Magnetic Circuit Research Articles

Design and analysis of a passive adaptive wall-climbing robot on variable curvature ship facades

To improve the adaptive motion performance of traditional wall-climbing robots on variable-curvature facades, a crawler-type wall-climbing robot suitable for ship wall features is proposed by utilizing the advantages of passive mechanisms in realizing autonomous robots. The robot consists of two passive adaptive crawler mechanisms and a connecting module. Each track structure contains multiple permanent magnets that can passively adapt to concave and convex facades of different curvatures. A static failure model is established according to the characteristics of the triangular distributed load, and the minimum adsorption force required for the robot to achieve safe motion is determined. The Halbach Array magnetic circuit design method was used to construct a gap-type permanent magnet adsorption model for lightweight design. The influence of wall thickness and air gap distance on the adsorption force is analyzed by parametric simulation. The prototype platform test shows that the robot can realize adaptive variable curvature motion through passive adjustment of the mobile mechanism attitude and has a certain load capacity.

Structure, soft magnetic properties of Fe-based magnetic composites and its practical application

A multi-stage technique for applying insulating coatings to metal powder particles has been developed in order to create a new class of Fe-based soft magnetic materials with improved characteristics. The density value calculated from the data of X-ray diffraction analysis is approximately 3 % higher than the experimentally measured values, which are 7.4–7.45 g/cm3. The low porosity of the composites is confirmed by the SEM and EDX results. The proposed method of encapsulation of iron powder with an oxide layer is a highly economical method for applying coatings of various chemical compositions to metal powders, and can be widely used in practice to obtain electrical materials. Comprehensive studies of the properties of the obtained samples of powder composite materials based on ABC100.30 iron, the particles of which are encapsulated with phosphorus oxide, have been carried out. It has been established that in a field of 1.5 T, the losses at a frequency of 1 kHz decrease 10 times with an increase in the thickness to 30 nm. The synthesized materials are recommended for use in the development of various types of high-frequency electric motors, generators, chokes, magnetic circuits and electrodes for high-frequency welding and other applications.

Magnetic circuit design for the performance experiment of shear yield stress enhanced by compression of magnetorheological fluids

The shear yield stress is an important parameter for the industrial application of magnetorheological (MR) fluids. A test equipment was designed and built to perform investigations on the behaviours of compression and shear after squeeze of MR fluids. Mathematical expression of magnetic flux density was further established. Furthermore, the magnetic field distribution of the test device based on two-coil mode and single-coil mode was simulated and compared using finite element analysis(ANSYS/Multiphysics). An experimental test system was fabricated and modified based on the final conditions and simulation results. The compression and shear after squeeze performances of MR fluids were tested. The results showed that a smaller initial gap distance or a larger compressive strain corresponds to a larger compressive stress under the same external magnetic field strength. The shear yield stress after the squeeze of MR fluids increases quickly with the increasing compression stress and the increasing magnetic flux density. This test equipment was thought to be suitable for studying the compression and shear after squeeze performances of MR fluids.

Mover structure optimization and performance improvement for halbach consequent-pole PM synchronous linear motors with flux barrier

Aiming at the problems of large thrust ripple, low thrust density and magnetic leakage in the structure of Halbach consequent-pole PM synchronous linear motor, this paper proposes a flux barrier Halbach Consequent-Pole PM Synchronous Linear Motors (BHCP-PMSLM) by using the combination of unequal height PMs and air flux barrier. Firstly, after analyzing the structural magnetic leakage by the magnetic circuit method, the new motor structure proposed by adding an air flux barrier is used to suppress the magnetic leakage and to determine the structural shape of the air flux barrier. Secondly, the GA-ELM-GA algorithm was used to optimize the structural parameters of the motor with the optimization objectives of increasing thrust and reducing thrust ripple, the optimum motor structure parameters are obtained. Then, calculation and comparison of the electromagnetic characteristics of the new structure with three conventional PM synchronous linear motors with non-salient (NS-PMSLM) and Halbach consequent-pole (HCP-PMSLM). From the comparison results, the proposed structure has advantages, so the prototype was machined and experimented. The experimental results show that the optimization algorithm is effective, and the new structure increases the PM utilization by 41.1% and 7.4%, the thrust density by 5.3% and 12.1%, and the thrust fluctuation by 21% less than HCP-PMLSM compared to the conventional non-salient poles and Halbach consequent-pole.

A high-precision TMR sensor array system for detecting surface and internal defects in thin sheet of steel

The online detection of small defects within thin steel holds significant importance in the field of steel manufacturing. This paper presents a high-precision flux leakage measurement system based on tunneling magnetoresistance sensors for detecting small defects in thin steel. We optimized the probe size and magnetic circuit design through numerical simulations and used the developed instrument to detect a standard mimicking through-hole defect plate, achieving a high signal-to-noise ratio and successfully detecting artificial defects small to a diameter of 50 μm. Additionally, we detected an actual internal defect in thin steel provided by the steel plant, meeting the required industrial accuracy. The data acquisition process in this study has been optimized to achieve real-time display and defect localization. The measurement scheme proposed in this paper has great potential for online monitoring of the thin steel production process.

Impact of GOES grade mixing on the iron losses of single-phase magnetic cores

The paper presents an analytical model to predict and analyze the specific iron losses of 1-phase magnetic cores with several grain-oriented electrical steel (GOES) grades. The analytical results are compared to experimental results obtained with a step-lap magnetic core circuit. The investigations show that the specific iron losses do not systematically vary linearly function of the proportion of each material. Analyzing the flux density distribution allows to quantify these non-linearities.

Modelling of influence of mechanical stresses arising in magnetic circuit on magnetizing characteristic

Modelling of influence of mechanical stresses arising in magnetic circuit on magnetizing characteristic

Development of a simulation model for assessing the technical condition of the magnetic circuit of oil power transformers by measuring the temperature of the tank and the external environment

In the article, the authors analyzed how oil-filled power transformers ensure reliable and stable operation of power transmission systems by providing efficient transmission of electricity of different voltages. In the article, the authors found that the main elements of oil-filled power transformers - the magnetic circuit, the coil and the technical condition of the oil - directly determine the performance of oil-filled power transformers. In this work, a simulation model was developed to evaluate the magnetic circuit of power oil transformers based on the measured temperature of the tank and the external environment during express diagnosis. A simulation model has been developed that allows to calculate the technical condition of oil power transformers operating in city power networks. It is shown that the developed model allows to calculate the value of the technical condition of the oil power transformer with the help of diagnostic parameters. In order to represent the technical state of the magnetic circuit of the oil power transformer, the functions of changing the state value of the output variable in the Mamdani fuzzy logic method are shown and the block diagrams are drawn up. Author’s using the Mamdani fuzzy logic method, express diagnosis of the technical condition of the “Magnetic core of the oil power transformer” was carried out in the Matlab simulink program. During the evaluation, the value of the output parameter is taken from 0 to 100, and each step is divided by 10, the smallest value is 0, and the largest is 100.

Research on a novel water-cooling multi-cylinder magnetorheological transmission device.

Power transmission is an important application for magnetorheological (MR) fluid, and the cylinder-type power transmission device is a novel transmission form due to its high stability, higher transmission torque, and large ratio of power to mass. This work designed a novel multi-cylinder transmission device with a water-cooling channel because the MR transmission device, especially high-power MR transmission device, inevitably works in the high-temperature environment. Based on Ohm's law and electromagnetism theory, the magnetic circuit in the novel MR transmission device is designed, and the magnetoresistance was calculated. The finite element method is used to analyze the magnetic field in the device to ensure that the magnetic field in the working gap of MR fluid is strong enough for the MR effects. The temperature of the MR fluid inside the device is analyzed by the finite element method in the natural cooling state and the water-cooling state, respectively, so as to obtain the performance of water cooling. The novel MR transmission device is manufactured to verify its power transmission capability and heat-dissipation performance. The experimental results show that the novel device can transmit a maximum torque of 70 N m, consistent with the rated torque. In addition, compared with natural cooling, the water cooling makes the temperature of the MR fluid to drop by 32.7% under the same working condition. This is the first time that the cooling channel is set up in the cylinder-type MR transmission device, which will provide a solution for the higher power transmission capacity by MR fluid.

Modeling of Coupled Electric and Magnetic Circuits in Electromagnetic Suspension Vehicles

Modeling of Coupled Electric and Magnetic Circuits in Electromagnetic Suspension Vehicles

Magnetic Circuit Number Improvement of Novel Multi-Series Magnetic Circuit Variable Flux Memory Machines with Reduced Magnetizing Current

Magnetic Circuit Number Improvement of Novel Multi-Series Magnetic Circuit Variable Flux Memory Machines with Reduced Magnetizing Current

Magnetic Decoupling: Basis to Form New Electrical Machines

Abstract Magnetic decoupling principle when applied to electrical machines states that if two windings are configured for different number of pole pairs, they would not interact with each other magnetically even though they share a common magnetic core. This principle forms the basis for developing special machines where two or more machines can be integrated with the same magnetic circuit. This paper deals with formulating the mathematical analysis that determines the validity of this principle during practical conditions (i.e. non-sinusoidal winding distribution, flux saturation, etc.). Extensive Finite Element Method (FEM) simulation results from the Ansys Maxwell-2D software platform closely obey the conclusions derived from the mathematical analysis. As an example, new brushless and magnetless synchronous machines (SMs) have been developed by using this principle. It is designed by embedding an induction machine (IM) with a SM. Experimental investigations conducted on the laboratory prototype support the mathematical analysis dealt with in this paper.

Magnetic Equivalent Circuit Model for a Two Degree-of-Freedom Rotary-Linear Machine with Transverse Flux Structure

Magnetic Equivalent Circuit Model for a Two Degree-of-Freedom Rotary-Linear Machine with Transverse Flux Structure

Analysis of Proximity Loss of Electrical Machines Using Mesh-Based Magnetic Equivalent Circuit

Analysis of Proximity Loss of Electrical Machines Using Mesh-Based Magnetic Equivalent Circuit

Distributed Magnetic Equivalent Circuit Modelling of Synchronous Machines

Distributed Magnetic Equivalent Circuit Modelling of Synchronous Machines

Control System Analysis of a Linear Rotary Motor with Single Directional Magnetic Circuit Structure

Control System Analysis of a Linear Rotary Motor with Single Directional Magnetic Circuit Structure

Complementary Series Magnetic Circuit Based Stator-Yokeless Dual Rotor PM Vernier Reluctance Machine for In-wheel Propulsion

Complementary Series Magnetic Circuit Based Stator-Yokeless Dual Rotor PM Vernier Reluctance Machine for In-wheel Propulsion

Combined Regulation Performance Research of the Novel Flux-Torque Regulation Hybrid Excitation Machine with Axial-Radial Magnetic Circuit

Combined Regulation Performance Research of the Novel Flux-Torque Regulation Hybrid Excitation Machine with Axial-Radial Magnetic Circuit

Calculation and Analysis of an Integrated Motor–MB Magnetic Circuit Model

Calculation and Analysis of an Integrated Motor–MB Magnetic Circuit Model

Potential Interpretation of the Meissner Effect in Superconductors: Insights from Vector Magnetic Circuit Theory

Potential Interpretation of the Meissner Effect in Superconductors: Insights from Vector Magnetic Circuit Theory