Bulk Superconductor Levitation Devices: Advances in and Prospects for Development

High-temperature superconductor (HTS) maglev system shows a significant potential to be applied to high-speed rail transportation based on its passive stable levitation owning to the coupling between the HTS bulks and permanent magnet guideway (PMG). And as one of the key factors to guarantee the safe and stable operation of HTS maglev, the dynamic characteristics of the HTS bulks reflecting the operation performance of HTS maglev system under high-speed running conditions should be focused on. Therefore, this paper, based on H-formulation, established a finite element model of an HTS-PMG system, and assessed its feasibility by experiments. Moreover, the random free vibration of the HTS bulk caused by guideway random irregularity at high speed is also studied by this validated model. The random vibration characteristics and temperature variation of the HTS bulk at three high speeds (600 km/h, 800 km/h, and 1000 km/h) under vertical vibration, lateral vibration, and vertical-lateral coupling vibration, respectively, are compared. The results show that at high speed, vertical vibration can only cause the fluctuation of levitation height, while lateral vibration and vertical-lateral coupled vibration will affect both lateral offset and levitation height. Compared with the mere vertical or lateral vibration mode, the levitation height attenuation and temperature rise of the coupling vibration mode is greater due to more energy loss caused by magnetic flux motion, but it can be aid in the suppression of the vibration in the vertical and lateral direction. The increase of velocity intensifies the vibration strength of the HTS bulk and increases the fluctuation of the levitation height, lateral offset, and temperature rise. However, the vibration at a certain high speed causes a limited temperature rise and thus a limited influence on the bulk performance, and the HTS bulk is still in the safe operating range at a maximum speed of 1000 km/h. These conclusions are anticipated to provide some references for the future high-speed application of the HTS maglev system.

Section: Model Verificationmentioning

confidence: 99%

Vertical and lateral random vibration of high-temperature superconductor maglev under high-speed operation conditions

Huang

Ye²,

Ke³

et al. 2023

“…The experimental configuration is introduced in figure 7. The Halbach type PMG (illustrated in figure 2) and two 64 × 32 × 13 mm 3 YBCO bulks processed by ATZ GmbH [59] were utilized. The experimental process is as follows:…”

Section: Data Validationmentioning

confidence: 99%

Electromagnetic force behavior of superconducting bulks passing electromagnetic turnout

Peng,

Wang,

Zhou

et al. 2023

High temperature superconducting (HTS) Maglev is a promising technology owing to its excellent electromagnetic properties of non-control stability and frictionless. As a critical component of HTS Maglev, the turnout poses challenges due to the use of the permanent magnet guideways (PMGs) that are difficult to switch mechanically. With simple structure and rapid responsiveness, electromagnetic turnout has become an interesting research field of HTS Maglev. The electromagnetic turnout is designed to control the electromagnetic force of the HTS bulks by adjusting the magnetic field using an electromagnetic-permanent magnetic structure. However, the magnetic field generated by the combination of the electromagnet and the PMs inevitably differs from the magnetic field above the PMGs, affecting the electromagnetic force behavior of the HTS bulks. To guarantee optimal performance of the electromagnetic turnout, the variation process of the magnetic field peak (MFP) above the turnout is analyzed. Furthermore, a three-dimensional superconducting model based on the H-formulation and motion equation is built to obtain the electromagnetic force of the HTS bulks passing the turnout. It’s concluded that higher cooling heights (CHs) in the preparation and higher working heights (WHs) in the turnout area are recommended to reduce the magnetic resistance and avoid the destabilizing effect. In addition, the smaller bulks experience greater resistance, and the longer bulks are prone to nodding, while the wider bulks are prone to shaking above the turnout. Properly matching HTS bulks with operating conditions improves electromagnetic force behavior and benefits HTS Maglev turnout passability.

“…Figure 3(a) above gives a detailed schematic diagram of the whole HTS maglev vehicle and the location of onboard sensors. As shown in figure 3(a), four maglev cryostats with three-seeded YBaCuO bulks inside (each 64 × 32 × 13 mm 3 ) (from Adelwitz Technologiezentrum GmbH) were installed on the vehicle frame [22]. And figure 3(b) expressed that a lateral laser displacement sensor (Omron) was installed on the vehicle bogie in order to test the LD of the vehicle.…”

Section: Experimental Descriptionmentioning

confidence: 99%

Vertical and lateral drift behavior of a linear superconducting magnetic bearing system under multi-operating modes

Lei

Ling

Wang

et al. 2020

Since the discovery of high temperature superconducting (HTS) material, HTS maglev with the characteristics of self-stabilization and zero magnetic drag, has shown excellent potential for future transportation applications. However, this stability characteristic of HTS maglev is difficult to fully ensure in a spatial position, because of the magnetic flux flow and creep of the HTS bulk. Hence, to study the drift phenomenon of the HTS maglev vehicle excited by this unguaranteed stability characteristic, the linear superconducting magnetic bearing system, composed of a ring permanent magnetic guideway line (double track) and a HTS maglev vehicle, the 'Super-Maglev', was utilized. This system aims to explore the drift phenomenon in the vertical and lateral directions of the whole maglev vehicle under various operating conditions: different running speeds, unbalanced loading and cyclic loading situations. As an illustration induced by the experimental results, the lateral drift (LD) at a faster running speed (15 km h −1 ) is twice than that at 10 km h −1 . Also, compared to the constant load condition, the vertical drift (VD) under cyclic load is larger. Moreover, with time going by, both LD and VD tend to be stable. Specifically, for the LD curve, it can be fitted by an exponential function. Finally, all the above experimental results support references for the future design and study of linear SMB systems.