzed by the ANSYS electromagnetic simulation software Maxwell. Results: The levitation force is related to five parameters, such as speed, length of the electromagnet, rail height, rail thickness and air gap. According to the finite element simulation results, when the train speed is 160 km/h, the levitation force of the end electromagnet is reduced by about 21.9 %. The levitation force of optimized electromagnet increases by 27 % under the same current, which can compensate for the drop of levitation force caused by eddy current .The levitation force is 41.4 kN at the speed of 160 km/h, which is slightly larger than the 39.6 kN of the former electromagnet static levitation force, which can meet the requirements. Conclusion: The result confirms that optimization methods proposed above are valid and effective.