It is inevitable for power transformers to suffer from multiple impacts of short-circuit (SC) current and huge dynamic electromagnetic force in service, which may cause large elastic plastic deformations. Under the SC fault, distribution flux leakage amplitude be disturbed by winding deformations or displacement. This paper analyzes cumulative strain-stress characteristics transformer windings using a coupled electromagnetic-structural analysis solution. The force, mechanical stress,...

Numerous efforts are devoted to reducing the defects at perovskite surface and/or grain boundary; however, grown-in inside is rarely studied. Here, influence of cooling rate on point concentration in polycrystalline film during heat treatment processing investigated. With combination theoretical and experimental studies, this work reveals that supersaturated films generate process its improves as increases. The can be minimized through slowing rate. As a result, optimized FAPbI

As a reliable and non-destructive technique, frequency response analysis (FRA) has been widely recognized for transformer winding deformation detection assessment. In this paper, functions (FRFs) are obtained by two different FRA measurement connection ways, namely, end-to-end voltage ratio (EE) transfer (TF) measurements. At the same time, according to sensitivities of FRFs electrical parameters equivalent circuit model investigated. Based on Tellegen theorem, adjoint network method is...

The single current sensor operation (SCSO) has attracted widespread attention in the motor drive system because of its ability to reduce cost and volume. However, when SCSO is used with conventional space vector puleswidth modulation (SVPWM) technique, reconstruction unobservable area sector boundary low will degrade accuracy sampling data. In this article, a mixed SVPWM (MSVPWM) control scheme proposed eliminate area. With scheme, zero vectors (<inline-formula><tex-math...

In this paper, the magnetic integration of resonant reset forward (RRF) converter and magnetic-thermal coupling analysis integrated (IM) components are explored. The formulas reluctance, winding turns, flux density obtained based on equivalent circuit minimum current pulsation scheme. Meanwhile, circuit-field model RRF IM built with finite-element (FEA) method. simulation results illustrate that core works in an unsaturated condition, temperature rise is about 20 °C, has almost same power...

An accurate analytical model for litz-wire (LW) winding loss calculation of power electronic transformers (PETs) was deduced. First, the skin effect and proximity losses at bundle levels a single straight LW were introduced. Then, an air-core studied by adopting coordinate transformation technique (CTT) considering helical (HW) configurations twisting (TCs). Last, 2-D windings magnetic materials, configurations, (WCs) proposed with help CTT, Dowell method, Roth's method. This is helpful...

A numerical simulation, considering the two-way interactions of electromagnetic, thermal, and fluid fields with deformation associated during a levitation melting process, is performed using finite-element method. Material properties dependent on temperature are applied for simulation. In addition, surface-to-ambient radiation phase change considered, arbitrary Lagrangian-Eulerian formulation employed to model metal sample process. The oscillations at different times also simulated....

The insufficient ability to withstand short circuit of power transformer seriously affects the safety system, so it is very necessary calculate strength windings accurately. Two-dimensional electromagnetic-structure coupling method applied mechanical properties for a 220 kV transformer. distribution stress and displacement are obtained analyzed under short-circuit fault. result reflects leakage flux density between high low voltage higher than that in other parts windings. two subjected...

Mechanical characteristics analysis of normal and defective transformer windings with eccentric distance under short-circuit (SC) fault are conducted using three-dimensional finite element method (3-D FEM). The change maximum stress displacement different distances high voltage winding obtained. It is found that the increase may cause Von Mises rises fault. But has less influence on winding, comparing windings. results can provide reference for design maintenance transformers.

Electromagnetic levitation (EML) melting process is performed by adopting the finite-element method. It a complicated field-coupled problem, which involves two-way interactions of electromagnetic, thermal, fluid flow fields as well deformation. Oscillations solid titanium metal sample are studied to obtain time for their balance positions under different electrical factors, such frequency, current, and number coils turn. Droplet size liquid titanium, might be affected also studied. shown...

A numerical modeling method is proposed for the melting process of Titanium metals alloys powder preparation used 3D printing. The simulation, which involves tight coupling between electromagnetic field, thermal field and fluid flow as well deformation associated during process, conducted by adopting finite element method. two-way strategy to include interactions these fields incorporating material properties dependent on temperature terms. In addition, heat radiation phase change are also...

Core losses of nanocrystalline alloy high frequency transformer (HFT) are calculated by adopting the finite element method with magnetic hysteresis effects considered. A normal Preisach model is used to represent during numerical simulation. The features simple formulations and easy parameters identification. dynamic circuit laminated cores for operation calculate core losses. Results compared between (FEM) prove accuracy method, it also provides a more way general compute loss cores.

The elastic characteristics of transformer winding materials have an important influence on its deformation due to short-circuit (SC) fault. This paper presents electromagnetic-thermal-fluid-mechanical coupling analysis method for dynamic deformat

Abstract The organic room temperature phosphorescence (RTP) materials via host–guest doped method receive considerable attention in the fields of optoelectronics, bioimaging, and information encryption. Despite many with excellent RTP properties have been developed, their luminous mechanism is still limited. Here, a series materials, using benzophenone as host quinone compounds guests, were constructed to investigate effect triplet energy gap (Δ E T ) between guest on states population....

In the title compound, C8H10N2O2, which is a derivative of benzonitrile, there are an intra­molecular N—H⋯O hydrogen bond and inter­molecular O—H⋯N bonds.

The dynamic characteristics of transformer windings under short circuit state are great significance to the safe operation transformers. electromagnetic properties a 220 kV transformer, including leakage magnetic field and force windings, calculated using finite element method (FEM). During circuit, power windings' force, displacement stress calculated. motion process because big analyzed. analysis research results can provide reference for taking measures enhance ability withstand windings.

This paper studies a novel iterative detection algorithm for data in orthogonal frequency division multiplexing systems the presence of phase noise (PHN) and channel estimation errors. By simplifying maximum posteriori based on theory variational inference, an optimization problem over free energy is formulated. After that, data, PHN state information obtained jointly iteratively. The simulations indicate validity this show better performance compared with traditional schemes.

Purpose The purpose of this paper is to implement the macro-modeling and passivity enforcement for equivalent high frequency circuit model a single-phase winding an alternating current (AC) three-phase motor. It provides stable strictly passive Foster-type macro-model winding. Consequently, network guaranteed when it connected with external circuit. validated on permanent magnet synchronous Furthermore, corresponding windings could be obtained accordingly. Design/methodology/approach...