Single-objective performance optimization of PM EDS system

In view of the optimization of the lift-to-weight ratio, lift-to-drag ratio, and suspension stiffness of the ultra-high speed permanent magnet(PM) electrodynamic suspension (EDS) system, the solution domain was divided, and boundary conditions were established. In addition, the expression of the electromagnetic force was clarified. The control variable method was adopted, five groups of independent characteristic parameters were selected, the influences of characteristic parameters on each optimization indicator were analyzed, and the optimizable variables of different optimization indicators were pointed out. The values of wavelength, thickness, and width of the permanent magnet array and the width and thickness of the induction plate were studied when the lift-to-weight ratio was the maximum under different suspension gaps. The values of wavelength of the permanent magnet array and the thickness of the induction plate were studied when the lift-to-drag ratio was the maximum under different suspension gaps. The wavelength, thickness, and width of the permanent magnet array and the thickness of the induction plate were studied when the suspension stiffness was the maximum under different suspension gaps. An experimental study of the PM EDS system was carried out, and the variation rules of electromagnetic force with the linear velocity of the permanent magnet array were obtained. Research results show that at an ultra-high speed, the lift-to-weight ratio increases significantly with the increase in the remanence of the permanent magnet array, increases monotonically with the increase in the number of permanent magnets per unit wavelength, and generally increases initially and then decreases as the wavelength and width of the permanent magnet array increase. The lift-to-weight ratio is significantly affected by the thickness of the permanent magnet array. The lift-to-drag ratio is less affected by the remanence of the permanent magnet array, the widths of the permanent magnet array and the induction plate, and the suspension gap. In addition, the lift-to-drag ratio is significantly affected by the thickness of the induction plate. Greater wavelength, thickness, and speed of the permanent magnet array are more beneficial to improve the lift-to-drag ratio. The suspension stiffness increases monotonically with the increase in the remanence, width, and thickness of the permanent magnet array, initially increases and then decreases with the increase in the wavelength of the permanent magnet array, and initially increases rapidly and then slowly decreases with the increase in the thickness of the conductor plate. The suspension stiffness changes significantly with the increase in the suspension gap and changes little with speed. By taking the lift-to-weight ratio as the optimization indicator, when the suspension gap increases from 0.012 m to 0.020 m, the optimal thickness and wavelength of the permanent magnet array and the width of the induction plate gradually increase, while the optimal width of the permanent magnet array gradually decreases. The optimal lift-to-weight ratio drops by about 50.00%. By taking the lift-to-drag ratio as the optimization indicator, when the wavelength of the permanent magnet array increases from 0.050 m to 0.500 m, the optimal thickness of the induction plate gradually increases, and the optimal lift-to-drag ratio triples approximately. By taking the suspension stiffness as the optimization indicator, when the suspension gap increases from 0.012 m to 0.020 m, the optimal wavelength of the permanent magnet array gradually increases, and the optimal width of the permanent magnet array is equal to the width of the induction plate. Furthermore, the optimal thickness of the induction plate is around 0.001 m, and the optimal suspension stiffness decreases by approximately 50.00%. Through experiments, the changing trend of electromagnetic forces at linear speeds of 0-50.00 m·s^-1 is consistent with the theoretical calculation and simulation results. The lift force first increases rapidly with the increase in speed and then gradually becomes stable. The detent force increases sharply with the increase in speed, reaches the maximum value when the linear speed is about 4.00 m·s^-1, and then decreases slowly. 3 tabs, 19 figs, 30 refs.