Analytical Optimization of Electrodynamic Suspension for Ultrahigh-Speed Ground Transportation

Electrodynamic suspension with a permanent magnet Halbach array is suitable for ultrahigh-speed vacuum pipeline transportation. The optimization of a Halbach array is helpful to save cost and increase carrying capacity. Intricate analytical expressions of electromagnetic forces or time-consuming numerical simulation show inherent defects in the structural optimization. To solve the abovementioned problem, this article develops an analytical optimization by two stages. First, a brief approximate analytical expression of electromagnetic forces is established by omitting high-order harmonic components for both the scalar magnetic potential and vector magnetic potential. Second, the lift-to-weight ratio is taken as the optimization index, and the optimal wavelength-to-gap ratio and thickness-to-gap ratios are put forward by seeking extreme values. The numerical simulation is conducted to verify the validation of the analytical optimization, and the result shows that the optimal structural parameters are highly reliable. An experimental rotatory device for electrodynamic suspension with optimal sizes for a Halbach array is built to verify the validation of the analytical expressions of electromagnetic forces.