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1. Examination of the Stiffness Terms needed to Model the Dynamics of an Eddy Current based Maglev Vehicle

   https://doi.org/10.1109/TMAG.2023.3287512  

   Bruce, Colton; Bird, Jonathan (October 2023, IEEE transactions on magnetics)

   This paper re-examines the basis for each eddy current stiffness term computed from prior published steady-state eddy current models. The paper corrects prior analysis work by confirming, through the use of 2-D and 3-D dynamic finite element analysis modelling, that when a magnetic source is moving over an infinite-wide and infinite-long conductive sheet guideway the steady-state lateral and translational stiffness terms will be zero and only the vertical coupled stiffness terms need to be modelled. Using these observations, a much simplified 6 degrees-of-freedom (DoF) linearized eddy current dynamic force model can be used to compute the steady-state force changes in eddy current based maglev vehicles when operating over a wide uniform conductive track. 

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2. Analytic Damping and Stiffness Analysis for a 4-DOF Electrodynamic Wheel Maglev Vehicle

   https://doi.org/10.1109/ICELMACH.2018.8506767  

   Wright, J.; Bird, J. Z. (September 2018, 2018 XIII International Conference on Electrical Machines (ICEM))

   This paper analyzes the damping and stiffness terms of a 4-degree of freedom laboratory scale electrodynamic wheel magnetic levitation vehicle. The vehicle creates both suspension and propulsion forces through the simultaneous rotation and translation of the electrodynamic wheels above a conductive non-magnetic plate of finite thickness. The stiffness and damping terms were derived using an analytic 3-D steady-state eddy current model, and are analyzed based on their suitability for a linear state-space model. The implications with respect to static stability are discussed. 

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3. Eddy-Current Dynamic Model for Simultaneous Geometrical and Material Parameter Measurements of Magnetic Materials

   https://doi.org/10.1115/DSCC2018-9211  

   Hao, Bingjie; Lee, Kok-Meng; Bai, Kun (September 2018, Proceedings of the ASME 2018 Dynamic Systems and Control Conference)

   This paper presents a distributed current source (DCS) method for modeling the dynamic responses of eddy current density (ECD) induced in electrical conductors and its corresponding magnetic flux density (MFD); both nonmagnetic and weakly magnetized conductors are considered. Unlike conventional numerical methods such as finite element analysis (FEA), the DCS method, which accounts for the eddy-current and magnetization effects by means of equivalent volume and surface current-sources, derives closed-form solutions to the ECD and MFD fields in state-space representation. The model has been experimentally validated and verified by comparing results from FEA simulations with both harmonic and nonharmonic excitations. To gain physical insights to the measured MFD for simultaneous estimating the material/geometrical properties of a conductor, the static and dynamic responses to rectangular pulsed current excitations have been numerically investigated, confirming the feasibility and effectiveness of the measurement methods. 

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4. A Review of Segmented Stator and Rotor Designs in AC Electric Machines: Opportunities and Challenges

   https://doi.org/10.3390/eng6010007  

   Khoshoo, Bhuvan; Aggarwal, Anmol; Foster, Shanelle (January 2025, Eng)

   The use of segmented stator and rotor designs in AC electric machine construction offers several significant advantages, including a high-copper fill factor, increased torque density, improved field-weakening performance, simplified manufacturing processes, and enhanced mechanical strength. Additionally, segmented designs allow for the incorporation of oriented steel—either partially or fully—which exhibits excellent magnetic properties in the rolling direction, resulting in more efficient machine performance. However, lamination segmentation also introduces challenges. Parasitic air gaps between segments and an increased number of cut edges in the assembled stack can alter the magnetic properties of the machine, potentially leading to degraded performance. Furthermore, the use of oriented steel remains complex, as its highly nonlinear magnetic properties vary depending on the direction of the magnetic flux. This paper reviews the widely adopted stator and rotor segmentation techniques available in the literature, discussing their potential benefits and limitations. It also covers key aspects such as popular manufacturing approaches, the impact of segmentation on machine performance, advanced finite-element analysis (FEA) techniques for numerical modeling, and experimental methods for evaluating the performance of segmented stator and rotor constructions in AC machines. By addressing these areas, this work provides a comprehensive resource for machine designers seeking to develop AC machines with segmented stators and rotors. 

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5. A Hybrid Time-Efficient Modeling Approach for Acoustic Noise Prediction in SRMs

   https://doi.org/10.1109/ITEC51675.2021.9490075  

   Zhang, Ziyan; Jin, Zichao; Chen, Chengxiu; Yaman, Selin; Krishnamurthy, Mahesh (June 2021, 2021 IEEE Transportation Electrification Conference & Expo (ITEC), 2021)

   null (Ed.)

   This study presents a computationally cost-effective modeling approach for a switched reluctance machine (SRM) towards predicting vibration and acoustic noise. In the proposed approach, the SRM is modeled using Finite Element (FE) software for capturing magnetic snapshots from static simulations. Using an advanced field reconstruction method (FRM), these snapshots are used to develop basis functions to estimate magnetic fields under any arbitrary stator excitation and at any desired rotor position. This method includes magnetic properties of the machine and can estimate flux density at once instead of partially predicting it. The vibration model is built in FE software while the acoustic noise is predicted using the analytical method. The proposed study can significantly reduce the computational time for vibration and noise analysis with decent accuracy. Dynamic simulation by finite-element analysis (FEA) software and experimental verification have been carried out to verify the effectiveness of the proposed hybrid model. 

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