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At present, finite element method (FEM) is still the mainstream tool in a range of complex science and engineering applications, including the analysis of structures, heat, fluid, and electromagnetics. However, FEM becomes computationally very intensive when the number of physics equations grows and the mesh is refined. In this paper, we investigated the parallel computing techniques in the nonlinear magnetostatic field solution of an axisymmetrical actuator with permanent magnet by proposing a generalized black-box transmission line method (BB-TLM). A novel black-box circuit model was built to represent complex FEM element data. By means of the transmission line model, each element is isolated and then a series of parallel procedures is considered during the solution stages. The magnetic field distribution and magnetic force of the studied actuator are calculated by the proposed method and the simulation results are compared with COMSOL. Compared with the conventional N-R method, the generalized BB-TLM algorithm greatly reduces the computation time. [ABSTRACT FROM AUTHOR]

The consistency problem caused by the uncertainties in manufacturing process is a significant factor influencing the quality of electromagnetic device (EMD). The foundation of quality analysis and consistency optimization is the substantial calculation for the input-output characteristics of the product. As for EMD, the interaction of electricity, magnetism (permanent magnetism), and dynamics make the calculation quite complicated. At present, finite-element method (FEM) is a common method for calculating the output characteristics of EMD. However, FEM takes too much time for calculating, it is difficult to be applied for the quality analysis and consistency design of EMD that requires substantial calculation. In this paper, a new approach for the quality analysis and consistency design of EMD based on the approximate model has been proposed. First, the approximate model for calculating the EMD output characteristics is established on the basis of FEM simulation results. Second, using the approximate model, the quality analysis of batch products is conducted with Monte Carlo method. Finally, the optimal design for consistency is carried out with robust tolerance design method. The effectiveness of the method proposed in this paper is verified by the case study of a certain type of electromagnetic relay with permanent magnet. [ABSTRACT FROM AUTHOR]

As an analytical method with lumped parameters, the magnetic equivalent circuit method is usually constrained by its incapability of flux leakage and magnetic saturation compared with finite element (FE) method. We propose a new approach introducing compensation matrix Cm\times n to combine both methods. It requires a certain number of feature points by FE to compensate flux leakage at different positions and saturation extents at different coil currents, result precision within 5% and only second time consumed. Then, the approach is applied in dynamic modeling, design refinement, and performance optimization, where repetitive calculation of electromagnetic character is needed, and the results indicate the feasibility of the approach. [ABSTRACT FROM AUTHOR]

• Dynamic characteristics testing and evaluation of electromagnetic devices. • A digital modeling approach to evaluate dynamic characterization is proposed. • Multiphysics modeling approach for FEM description of the electromagnetic devices. • The nonlinear effects of temperature on the dynamic characteristics are considered. • Transmission line parallel algorithm improves the efficiency of solving FEM models. Electromagnetic systems of Electromagnetic devices involve multiphysics coupling of electromagnetic fields, electrical circuits, mechanical motion, and temperature fields. When the digital prototype model has a large number of meshes, the commercial finite element software also has the disadvantage of long computation time in the simulation of dynamic characteristics of electrical apparatus. This paper proposes a transmission line method (TLM) based digital modeling method for the electromagnetic-thermal-force coupling to test and evaluate the static and dynamic characteristics of electromagnetic devices more accurately and efficiently. The case study is developed on a direct current (DC) contactor, and the dynamic characteristics testing and modeling in the electromagnetic-thermal-force coupling of the contactor are investigated. The numerical results of the finite element method (FEM) model for the electromagnetic system of the contactor are compared with the commercial FEM software Altair Flux and the experimental results, which demonstrate the exceptional accuracy of the proposed digital modeling method for the multiphysics coupling of the DC contactor. Meanwhile, the dynamic characteristics of the DC contactor at different ambient temperatures are measured and evaluated, and the comparison with the experimental measurements shows the applicability of the proposed digital prototype model at different ambient temperatures. Compared with the conventional Newton-Raphson (NR) iteration, when dividing fine mesh and extremely fine mesh, the TLM parallel computing significantly improves the efficiency of solving the dynamic characteristics of multiphysics coupling by about 35 % and 44 % with the same computational accuracy, respectively. The dynamic characteristics evaluation method combined with digital modeling technology and experimental measurements proposed in this paper demonstrates high accuracy and solving efficiency, making a notable contribution to the field of design and optimization of electromagnetic devices. [ABSTRACT FROM AUTHOR]

The life-cycle reliability of high-power DC electromagnetic devices due to multi-source heterogeneous uncertainties in the design, manufacturing, loads, degradation and cumulative damages has become increasingly prominent, life-cycle reliability optimization has attracted extensive attention. The design optimization strategy based on reliability, which combines the static/time-independent hypothesis and random theory, is inapplicable to life-cycle design optimization. Therefore, a time-dependent uncertainty analysis and life-cycle quality reliability optimization method are proposed in this study. Based on the information entropy transformation method, the fuzzy uncertainty is transformed into a probability density function of equivalent random variables, and intervals for the random variables are determined in the standard normal space. In this way, the heterogeneous uncertainty is unified as an interval type. Moreover, the time-dependent characteristics of the uncertainty parameters are transformed into a time-dependent of the characteristics through ellipsoidal model process. A life-cycle expression method based on an orthonormal basis is proposed to form a life-cycle time-dependent non-probabilistic convex model process. Therefore, the analytical expression of out-crossing rate in which there are many non-probabilistic convex model process parameters are derived and the corresponding upper and lower bounds of out-crossing rate can be obtained. Then, a life-cycle reliability design optimization model is constructed and the optimal solution is determined from intelligence algorithm. The effectiveness of proposed method was verified by a high-power DC electromagnetic relay in renewable energy systems. [ABSTRACT FROM AUTHOR]