The magnetostriction of electrical steel is one the main sources causing deformation and vibration in rotational machine transformer cores. presence dc bias or higher harmonics magnetic field apparatus cores makes noise more serious. Therefore, it necessary to identify how different magnetization patterns contribute noise. This paper performs measurement magnetostrictive strain non-oriented grain-oriented sheets under sinusoidal excitation, with a other third harmonic component,...

In addition to the excitation condition, magnetic properties of electrical steel sheet (ESS) also depend on stress and temperature. This article proposes one systematic measurement method measuring vector (VMPs) ESS. proposed method, coupling effect temperature are considered. The uniform field distribution is generated in area specimen using a vertical-type orthogonal double-U shaped yoke. Since cross shaped, mechanical can be applied conveniently. B-probe double compound H-coil adopted...

In the early design stage of an electromagnetic device, sufficient information on uncertainties variables is not available. Therefore, a reliable optimal cannot be achieved by conventional reliability analysis, in which probabilistic method applied. This paper, considering insufficient uncertainty data, proposes possibility-based algorithm to get robust and devices. The suggested adopts possibility analysis utilizing fuzzy set theory. addition, mitigate expensive performance during...

For electromagnetic devices, there exist many uncertainty sources during design stage, performance simulation, components manufacturing and assembling. These uncertainties may deteriorate the practical operation of electrical machines from designed one or result in violation constraint conditions to a certain extent. To improve robust permanent magnet synchronous machine (PMSM), should be taken into account its whole life cycle. manage stage machines, this paper makes some explorations...

With the change of temperature, magnetic characteristics electrical steel sheet (ESS) exhibit remarkable variations, in particular, at high-temperature region. If field electromagnetic devices operating under high temperature is analyzed by magnetization data recorded room analysis findings appear to be quite different from real ones. In order understand and apply behavior ESS, a temperature-dependent hysteresis model necessary. this paper, physical background-based Jiles-Atherton (J-A)...

An accurate estimation for the magnetostrictive effect in an electrical steel sheet is helpful determining deformation and noise originating from magnetostriction during design stages of electric devices. Because limited measurement conditions, rotational modeling has been left aside calculations core deformations. In this paper, dynamic hysteresis properties under different elliptic magnetization loci a grain-oriented are investigated based on magnetic tester. A model proposed, which...

Power transformers play an important role in the safe and reliable operation of whole power grid. Once a fault occurs, it will endanger normal transformer, even result grid accidents. Accurate practical methods transformer monitoring type identification have attracted extensive attention field electrical engineering. However, is difficult to obtain large number measurement data for different types on transformer. The vibroacoustic characteristics faults significant asymmetry. For service,...

In this paper, one multi-objective robust optimization algorithm is applied to the optimal design of switched reluctance motor. The performance robustness against uncertainty in variables evaluated utilizing first order sensitivity assisted-worst case scenario approximation. reduce computing cost required by finite element analysis, Kriging surrogate model used predict motor during process. With help particle warm algorithm, a set designs are obtained through making balance between...

Purpose We examined whether the relations between home literacy environment (HLE), children's independent reading, and emergent reading skills are confounded by parents' (a genetic proxy).

Air friction loss of rotor surface for a high speed machine is quite large and difficult to be determined accurately. In this paper, the permanent magnet with rated 60000rpm was studied theoretically experimentally. The losses different speeds were calculated based on 3D finite element analysis fluid field. experimental obtained by separation tested total speeds. are accorded results which show validity feasibility calculation method loss.

This paper presents a systematical optimal design method for powder aligning fixture during forming process and magnetizing an anisotropic-bonded NdFeB magnet. Before the process, mixture ratio of magnet resin, molding tool temperature, filling density are selected to improve magnetic performance. During newly multiobjective optimization model is proposed obtain required orientation maximum field. Thus, in with high residual flux obtained by applying single-objective process. To accurately...

To extend the reliability-based optimal design to engineering electromagnetic problems, essential prerequisite is develop a numerically efficient method of reliability calculation. From practical point view, this study presents comparative on different algorithms analysis. For analysis author proposed one sensitivity-assisted Monte Carlo simulation (SA-MCS) in previous research. seek higher accuracy analysis, study, second-order derivatives are incorporated into SA-MCS method. About...

Purpose – The purpose of this paper is to propose a multi-objective optimization algorithm, which can improve both the performance robustness and constraint feasibility when uncertainty in design variables considered. Design/methodology/approach Multi-objective robust by gradient index combined with reliability-based (RBDO). Findings It shown that searching for optimal TEAM problem 22, minimize magnetic stray field keeping target system energy (180 MJ) superconductivity (quenching...

In this paper, the dynamic magnetostriction of electrical steel sheet is measured by a triaxial strain gauge based on single-sheet tester under alternating magnetic flux condition. The anisotropic property analyzed, and

The accurate estimation of the core loss is significant for optimal design power electronic transformer. This paper proposes an eddy-current formula solid ferrite with a rectangular cross-sectional area which widely employed as high-frequency transformer core, and induces variable coefficient into excess calculation. parameters in model under non-sinusoidal voltage excitation are identified based on experimental tester. proposed verified results show it feasible to apply this

A hysteresis model, based on the enhanced neural network with parallel strategy, is put forward for prediction of accurate magnetic behavior electrical steel sheets (ESSs). Aimed at overcoming drawbacks such as low convergence rate and convenient to trap into local optimum in conventional back-propagation (BPNN), a novel collaborative BPNN learning algorithm introduced according error back propagation mechanism particle swarm optimization (PSO). The reasonable selection test point set by...

A method for evaluating the equivalent permeability of soft magnetic composites (SMCs) is presented. First, a new microstructural characterization model SMCs proposed, which introduces concepts pores and gaps. The effect these two structures on properties analyzed, an analytical derived from parameters. Second, compaction process numerically simulated by discrete element (DEM) powder particle 3-D reconstruction technique. microstructure models under different conditions are established....

A method is proposed in this paper to study the effect of particle size distribution on eddy-current loss from microstructure model soft magnetic composite (SMC). Unlike previous ones, microstructural constructed based simulation data powder densification process. The process uses discrete element (DEM), and construction completed by 3D reconstruction program. generated analyzed finite (FEM) investigate differences between SMCs with multiple distributions. analysis separates into...

In this paper, in order to calculate noise and vibration resulted by transformer accurately, the multiphysics coupling analysis based on COMSOL is applied a 1000kVA oil-immersed distribution transformer. Firstly, through magnetic field with external circuit, of flux density core obtained. Secondly, taking as excitation structure field, acceleration analyzed. Thirdly, acoustic can obtain distribution. Finally, validate numerical analysis, physical experiment carried out under no-load...

The vibration and noise are serious problems for large oil-immersed power transformers, which directly affect the performance stability of transformers. no-load current, as excitation source, is very important accurate calculation noise. This paper provides a novel approach based on new field-circuit coupling model to calculate current For one 110 kV transformer, multi-physics problem including magnetic field, structural force field acoustic under alternating analyzed. Following calculation,...