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Objective Targeting the inapplicability of conventional train positioning technologies to HTS (high-temperature superconducting) maglev trains, as well as the limitations of existing positioning technologies for such trains, a method based on RFID (radio frequency identification) technology for monitoring train position is proposed. Method The RFID positioning technology is introduced, and a theoretical error model for this technology in system application are proposed. The positioning software and hardware systems are designed and constructed. To improve positioning accuracy of the system, the influence of train operating speed, reader response time, and reader-tag distance on positioning errors are analyzed. On this basis, an experimental platform is established in consideration of the specific operating environment of HTS maglev trains, and the feasibility of the proposed RFID positioning method is verified. Result & Conclusion The designed RFID-based positioning method for HTS maglev trains can achieve relatively high precision positioning of maglev trains running on circular test tracks. The proposed RFID system exhibits advantages such as high reliability, low cost, and easy maintenance.

As the main merits, self-stabilization and no magnetic resistance make the high-temperature superconducting (HTS) magnetic levitation technology a crucial area for high-speed magnetic levitation development. To guarantee a stable operation of superconducting magnetic levitation systems, the dynamic characteristics of superconducting bulk materials occupy a significant place. However, in the previous research, there is still a lack of a simulation method that can describe 6 degree of freedom (DOF) motion of the superconductor. In this paper, an electromagnetic–thermal–dynamic coupling calculation model was established first. Then, the damping characteristics of 5-DOF superconducting levitation were experimentally tested, and the response analysis of the superconductor under 1–20 Hz excitation was carried out to explore the coupled motion relationship between the various degrees of freedom of the superconductor. In addition to the above, the operating conditions and primary resonance intervals that should be avoided by the HTS maglev system were identified. Additionally, a numerical simulation was conducted to investigate the dynamic response of the HTS maglev system under impact loads. All in all, this study explored the temperature rise conditions of superconducting bulk materials under excitation force through magnetic-thermal-force multi-physics coupling research. This 6-DOF model can provide a comprehensive simulation method for superconducting maglev systems in superconductor's motion behavior, attitude, and thermal state monitoring. [ABSTRACT FROM AUTHOR]

When a YBaCuO bulk superconductor (SC) is subdivided, its levitation force may not be significantly reduced after this partitioning process. The force will decrease even less if the sectional surface introduced by partitioning is parallel to the induced current loop. Moreover, the levitation force can be maintained because the partitioning makes the SC more magnetizable. These findings have implications for longitudinal maglev technology. A method for calculating levitation forces in nonuniform fields based on critical-state theory is proposed. In this method, an SC is divided into several regions where the external field is approximately uniform within each subvolume. To minimize the force degradation introduced by partitioning, the cutting surfaces should be parallel to the induced current. This approximate approach can effectively reproduce the experiment and improve the calculation accuracy. Another application of combining and recovering discrete SCs is demonstrated, and it is shown that a recombined SC according to the small-loss partitioning condition can achieve 68% of the levitation capacity of an intact sample. In addition, the invisible cracks inside the bulk sample can be predicted by comparing its levitation force with that of the intact sample. [ABSTRACT FROM AUTHOR]

In this work, a novel levitation magnet with damping coil is proposed to address the existing issues and improve reliability. The fault mechanism of the existing magnet is analyzed and validated using a coupling model combined with inductive voltage experiments. The magnetic yoke with damping coils is designed and the equivalent magnetic circuit (EMC) model of the magnet is established. The nonlinearity of magnetic materials and the magnetic flux fluctuation due to the tooth-slot effect are considered in the EMC model. Simultaneously, the transient finite element (FEM) model is built. The magnetic flux of yoke, the inductive current of the damping coil, and the magnetic force are analyzed. A good agreement is found between EMC and FEM. Additionally, the static magnetic force is tested on the magnet test platform to validate EMC and FEM models. Results reveal that compared with the existing magnet, the magnetic flux fluctuation with damping coils is significantly reduced, and the inductive voltages with the damping coil are significantly decreased. The novel magnet with damping coils featuring excellent magnetic characteristics is more advantageous for the system's security and durability. [ABSTRACT FROM AUTHOR]