The mutual inductance is the core parameter of electrodynamic suspension (EDS) as it couples the onboard coils and ground coils to realize the stable suspension. The precise and efficient calculation of mutual inductance is therefore of great significance to understand and optimize the characteristics of EDS train, which has achieved a manned speed in excess of 600 km/h. In this article, we proposed a calculation method of mutual inductance, considering the geometrical details of coils and the attitude of bogie, by means of the 3-D discretization of coils and the spatial coordinate transformation of discrete units. Based on this methodology, the analytical model was established, and the dependence of computation time and precision on the discretization degree is intensively discussed. Afterward, the finite-element analysis (FEA) was adopted to check the accuracy and effectiveness of the proposed methodology. Compared with FEA, the computation time has been reduced by 97% with accuracy reserved. Finally, a testing platform was constructed to further verify the availability of the proposed model. In summary, the proposed methodology can realize efficient calculation of mutual inductance in consideration of more realistic situations, providing an invaluable tool for the complex studies of superconducting EDS train.

Artificial neural network (ANN) has recently been considered in weighting factors (WFs) optimization for finite control-set model predictive control (FCS-MPC). However, the training of the traditional ANN is complicated and the predictive accuracy is limited by gradient vanishing. For this motivation, this paper proposes a WFs optimization method based on an aggregated residual network (ResNet) which combines the advantages of residual connection and aggregated transformation. Specifically, the residual connection avoids the gradient vanishing of ANN while the aggregated transformation simplifies the training procedure. Furthermore, the input layer of the designed network incorporates the parameters and working conditions of permanent magnet synchronous motor (PMSM). Consequently, the proposed method is capable of precisely predicting the optimal WFs to enhance the performance of FCS-MPC under various operating conditions. Comparative studies are conducted to highlight the training and generalization ability of the aggregated ResNet. Finally, the feasibility and the dynamic adjustment of the predicted WFs are experimentally validated through a platform of PMSM drives fed by three-level neutral-point-clamped inverter.

In this article, we propose a novel analytical-experiment coupling method to characterize the electromagnetic forces of superconducting electrodynamic suspension system. The basic idea of this method is that, the induced currents of the ground null-flux coils (NFCs) are predicted by analytical calculation, but the electromagnetic forces on the onboard superconducting magnets are directly measured. To ensure the calculation accuracy of induced current, a Neumann's formula-based analytical model was derived and its accuracy was confirmed by comparing with the finite-element model and the existing analytical model, which is based on the harmonic approximation. The prominent merit of this method is that it is free of high speed rotating motion and thus, has no limitations of testing speed. We further made a proof-of-principle experimental setup, which consists of a coated-superconductor magnet and a few NFCs, to check the effectiveness of the proposed method. By this setup, the dependence of electromagnetic forces, i.e., levitation force, guidance force, and drag force, were measured as a function of displacement and speed. It was found that, results obtained by the proposed method are in agreement with 3-D finite-element simulation, which to some extent validatesthe proposed method.

Transverse flux machines (TFMs) can achieve high force density by the reducing the pole pitch because of the decoupling of electric and magnetic loadings. But the main flux linkage interlinking with the armature coils will decrease as the pole pitch reducing, resulting in motor performance degradation. Unlike the approaches adopted by many literatures to suppress the leakage flux, this paper proposes a novel dual-consequent-pole transverse flux linear machine by adopting dual-PM structure. Without increasing the occupied volume, the coil flux linkage is enhanced and the force density can be further improved. At first, the basic configuration and operation principle are introduced at first. Then the leading parameter influence on the force density are investigated. The electromagnetic performance of the proposed machine is investigated by three-dimensional finite element analysis and is compared with its counterparts. The field distribution, winding flux linkage, back EMF, detent force and thrust force are emphasized as well as the efficiency and power factor. Finally, a prototype machine is constructed and tested to validate the theoretical analysis.

Superconducting electrodynamic suspension (EDS) as one of the most promising ultrahigh-speed transportations has been widely followed with great interest in the past decades, and service safety under high-speed operation is always the focus of academic attention. Thereinto, an evaluation method of quench behavior can effectively reduce and even avoid the risky accident in advance for the EDS train, possessing in a more realistic sense. In this article, we established an analytical model for the superconducting EDS with cross-connection, fully considering the arbitrary attitudes of the bogie and closed-loop operation of onboard superconducting magnets (SCMs), on the basis of spatial coordinate transformation and dynamic circuit theory. Meanwhile, the data of the finite-element model and experiment, regarded as references, validate the availability of the proposed analytical model. Afterward, we systematically analyzed and revealed the end effect caused by the SCMs and characteristics of 3-D electromagnetic interactions from the perspective of normal operation and quench conditions, respectively. The results show that the quench behaviors of SCMs have a significant influence on the operating characteristics of trains and are dependent upon the installation position of the disabled SCMs, providing an invaluable tool for the studies of the train dynamics under quench conditions.

In this paper, a novel dual-consequent-pole transverse flux motor and its analytical model are proposed. Differ from existed transverse flux machines, the proposed motor owns core-tooth-to-magnet types of consequent-pole configuration on both stator and rotor. This unique motor configuration improves the no-load permanent magnet flux linkage interlinking with armature winding, thus leading to an enhanced torque density. The structure and working principle of the proposed motor are introduced as the first half part. Then, based on the combination of equivalent magnetic circuit method and subdomain method, an analytical modeling method is proposed to estimate the electromagnetic performance of the proposed motor. The parameters of the equivalent magnetic circuit model, e.g., the magnetomotive forces and reluctances are calculated based on subdomain model technique, considering the influence of the cores' saturation and the axial end effect during calculation. Based on the magnetic field distribution result, the electromagnetic performance is estimated. The analytical results are verified by both finite element method and prototype experiment.