Conference Agenda

This paper presents an equivalent model for mechanical motions based on Cauer ladder circuit. It is important for electro-mechanical coupling systems to evaluate their performance as well as their control systems. For such cases, small-scaled equivalent models so called 1-D models are often used. When constructing 1-D models, if mechanical model can be constructed as circuit model, one can integrally evaluate all the systems including control systems. For this reason, mechanical motion models are constructed using an extended Cauer ladder circuit model.

Permanent magnet (PM) motors are favored in high-speed electric traction applications due to their increased efficiency and robustness based on excitation provided by brushless rotor configurations. However, in cases of dielectric oil spray cooling enabling power density increase, the accurate representation of the important interaction, amongst the electromagnetic (EM), thermal and fluid dynamics phenomena developed, necessitates complex and computationally expensive directly coupled modeling procedures. The present work introduces a particular methodology, achieving enough precision in this class of problems while involving modest computational means. The proposed method is based on indirect coupling combining 2D finite element analysis (FEA) for EM phenomena representation with 3D distributed lumped parameter thermal network (LPTN) techniques for transient thermal phenomena simulation and computational fluid dynamic (CFD) evaluations through 3D FEA for the cooling provided by the dielectric oil spray injection on the winding end zones. To that respect appropriate time varying local heat transfer coefficients (HTCs) are determined on the hairpin conductor stator non-overlapping end winding parts reflecting the heat transfers due to the oil spray. The accuracy of the proposed methodology has been checked by comparing the results to the ones of a directly coupled 3D FEA model.

High quality meshes play a crucial role in accurately capturing complex field distribution details, enhancing computational efficiency, and reducing numerical errors at the same time. However, for specialized structures such as AFPM machines, efficient and rapid mesh generation methods remain to be exploited. By noticing the layered or axially piecewise uniform geometric characteristics of typical AFPM structures, this paper proposes a multi-subdomain layered mesh generation method that combines piecewisely layered meshes with non-conforming elements at the interface of each uniform subdomain. This method allows independent meshing for each subdomain and reduces the usual pure unstructured 3D tetrahedral meshing process to several piecewise 2D meshing with simple additional extrusion. The non-matching meshes at subdomain interfaces are handled with the interpolation technique in order to impose the continuity condition for the working variables. Numerical cases are provided to validate the feasibility of the proposed method, effectively optimizing the AFPM solving process.

In recent years, single-phase permanent magnet reluctance motors (PMRMs) have attracted much attention in industry, aerospace and other fields, due to their advantages such as low cost, simple structure and the introduction of permanent magnets to enhance torque density. However, the torque pulsation, electromagnetic vibration and noise problems associated with the double salient structure are generally regarded as the major drawbacks of this type of motor. In this paper, the electromagnetic vibration characteristics of single-phase PMRMs with different topologies are comparatively investigated. The radial force models of different rotor structures are analyzed, and the coupling mechanism between radial force and vibration of single-phase PMRMs is explored through the establishment of a multi-physical field coupling model. Vibration experiments of prototypes with different rotor structures under different working conditions are conducted to verify the theoretical analysis.

Press-pack insulated gate bipolar transistors (PP IGBTs) are gradually becoming the core power conversion components of flexible DC transmission technology due to the advantages of double-sided heat dissipation, short circuit failure, and easy series connection. The reliability of PP IGBT devices is closely related to the interaction mechanisms of multiple physical fields within the PP IGBT. Therefore, this paper starts from semiconductor theory, combined with the piezoresistive effect, to build a multi-physical field coupling model of the PP IGBT. It analyzes the microscopic carrier motion characteristics inside the PP IGBT chip and the external macroscopic electromagnetic parameters under the effects of pressure and temperature, as well as the correlation between them. The study aims to reveal the mechanisms and patterns of how the changes in carrier motion inside the IGBT chip, under the coupling of temperature and pressure, affect the external electromagnetic parameters.

This paper explores the application of Parallel-in-Time (PinT) algorithm for transient semiconductor device simulations. We used the Multigrid Reduction in Time (MGRIT) algorithm to address the inefficiencies of conventional sequential time-stepping methods. Experiments on the mixed-mode device-circuit co-simulation of a 2D PiN diode’s forward and reverse recovery processes demonstrate gains in computational speed and scalability through temporal parallelism across multiple cores, highlighting the potential of PinT algorithm in semiconductor device simulations. Limitations of the PinT algorithm and potential improvements are also discussed.

Eddy current dampers utilize electromagnetic forces generated by eddy currents in a conductor moving through a magnetic field. This design eliminates mechanical contact, offering durability and long service life. However, the damping performance is typically lower than that of rubber, oil, or friction dampers. Moreover, high-conductivity materials exacerbate the skin effect, leading to increased magnetic stiffness and reduced damping efficiency. This study investigates these challenges by analyzing the performance of eddy current dampers using materials with different electrical conductivities. The evaluations were conducted under room temperature and cryogenic conditions using two-dimensional finite element analysis. The results highlight the influence of electrical conductivity and temperature on damping performance and magnetic stiffness.

Proper orthogonal decomposition is a widely used method for model order reduction, offering an efficient means to simplify complex systems. However, it has certain limitations, particularly in handling nonlinear problems and its reliance on fixed time-step computations in the time domain, which can be computationally inefficient. This paper presents an enhanced model order reduction approach based on proper orthogonal decomposition, incorporating adaptive time-stepping to address these challenges. The proposed method corrects the time step size using truncation error, the degree of nonlinearity is considered in updating step size to improve convergence. To validate the approach, a converter transformer is used as a case study, demonstrating the effectiveness of the adaptive time-stepping model in evaluating the insulation state under polarity reversal conditions.

The finite element method is commonly used to simulate transverse flux induction heating for moving strips. However, the presence of moving parts inevitably leads to mesh deformation or mesh reconstruction, significantly increasing computational effort. In this paper, a magnetothermal coupling finite element calculation method for transverse flux induction heating based on the Eulerian approach is proposed. This method allows for the simulation of transverse flux induction heating in moving strips without requiring mesh reconstruction. Furthermore, bidirectional coupling between the magnetic and thermal fields is incorporated into the calculation process to enhance accuracy. The accuracy and efficiency of the proposed method are validated using a diamond-shaped coil transverse magnetic flux induction heating model, and the results are further verified through experimental data.

This paper proposes a semi-analytical algorithm to study electromagnetic vibrations in racetrack-shaped wound cores. The algorithm incorporates elliptical approximation for analytical simplifications while accounting for the asymmetric magnetostrictive properties of silicon steel. Compared to finite element methods, this approach achieves faster computation and enhanced accuracy. The study explores deformation states, magnetostrictive performance, and magnetic field distribution within the core. Experimental results using a laser vibrometer validate the displacement calculations, showing consistency with theoretical predictions. This work contributes a novel and efficient computational method for analyzing magnetostrictive vibration phenomena in anode saturable reactors (ASR), a key component in high-voltage direct current (HVDC) systems.

Precise and swift computation of the transient electromagnetic field and temperature elevation during fault conditions of GIL is essential for optimizing design and ensuring the safe operation. However, utilizing full-scale 3D finite element methods for calculating the full-scale transient electromagnetic field of GIL is impractical due to the immense computational resources and time required. The equivalent circuit method, while highly efficient, lacks the ability to intuitively depict the transient field distribution and accurately calculate ohmic loss for coupling transient thermal-fluid field computations. This paper introduces a lightweight 2D multi-slice electromagnetic field-circuit coupling model to compute the transient electromagnetic field and ohmic loss within GIL. This approach enables the transient analysis of GIL devices spanning up to tens of kilometers to be practically feasible, improving efficiency in optimization design, and providing a fast and convenient means to improve operational safety and reliability.

This paper presents a comparative analysis of 2D and 3D modeling of transient arc discharges along guided copper rails, evaluating their capabilities and limitations. The 2D approach is shown to offer practical insights and efficiency, making it valuable for preliminary studies, though it exhibits certain deviations from the detailed representations achieved with 3D simulations. The study aims to highlight how far 2D simulations can approximate transient arc behavior under varying conditions. Results are benchmarked against experimental data and extended to assess the validity of 2D approximations across a range of scenarios. By exploring the trade-offs between computational cost and accuracy, this work advances the methodology for modeling transient arcs and provides guidance for selecting appropriate simulation strategies.