Influence of movement direction on levitation performance and energy dissipation in a superconducting maglev system

Abstract

During the regular operation of a maglev system, the superconducting levitation body may move away from the working position due to the external disturbance and the curved part of the guideway. Based on the A − V formulation of magnetoquasistatic Maxwell’s equations, in this paper, a two-dimensional numerical model is applied to study the influence of movement direction on a typical maglev system consisting of an infinitely long high-temperature superconductor and a guideway of two infinitely long parallel permanent magnets with opposite horizontal magnetization. After the highly nonlinear current-voltage characteristic of the superconductor is taken into account, the levitation performance change and the energy dissipation induced by the relative movement of the superconductor and the guideway are discussed. The results show that the levitation force, guidance force and power loss are strongly dependent on the movement direction and speed of the superconductor when it moves away from the working position. If the superconductor moves periodically through the working position, these three physical quantities will change periodically with time. Interestingly, the power loss drastically increases during the first cycle, and after the first cycle it starts to decrease and finally tends to a dynamic steady state. Moreover, an increase in the tilt angle of movement direction will improve the maximum levitation force and, simultaneously, enhance the energy dissipation of the maglev system.

Dynamic simulations of actual superconducting maglev systems considering thermal and rotational effects

“…Figures 3(c) and (d) show the temperature evolution during vibration. In general, flux vortices will move in and out as the SC oscillates, resulting in the redistribution of induced currents and the energy dissipation [33]. As a consequence, the temperature profile becomes very complex in the SC.…”

“…Many experimental and theoretical works have studied the levitation force and static stability by changing the system parameters, such as, on the one hand, the dimensions, cooling process, critical current density and working point of the SC and, on the other hand, the number, size, horizontal interval and magnetization of the PMs in the guideway [23][24][25][26]. Moreover, based on Maxwell's equations, a series of formulations such as A-V, T-ω and H have been proposed to analyze the time-dependent levitation for maglev systems in two-dimensional (2D) or even 3D cases, where the SC is usually assumed to move along some virtual displacement [27][28][29][30][31][32][33]. Such displacement is not necessarily equal to the one followed by the system after a perturbation of equilibrium.…”

Fast time-varying current triggering flux jumps of multi-filamentary Nb3Sn wire exposed to oblique magnetic field

“…So, we performed simulations using other two numerical methods for comparison in order to check the validity of the implementation of the numerical model with H formulation in the commercial software package COMSOL Multiphysics [58,59]. Similar to H formulation, numerical simulations with H − f formulation [60,61] is also implemented in COMSOL Multiphysics, while we performed A − V formulation [62,63] by home-brewed code using MATLAB programming language, which does not need a very large air Figure 3. Thermomagnetic stability/instability diagram in the n − Γ plane (here, the n is U 0 /kT).…”