Yuhang Yuan’s research while affiliated with Southwest Jiaotong University and other places

The geometric parameters of the Null-Flux coil (NFC) are crucial to the load capacity and economic viability of electrodynamic suspension (EDS) systems. This study investigates the influence of NFC geometry on the electromagnetic force characteristics in EDS systems. Through the electromagnetic modeling of EDS mechanisms, an analytical model for EDS systems is established. Systematic experiments compare electromagnetic forces under varying NFC lengths and gaps, supported by a self-developed stationary EDS dynamic simulation platform. The results demonstrate that the average levitation force is positively correlated with the coil length, and it is larger when the coil length is close to its width. Meanwhile, the NFC length has a significant impact on the lift-to-drag ratio, while the NFC gap has a relatively smaller effect on it. This work provides a complete methodology integrating analytical modeling and experimental validation, offering practical guidelines for NFC design in maglev actuators. The findings advance EDS system optimization through quantifiable geometric criteria, particularly for transportation applications requiring precision electromagnetic force control.

High-temperature superconducting (HTS) pinning maglev has the advantages of self-stationarity, low noise and resistance. This technology can be applied in urban rail transit, such as straddle-type monorail vehicles. Due to the limited space for placing the drive device above the track, electrodynamic wheel (EDW) drive can be applied effectively utilizing the ample space on both sides of the track, realizing contactless drive. In this paper, the lateral dynamic performance of an HTS pinning maglev vehicle driven by EDW is analyzed. Initially, 2-D transient simulations under various rotational speeds of the EDW are conducted. The influence of different working air gaps on the device's normal force and propulsion force is analyzed. Subsequently, a dynamic model of HTS pinning maglev vehicle with EDW is established. EDW's influence on the lateral dynamic performance of HTS pinning maglev vehicle is analyzed, and the lateral dynamic performance of the vehicle at various speeds is simulated. The results show that the HTS pinning maglev vehicle driven by EDW has good lateral dynamic performance in the low and medium speed range, and EDW can effectively improve the lateral stationarity of HTS pinning maglev vehicle. This study can provide a new driving mode for HTS pinning maglev vehicle and reference for improving and optimizing the existing medium and low speed straddle-type monorail vehicles with HTS maglev technology.

High-temperature superconducting (HTS) pinning maglev has attracted attention due to its advantages of stable levitation without external energy, and integration of levitation and guidance. As one of the main excitation sources of the HTS pinning maglev system, permanent magnet guideway (PMG) irregularity is affected by the geometric and magnetism of PMG together. Therefore, the measurement method only for geometry in wheel-rail system no longer meets the measurement requirements of PMG irregularity. In addition, the current research on HTS pinning maglev trains is mainly based on the test line, which has certain requirements for repeated measurement and measurement convenience. In this paper, various sensors are set on a single Dewar HTS pinning maglev system. PMG magnetic induction intensity signal, the vibration response signal, and the geometric signal are measured respectively. The equidistant track marker on the PMG surface is used as keyphasor pulse signal to realize the spatial resample method. After converting the time domain signal to the spatial domain, the PMG local irregularity evaluation is carried out. Based on the 7-parameter fitting model, the PMG irregularity spectrum is fitted. Taking the Chinese mainline railway track spectrum as the contrast, it can be concluded that the mid-wave irregularity of the HTS pinning maglev system is higher. The research content of this paper provides a theoretical basis for the selection of measurement methods under different measurement requirements and conditions. The obtained irregularity power spectrum can provide a reference for the dynamic simulation of HTS pinning maglev.

High-temperature superconducting (HTS) magnetic levitation (maglev) trains for designed high speed need a non-contact braking method that can produce stable and sufficient braking forces to ensure the safety of the train during emergency braking. In order to study the braking effects of permanent magnet eddy current braking (PMECB) used in HTS maglev vehicles and its effects on the levitation performance of HTS maglev vehicles, an equivalent two-dimensional simulation model of PMECB for a HTS maglev test vehicle under different working air gaps of 5 mm, 10 mm, 15 mm and 20 mm was established in Maxwell software. Then, a 6 degree of freedom dynamic model of the vehicle was established in Universal Mechanism software. In the dynamic simulation, the normal force of PMECB was not considered, and only the detent force of PMECB was taken as the excitation of the vehicle. The simulation results show that PMECBs can reduce the vehicle to relatively low speed in a few seconds. During the operation of PMECBs, the levitation height and levitation force of the maglev Dewar will be affected, and maximum variations in levitation heights and levitation forces occur on the Dewars at both ends of the vehicle. These help us to understand the braking and levitation performance of HTS maglev vehicles under the action of PMECBs and enrich the design idea of braking and levitation systems of HTS maglev vehicles equipped with PMECBs.

High temperature superconducting (HTS) maglev, which uses the magnetic flux pinning effect to realize the levitation and operation, has attracted wide attention in the field of transportation due to its advantages of high efficiency, energy saving, safety and comfort. As the connection components between the bogie and vehicle body, and the transmission components of tractive and brake force, traction rods not only satisfy the relative motion between vehicle body and the bogie, but withstand the pounding of bogie relative to body as well. There is a great need to research the influence of traction rod parameters to HTS vehicle on its dynamic performance, which can prolong the life of the traction transmission device and enhance the running stability of vehicles. In this paper, a vehicle-bridge coupled dynamics model, considering different traction device arrangements, is established by means of multibody dynamics software Universal Mechanism (UM). And the influence of the traction transmission devices on the vehicle's dynamic performance is analyzed. The analysis results provide a reference for designing and optimizing the parameter of traction drive transmission devices.

High-temperature superconducting (HTS) magnetic levitation (maglev) has the advantages of low-energy consumption and environment-friendly. This article tried to apply this novel technology into sightseeing vehicles. As the bogie is one of the most important components of the vehicle, a new type of bogie was designed for the need of small-radius curve passing and its dynamic characteristics were evaluated. A 3D model of a bogie with primary suspension was built. By which, the space utilization of the vehicle can be improved and the passengers will have higher comfort. Then, a dynamic model of the vehicle-bridge coupled system was constructed based on a multi-body dynamics software, Universal Mechanism (UM). The dynamic performance of bogie with and without primary suspension were compared to explore its necessity. The vehicle-bridge dynamic performance was simulated and analyzed under different speeds and curve radii. The results show that the HTS maglev sightseeing vehicle with the bogie with primary suspension has favorable dynamic performance. For higher speeds and smaller curve radius, the vibration response will worsen. This study can provide references for the design and optimization of HTS maglev bogies suitable for small radius curve passing.

A new HTS maglev vehicle called KENYON that can carry 8 passengers was successfully developed in December 2019. The vehicle adopted the bogie structure of independent running gear, which brings the improvement of curve passing performance. In order to further optimize vehicle curve passing performance in view of the small radius curve of the ring test line, corresponding experimental research was carried out in this paper. The experimental results show that the small wheelbase and centripetal arrangement were beneficial to improve the vehicle's curve passing ability.