Research on mathematical modeling of the servo valve torque motor considering the variation of working air-gaps leakage flux

In the current research of the magnetic circuit model of the servo valve torque motor, the magnetic flux leaking from working air-gaps is regarded as constant. However, the working air-gaps leakage flux varies with the armature rotation angle, which affects the accuracy of the existing mathematical model of the torque motor. To solve this problem, a new mathematical model of the torque motor with two working air-gaps is built. First, different from the previous model, the variation of the working air-gaps leakage flux is considered in the magnetic circuit model. A more detailed mathematical model of the torque motor is established based on the magnetic circuit model. Second, the finite element method is used to reveal that there is a linear relationship between working air-gaps leakage flux and armature rotation angle in a certain range of rotation angles. Then, the new model is validated by numerical calculation, which indicates that the theoretical results calculated by this new model show better agreement with the simulation results compared to the previous model when the armature rotation angle increases. Further, the theoretical results of the electromagnetic torque constant and magnetic spring stiffness acquired by the new model and the previous model are compared. The comparison shows that the variation of the working air-gaps leakage flux has the greatest influence on the magnetic spring stiffness. Finally, the experiments on the torque motor are conducted to verify the accuracy of the new model. The theoretical results obtained by this new model are better consistent with the experimental results than that obtained by the previous model. This study shows that considering the variation of working air-gaps leakage flux is valuable to improve the accuracy of the magnetic circuit model of the torque motor, which provides an effective guidance for the structural optimization and performance prediction of the torque motor.

Low-temperature induction heating of flat metal objects in a traveling electromagnetic field

The article discusses possible options for a low-temperature induction heating system (LTIHS) of flat metal products in a traveling electromagnetic field. The problem of calculating eddy currents, active and reactive powers induced in a heated flat object, as well as electromagnetic forces acting on the object moving it in a given direction, is posed and solved. A mathematical model has been developed that takes into account the dependence of the influence on the main parameters of the electromagnetic field of the following factors: geometric dimensions of the air gap between the poles of the magnetic circuit and the heated flat body; the longitudinal edge effect caused by the open circuit of the magnetic circuit of the inductor, as well as the transverse edge effect associated with the appearance of the longitudinal components of eddy currents in a heated flat object. The solution of particular problems of LTIHS in one- and two-dimensional formulation allows them to be simplified and to perform calculations for various design variants of induction heating devices with a traveling electromagnetic field, using a one-dimensional model that explicitly takes into account the features of electromagnetic processes in the systems under study.

Two Entangled Electrons How to Link to Each Other?—What’s the Magnetic Force State on Both Sides?

There discovered the maximum possible magnetic induction in nature, equal to the magnetic induction at the poles of an electron’s spin, When the spin magnetic moments of two electrons are close to each other, they act on each other with the maximum possible magnetic induction, and finally entered the maximally entangled state after the energy drops. By this time, the spin magnetic moments on both sides situated in anti-parallel, between them there existed four invisible magnetic circuit, and each magnetic circuit just contain a fluxon. No matter how far the distance between the spins, owing to the inalienability of fluxon, no magnetic flux leakage (coupling degree 100%), so these four magnetic circuit will always existed, maintaining the maximally entangled state system immutably. This is the material basis for the entangled state to be existed, nothing to do with “spooky action at a distance”. In this paper, a visual schematic diagram has drawn to describe these, and the magnetic force state, force relationship and “light barrier” problem are analyzed.

Suppression of Cross-Coupling Effect of Hybrid Permanent Magnet Synchronous Motor with Parallel Magnetic Circuit

Hybrid permanent magnet synchronous motor (HPMSM) has attracted increased attention in recent years due to its adjustable air gap flux. However, as a result of the cross-coupling effect of high- and low-coercive permanent magnets, the precise magnetic adjustment of HPMSM has become increasingly difficult. In order to weaken the cross-coupling effect, two methods of adding magnetic barrier and exciting coil are adopted in this paper. First, the equivalent magnetic circuit model is established, and the theoretical rationality of the weakening method is analyzed. Second, the electromagnetic performance of two weakening methods are analyzed based on the finite element analysis. Finally, the rationality of the theoretical analysis is verified, which provides the structure basis for the precise magnetic adjustment of the hybrid permanent magnet motor.

Method of parametric analysis of reciprocating electric generators with permanent magnets

A method for the parametric analysis of electric generators of reciprocating motion with permanent magnets has been developed, which allows revealing the values of the parameters of the magnetic circuit (cross-sectional area) and the working winding (number of turns) at a given value of the efficiency, providing a minimum specific gravity of the generator. The method of parametric analysis of electric generators of reciprocating motion with permanent magnets consists of three stages. The first and second stages are the electromagnetic calculation of the generator: at the first stage, the main geometric dimensions of the magnetic system and the parameters of the working winding of the generator are determined; at the second stage, the verification of the electromagnetic calculation of the generator, calculation of the nominal mode, calculation of the efficiency and assessment of the thermal state of the generator are fulfilled. At the third stage, a parametric analysis of electric generators of reciprocating motion with permanent magnets with specified constraints is carried out, as well as the refinement of the geometric dimensions and configuration of the magnetic system of the generator using a two-dimensional finite element model of the magnetic field. As a result, to ensure better use of the electrical steel of the magnetic circuit of the generator and thereby reduce its mass, the most saturated areas and areas, which are characterized by low values of the magnetic field strength, are determined. Distinctive features of the proposed technique are: the use of a minimum specific gravity of electric generators of reciprocating motion with longitudinal, transverse or combined changes in the magnetic flux passing through the working winding as an objective function; combined approach to electromagnetic calculation; taking into account the influence of the operating temperature on the parameters of the permanent magnet, as well as overheating of individual parts of the generator.

The irony of the magnet system for Kibble balances - a review

The magnet system is an essential component of the Kibble balance, a device that is used to realize the unit of mass. It is the source of the magnetic flux, and its importance is captured in the geometric factor $Bl$. Ironically, the $Bl$ factor cancels out and does not appear in the final Kibble equation. Nevertheless, care must be taken to design and build the magnet system because the cancellation is perfect only if the $Bl$ is the same in both modes: the weighing and velocity mode. This review provides the knowledge necessary to build a magnetic circuit for the Kibble balance. In addition, this article discusses the design considerations, parameter optimizations, practical adjustments to the finished product, and an assessment of systematic uncertainties associated with the magnet system.

The Analytical Comparative Analysis of Electromagnetic Characteristics of Four Typical Radial Flux Permanent Magnet Eddy Current Couplers

The analytical model of a permanent magnet eddy current coupler (PMECC) is mainly used for evaluation of its characteristics and the initial optimization of design. Based on the equivalent magnetic circuit method, this paper carries out analytical modeling for four typical PMECCs composed of surface-mounted and interior permanent magnet, slotted and non-slotted conductor rotors, which provides a theoretical basis for the subsequent research in this paper. The basic electromagnetic characteristics of the PMECCs are investigated by the established analytical model. Simultaneously, the analytical results about permeance, flux density, torque and power are verified by FEA simulation. The analysis results show that the slotted CR will obtain a much higher power density, and the iron loss mainly exists in the CRs. In addition, the analytical and FEA results agree well, which proves the reliability of the proposed, nearly unified analytical model.

Design Optimization of Secondary Element of Single-Sided Linear Induction Motors Using a Genetic Algorithm

The article focuses on the use of genetic algorithms for the design of linear induction motors. Comparison of genetic algorithm with classical methods in the context of electrical machines designing has been carried out. The results of solving an optimization problem for two designs are presented, viz. a laboratory linear induction electric motor based on a three-phase SL-5-100 inductor and a traction single-sided linear induction electric motor of an urban transport system. The optimality criterion included maximizing the power factor and efficiency, as well as the rigidity of the mechanical characteristic while ensuring a starting traction force of at least a set value. The results of optimization of such parameters of the secondary element as the width and thickness of the conductive strip as well as the thickness of the magnetic circuit are described. The relevance of the problem of optimizing the parameters of the secondary element with unchanged parameters of the inductor is due to the fact that the same inductor can be used to build various structures, while the secondary element is created for each specific application and integrated directly into the working body of the mechanism or is a driven product. To calculate the traction and energy characteristics of linear induction electric motors, an electromagnetic model based on detailed equivalent circuits was used, taking into account longitudinal and transverse edge effects and providing a calculation time for one set of parameters of about 1 s. In accordance with this model, the electric motor is reduced to a set of three detailed equivalent circuits: a magnetic circuit, primary and secondary electrical circuits. The result of the optimization of these electric motors was an increase in the efficiency by 1.6 and 1.4 %, respectively, an increase in the power factor by 0.9 and 0.2 %, and an increase in the rigidity of traction characteristics and starting traction force.

DEVELOPMENT OF VIBRATION ISOLATOR USING MAGNETORHEOLOGICAL ELASTOMER MATERIAL BASED

Many vibration isolators, for instance, passive vehicle mounting device, have fixed stiffness. This article presents the development of the adjustable stiffness engine mounting magnetorheological elastomers (MREs) based to reduce vibration. The development of MREs vibration isolator is to design of engine mounting first step, for next step is to simulate the electromagnetic circuit. The housing material selection and MREs thickness were considered to equip sufficient, uniform magnetic fields to change the stiffness. The innovative magnetic circuit design includes the type and size of the wire and the number of the coil turns to obtain the best magnetic fields to eliminate vibration. Finite Element Method Magnetics (FEMM) software was utilized to show the effectiveness of the electromagnetic circuit in generating magnetic fields through the MREs. Finally, various current input influence to the MREs vibration isolator is investigated. The higher current input is more useful to eliminate vibration using MREs isolator system.

Estimation of the domestic materials application possibility in the active part of a high-speed electric generator for micro-GTP

The article discusses the possibility of using domestic materials in a high-speed electric generator. The features of Japanese electrical steel 20NTN1500 and domestic-made electrical steel grades 2420 and 2421 for the stator magnetic circuit are shown. The features of American steel AISI 455 and structural steel grades Steel 40, Steel 40H, Steel 45 are considered in the case of a rotor. A feature of the use of structural steels in the design of the high-speed electric generator rotor for micro-gas turbine plants is the need for precise observance of the rotor heat treatment mode after its manufacture, control of the dimensions and quality of surface treatment.