Parametric model of electric machines based on exponential Fourier approximations of magnetic air gap flux density and inductance

2018 ◽  
Vol 37 (1) ◽  
pp. 520-535 ◽  
Author(s):  
Norman Borchardt ◽  
Roland Kasper
Keyword(s):  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Fourier Coefficients ◽  
Magnetic Circuit ◽  
Parametric Model ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Electrical Machine ◽  
Content Type

Purpose This study aims to present a parametric model of a novel electrical machine, based on a slotless air gap winding, allowing for fast and precise magnetic circuit calculations. Design/methodology/approach Approximations of Fourier coefficients through an exponential function deliver the required nonlinear air gap flux density and inductance. Accordingly, major machine characteristics, such as back-EMF and torque, can be calculated analytically with high speed and precision. A physical model of the electrical machine with air gap windings is given. It is based on a finite element analysis of the air gap magnetic flux density and inductance. The air gap height and the permanent magnetic height are considered as magnetic circuit parameters. Findings In total, 11 Fourier coefficient matrixes with 65 sampling points each were generated. From each, matrix a two-dimensional surface function was approximated by using exponentials. Optimal parameters were calculated by the least-squares method. Comparison with the finite element model demonstrates a very low error of the analytical approximation for all Fourier coefficients considered. Finally, the dynamics of an electrical machine, modeled using the preceding magnetic flux density approximation, are analyzed in MATLAB Simulink. Required approximations of the phase self-inductance and mutual inductance were given. Accordingly, the effects of the two magnetic circuit parameters on the dynamics of electrical machine current as well as the electrical machine torque are explained. Originality/value The presented model offers high accuracy comparable to FE-models, needing only very limited computational complexity.

Magnetic Field Finite Element Analysis of Generator with Rotor Inter-Turn Short-Circuit Fault

2014 ◽  
Vol 707 ◽  
pp. 343-347
Author(s):  
Yong Gang Li ◽  
Bing Han
Keyword(s):  
Magnetic Field ◽  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Early Stage ◽  
Short Circuit ◽  
Air Gap ◽  
Operating Conditions ◽  
Magnetic Flux Density ◽  
Short Circuit Fault

Rotor inter-turn short-circuit is a common fault in generator and it is a research hotspot to identify the fault at its early stage. Considering the disadvantage of circuit analytical method, this paper establishes a 2D transient finite element electromagnetic-circuit coupling model, and calculates the magnetic field at normal and fault situations through the powerful post-processing function of ANSOFT, then magnetic flux density cloud pictures and air-gap magnetic flux density curves of different operating conditions are got. Using MATLAB to analyze and deal with the air-gap flux density cures, we can get the differences of faults in different levels and different positions, which provide a basis for further study of rotor inter-turn short-circuit fault.

Investigation the Performance of Axial Channel Rotor in Inset Permanent Magnet Synchronous Machine

2012 ◽  
Vol 260-261 ◽  
pp. 559-564 ◽  
Author(s):  
Jeeng Min Ling ◽  
Tajuddin Nur
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
High Efficiency ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Electrical Machine ◽  
Axial Channel ◽  
Conventional Machine ◽  
Rotor Core

An electrical machine is constructed with some holes or axial hollows in the rotor core for special purpose. The effects of axial hole in the proposed Inset Permanent Magnet Machine (Inset PMSM) with eight radial poles are analyzed by the magnetic flux density in air gap. The characteristics associated with magnetic flux density of every magnet poles in the air gap, magnetic flux losses in the rotor teeth, density magnetic flux in the rotor core surface and torque of the machine are also investigated and compared. Results show small direct reactance and less area in the proposed axial channel rotor core compared with the convention Inset PMSM. It imply to a lighter weight and high efficiency machine design. The finite element simulation shows the magnetic flux density per pole in air gap of the proposed rotor structure remain constant or may be a little bit drop compared with the conventional machine.

Influence of magnetic concentrator on Hall effect based current sensor

2018 ◽  
Vol 37 (4) ◽  
pp. 1481-1488
Author(s):  
Ivan Yatchev ◽  
Mehmet Sen ◽  
Iosko Balabozov ◽  
Ivan Kostov
Keyword(s):  
Magnetic Flux ◽  
Hall Effect ◽  
Flux Density ◽  
Output Signal ◽  
Air Gap ◽  
Current Sensor ◽  
Magnetic Flux Density ◽  
Content Type ◽  
Hall Plate ◽  
Open Core

Purpose The purpose of the paper is to clarify the influence of introducing magnetic concentrators on the performance of Hall effect based current sensors and to obtain dependencies of the sensor characteristics on the conductor position. Design/methodology/approach The finite element method and Comsol software are used for analysis of the three-dimensional magnetic field of the constructions of Hall effect based current sensor with different types of magnetic concentrators – closed-core (of rectangular and toroidal type) and open-core of toroidal type – with additional larger air gap. The Hall plate is also included in the model with its real dimensions and the magnetic flux density is obtained by integrating over its volume. Findings It has been found that there is dependence of the output signal (proportional to the magnetic flux density) of Hall effect based current sensor with both closed- and open-core magnetic concentrators on the position of the current carrying conductor. Distribution of the magnetic flux density and dependencies of its value in the Hall plate on the conductor position and on the additional air gap have been obtained. Optimization is carried out with respect to the additional air gap and cross-section dimensions of the concentrator. Originality/value Estimation of the influence of the introducing magnetic concentrators is made with respect to relationships between the output signal and conductor position for different constructions of the magnetic core of the concentrators.

Flux density calculation of air gap for switched reluctance motor considering magnetic saturation based on sub-domain method

2018 ◽  
Vol 37 (6) ◽  
pp. 2081-2092
Author(s):  
Xianhai Pang ◽  
Haijun Zhang ◽  
Shuhong Wang ◽  
Hao Jing
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Flux Density ◽  
Switched Reluctance Motor ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Magnetic Saturation ◽  
Content Type ◽  
Switched Reluctance ◽  
Reluctance Motor

Purpose The purpose of this paper is to study the saturation and nonlinear performance of magnetic field in the air gap of switched reluctance motor (SRM). Design/methodology/approach The analytical method of sub-domain combined with the saturation compensation method is used to determine the nonlinear distribution of air gap magnetic field in SRM. Also, the resolutions of the two-dimensional (2D) Laplace’s equation and Poisson’s equation in polar coordinates are used to obtain the simplified expression of magnetic flux density. Findings For verifying the effectiveness of analytical model, the results are compared with those obtained from the 2D finite element method (FEM). The influence of magnetic saturation is taken into account by associating the sub-domain analysis result with the nonlinear B-H properties of stator and rotor iron. The magnetic flux density in radial and tangential direction considering the saturation effect may be calculated accurately. It can be seen that one can easily determine the linear analytical results accurately, whereas it is difficult to determine the magnetic flux density with saturation influence; especially at some local positions, there is a larger difference between analytical and FE model due to the complex boundary conditions. Practical implications This paper presents the development and optimization design of high-performance SRM. Originality/value The magnetic saturation may be taken into account for the SRM and analytical models support to simulated system performance.

scholarly journals Design of a New 1D Halbach Magnet Array with Good Sinusoidal Magnetic Field by Analyzing the Curved Surface

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2522
Author(s):  
Guangdou Liu ◽  
Shiqin Hou ◽  
Xingping Xu ◽  
Wensheng Xiao
Keyword(s):  
Magnetic Field ◽  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnets ◽  
Air Gap ◽  
Curved Surface ◽  
Magnetic Flux Density ◽  
Sinusoidal Magnetic Field ◽  
The Magnetic Field

In the linear and planar motors, the 1D Halbach magnet array is extensively used. The sinusoidal property of the magnetic field deteriorates by analyzing the magnetic field at a small air gap. Therefore, a new 1D Halbach magnet array is proposed, in which the permanent magnet with a curved surface is applied. Based on the superposition of principle and Fourier series, the magnetic flux density distribution is derived. The optimized curved surface is obtained and fitted by a polynomial. The sinusoidal magnetic field is verified by comparing it with the magnetic flux density of the finite element model. Through the analysis of different dimensions of the permanent magnet array, the optimization result has good applicability. The force ripple can be significantly reduced by the new magnet array. The effect on the mass and air gap is investigated compared with a conventional magnet array with rectangular permanent magnets. In conclusion, the new magnet array design has the scalability to be extended to various sizes of motor and is especially suitable for small air gap applications.

scholarly journals DESIGN OF A SINGLE-PHASE RADIAL FLUX PERMANENT MAGNET GENERATOR WITH VARIATION OF THE STATOR DIAMETER

2019 ◽  
Vol 81 (4) ◽  
Author(s):  
Hari Prasetijo ◽  
Winasis Winasis ◽  
Priswanto Priswanto ◽  
Dadan Hermawan
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Single Phase ◽  
Air Gap ◽  
Wire Diameter ◽  
Terminal Phase ◽  
Magnetic Flux Density ◽  
Phase Voltage ◽  
Radial Flux

This study aims to observe the influence of the changing stator dimension on the air gap magnetic flux density (Bg) in the design of a single-phase radial flux permanent magnet generator (RFPMG). The changes in stator dimension were carried out by using three different wire diameters as stator wire, namely, AWG 14 (d = 1.63 mm), AWG 15 (d = 1.45 mm) and AWG 16 (d = 1.29 mm). The dimension of the width of the stator teeth (Wts) was fixed such that a larger stator wire diameter will require a larger stator outside diameter (Dso). By fixing the dimensions of the rotor, permanent magnet, air gap (lg) and stator inner diameter, the magnitude of the magnetic flux density in the air gap (Bg) can be determined. This flux density was used to calculate the phase back electromotive force (Eph). The terminal phase voltage (V∅) was determined after calculating the stator wire impedance (Z) with a constant current of 3.63 A. The study method was conducted by determining the design parameters, calculating the design variables, designing the generator dimensions using AutoCad and determining the magnetic flux density using FEMM simulation.  The results show that the magnetic flux density in the air gap and the phase back emf Eph slightly decrease with increasing stator dimension because of increasing reluctance. However, the voltage drop is more dominant when the stator coil wire diameter is smaller. Thus, a larger diameter of the stator wire would allow terminal phase voltage (V∅) to become slightly larger. With a stator wire diameter of 1.29, 1.45 and 1.63 mm, the impedance values of the stator wire (Z) were 9.52746, 9.23581 and 9.06421 Ω and the terminal phase voltages (V∅) were 220.73, 221.57 and 222.80 V, respectively. Increasing the power capacity (S) in the RFPMG design by increasing the diameter (d) of the stator wire will cause a significant increase in the percentage of the stator maximum current carrying capacity wire but the decrease in stator wire impedance is not significant. Thus, it will reduce the phase terminal voltage (V∅) from its nominal value.

scholarly journals Finite Element Analysis of the Magnetic Field Distribution in a Magnetic Abrasive Finishing Station and its Impact on the Effects of Finishing Stainless Steel AISI 304L

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 194
Author(s):  
Michał Marczak ◽  
Józef Zawora
Keyword(s):  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Magnetic Flux Density ◽  
Regression Equations ◽  
Element Analysis ◽  
Aisi 304L ◽  
Magnetic Abrasive Finishing ◽  
The Real ◽  
Abrasive Finishing

In this article, we present a numerical model of a magnetic abrasive finishing station, which was analyzed using the finite element method (FEM). The obtained results were compared with the real values measured on an experimental station of our own design. The prepared station had the option of adjusting the magnetic flux density inside the machining gap, the width of which could be changed from 10 to 30 mm. The maximum value of the magnetic flux density inside the air gap was 0.8 T. The real distribution of magnetic flux density in the finishing area was also analyzed. A design of experiment was carried out with the following variables: abrasive grain concentration, width of the machining gap, and process duration. The results are presented in the form of regression equations and characteristics for selected roughness parameters.

scholarly journals A Novel Excitation Approach for Power Transformer Simulation Based on Finite Element Analysis

2021 ◽  
Vol 11 (21) ◽  
pp. 10334
Author(s):  
Wen-Ching Chang ◽  
Cheng-Chien Kuo
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Magnetic Flux ◽  
Flux Density ◽  
Power Transformer ◽  
Core Loss ◽  
Power Transformers ◽  
Magnetic Flux Density ◽  
External Excitation ◽  
Element Method

Power transformers play an indispensable component in AC transmission systems. If the operating condition of a power transformer can be accurately predicted before the equipment is operated, it will help transformer manufacturers to design optimized power transformers. In the optimal design of the power transformer, the design value of the magnetic flux density in the core is important, and it affects the efficiency, cost, and life cycle. Therefore, this paper uses the software of ANSYS Maxwell to solve the instantaneous magnetic flux density distribution, core loss distribution, and total iron loss of the iron core based on the finite element method in the time domain. . In addition, a new external excitation equation is proposed. The new external excitation equation can improve the accuracy of the simulation results and reduce the simulation time. Finally, the three-phase five-limb transformer is developed, and actually measures the local magnetic flux density and total core loss to verify the feasibility of the proposed finite element method of model and simulation parameters.

scholarly journals Prediction of Inhomogeneous Stress in Metal Structures: A Hybrid Approach Combining Eddy Current Technique and Finite Element Method

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Yating Yu ◽  
Fei Yuan ◽  
Hanchao Li ◽  
Cristian Ulianov ◽  
Guiyun Tian
Keyword(s):  
Finite Element ◽  
Stress Distribution ◽  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Magnetic Flux Density ◽  
Fe Method ◽  
Metal Structures ◽  
Current Technique ◽  
The Relationship

Concentrated stresses and residual ones are critical for the metal structures’ health, because they can cause microcracks that require emergency maintenance or can result in potential accidents. Therefore, an accurate approach to the measurement of stresses is key for ensuring the health of metal structures. The eddy current technique is an effective approach to detect the stress according to the piezoresistive effect. However, it is limited to detect the surface stress due to the skin effect. In engineering, the stress distribution is inhomogeneous; therefore, to predict the inhomogeneous stress distribution, this paper proposes a nondestructive approach which combines the eddy current technique and finite element (FE) method. The experimental data achieved through the eddy current technique determines the relationship between the applied force and the magnetic flux density, while numerical simulations through the FE method bridge the relationship between the magnetic flux density and the stress distribution in different directions. Therefore, we can predict the inhomogeneous stress nondestructively. As a case study, the applied stress in a three-point-bending simply supported beam was evaluated, and the relative error is less than 8% in the whole beam. This approach can be expected to predict the residual stress in metal structures, such as rail and vehicle structures, if the stress distribution pattern is known.

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