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The Cauer ladder network (CLN) method provides an efficient representation of eddy-current fields. This paper proposes a reformulation of the CLN method that considers expansion points using the magnetic/current vector potential. To cover a wide range of frequencies, the expansion point may be changed at a later stage of the network. Only a few stages of the ladder network are required for the eddy-current field to be reconstructed accurately around the target frequency using the expansion points. [ABSTRACT FROM AUTHOR]

In this paper, a stabilized reduced-order model based on the gappy proper orthogonal decomposition (POD) technique is applied to an eddy-current problem with the non-linear material property. A classical magnetodynamic finite element formulation based on the magnetic vector potential is used as reference and starting point to build up the reduced models. The computational complexity of the non-linear problem might be reduced by the discrete empirical interpolation method-POD technique, but the eddy current effects may make this method unstable. In this paper, we propose an approach which is similar to the gappy method to successfully overcome this instability problem, while keeping the computational cost (time and memory) low. [ABSTRACT FROM AUTHOR]

This paper deals with the harmonic-balance (HB) finite-element (FE) analysis of a multi-turn winding device coupled to electrical circuits comprising nonlinear components. The eddy-current effects in the windings are accounted for via a frequency-dependent reluctivity and impedance determined with a homogenization technique. The proposed multi-frequency approach is validated through a single-phase four-diode rectifier with an axisymmetric FE model of an inductor. The system of nonlinear algebraic equations is solved by means of the Newton–Raphson method. The HB results are validated with classical time-stepping simulations. The computational cost is briefly discussed. [ABSTRACT FROM AUTHOR]

Electrical machines with stranded random windings often suffer from considerable circulating current losses. These losses have been poorly studied because of the difficulty and computational cost of modeling stranded windings, and the stochastic nature of the problem due to the uncertain positions of the strands. This paper proposes two methods to model random stranded windings of arbitrary complexity. First, a circuit model considering the entire main flux path is presented, and some practical implementation considerations are discussed. Second, a computationally efficient finite-element approach based on non-conforming meshing is presented. Finally, a method is proposed to model the random packing process of strands within a slot, without any remeshing or inductance recalculation required. The proposed methods are then compared with special no-rotor measurement data of a large number of high-speed induction machines, and good agreement is observed. [ABSTRACT FROM PUBLISHER]

This paper presents the generation of equivalent circuits from a finite-element (FE) model of electromagnetic devices using proper orthogonal decomposition (POD). This method effectively computes the frequency response of the reduced FE model constructed by the POD-based model order reduction. Then, the circuit parameters are determined so as to minimize the error between the frequency responses of the reduced FE model and equivalent circuit. The frequency characteristics of an inductor and the induction heating machine evaluated by the equivalent circuit are shown to be in good agreement with those computed from the original FE model. [ABSTRACT FROM AUTHOR]

This paper proposes an equivalent-circuit generation from the finite-element (FE) model of electromagnetic devices using a model order reduction (MOR). In this method, an equivalent circuit is directly generated from the reduced transfer function obtained using MOR based on Padé approximation via the Lanczos process. It is shown that the generated circuit yields sufficiently accurate results in both frequency and time domains. Moreover, the computational time of the present method is much shorter than that of the circuit generation based on frequency sweep using the conventional FE analysis. [ABSTRACT FROM AUTHOR]

To study a multirate system, each subsystem can be solved by a dedicated software with respect to the physical problem and the time constant. Then, the problem is the coupling of the solutions of the subsystems. The waveform relaxation method (WRM) seems to be an interesting solution for the coupling, but until now, it has been mainly applied on academic examples. In this paper, the WRM is applied to perform the coupling of a controlled rectifier and a non-linear finite element model of a transformer. [ABSTRACT FROM AUTHOR]

The Proper Orthogonal Decomposition (POD) combined with the (Discrete) Empirical Interpolation Method (DEIM) can be used to reduce the computation time of the solution of a Finite Element (FE) model. However, it can lead to numerical instabilities. To increase the robustness, the POD_DEIM model must be constructed by preserving the structure of the full FE model. In this paper, the structure preserving is applied for different potential formulations used to solve electromagnetic problems. [ABSTRACT FROM AUTHOR]

The multi-slice method allows approximation of the 3-D phenomena without carrying out a full 3-D analysis, e.g., in skewed radial flux electrical machines. The idea is to divide a 3-D machine into several 2-D finite-element models along the axis, connected by electrical circuits. Here we show how the multi-slice method is perfect for parallel computation; the computation efficiency is close to that of 2-D models in modern parallel hardware. The results are shown to agree with 3-D computation and experimental results. [ABSTRACT FROM AUTHOR]

A volume integral formulation using facet elements to compute eddy currents in thin conductive shells is presented. The formulation is general and considers the field variation through the depth due to the skin effect. The formulation leads to an equivalent lumped elements circuit that can be coupled with an external circuit. The resolution of the circuit is achieved by the independent loops method. The formulation has been validated because of two numerical examples. Results are compared with an axisymmetric finite-element method (FEM) and another shell formulation implemented in a 3-D FEM. [ABSTRACT FROM PUBLISHER]

A consistent and computationally efficient finite-element model for the simulation of the steady-state operation of surface-mounted permanent magnet brushless dc motors driven from quasi-square wave inverters is presented. The methodology combines the magnetostatic finite-element and the steady-state time-periodic circuit models with time averaging. A weak field-circuit coupling is established through the effective constant current and lumped parameters estimated at various loading conditions. The performance characteristics, determined via the proposed model for two different motors, are comparable with those obtained from the comprehensive time-stepping finite-element model, with the execution time being approximately a hundred times shorter for the former. [ABSTRACT FROM AUTHOR]