An analytical approach and finite element evaluation of leakage fluxes of the PMs in a non-slotted axial flux permanent magnet machine

2018 ◽  
Vol 37 (3) ◽  
pp. 1085-1098
Author(s):  
Reza Mirzahosseini ◽  
Ahmad Darabi ◽  
Mohsen Assili
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Flux Density ◽  
Accurate Determination ◽  
Three Dimensional ◽  
Air Gap ◽  
Design Stage ◽  
Axial Flux ◽  
Content Type ◽  
Leakage Flux

Purpose Consideration of leakage fluxes in the preliminary design stage of a machine is important for accurate determination of machine dimensions and prediction of performance characteristics. This paper aims to obtain some equations for calculating the average air gap flux density, the flux density within the magnet and the air gap leakage flux factor. Design/methodology/approach A detailed magnetic equivalent circuit (MEC) is presented for a TORUS-type non-slotted axial flux permanent magnet (TORUS-NS AFPM) machine. In this MEC, the leakage flux occurring between two adjacent magnets and the leakage fluxes taking place between the magnet and rotor iron at the interpolar, inner and outer edges of the magnets are considered. According to the proposed MEC and by using flux division law, some equations are extracted. A three-dimensional finite element method (FEM) is used to evaluate the proposed analytical equations. The study machine is a 3.7 kW and 1,400 rpm TORUS-NS AFPM machine. Findings The air gap leakage flux factor, the average air gap flux density and the flux density within the magnet are calculated using the proposed equations and FEM. All the results of FEM confirm the excellent accuracy of the proposed analytical method. Originality/value The new equations presented in this paper can be applied for leakage flux evaluating purposes.

Analytical calculation of leakage permeance of coreless axial flux permanent magnet generator

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Jun Zhu ◽  
Shuaihui Li ◽  
Xiangwei Guo ◽  
Huaichun Nan ◽  
Ming Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Permanent Magnet ◽  
Magnetic Circuit ◽  
Axial Magnetic Field ◽  
Three Dimensional ◽  
Analytical Calculation ◽  
Content Type ◽  
Leakage Flux ◽  
Element Method

Purpose This paper aims to study the relationship between leakage flux coefficient and the coreless axial magnetic field permanent magnet synchronous generator (AFPMSG) size and obtain the expressions of leakage flux coefficient. Design/methodology/approach In this paper, a magnetic circuit model of coreless AFPMSG is proposed. Four kinds of leakage permeances of permanent magnet (PM) are considered, and the expression of no-load leakage flux coefficient is obtained. Solving the integral region of leakage permeances by generator size, which improves the accuracy of the solution. Findings Finite element method and magnetic circuit method are used to obtain the no-load leakage flux coefficient and its variation trend charts with the change of pole arc coefficient, air gap length and PM thickness. The average errors of the two methods are 2.835%, 0.84% and 1.347%, respectively. At the same time, the results of single-phase electromotive force obtained by magnetic circuit method, three dimensional finite element method and prototype experiments are 19.36 V, 18.82 V and 19.09 V, respectively. The results show that the magnetic circuit method is correct in calculating the no-load leakage flux coefficient. Originality/value The special structure of the coreless AFPMSG is considered in the presented equivalent magnetic circuit and equations, and the equations in this paper can be applied for leakage flux evaluating purposes and initial parameter selection of the coreless AFPMSG.

scholarly journals A novel method for modeling the air gap flux density of the axial-flux permanent magnet eddy current coupler considering the end-effect

2021 ◽  
Vol 7 ◽  
pp. 508-514
Author(s):  
Wenhui Li ◽  
Dazhi Wang ◽  
Deshan Kong ◽  
Sihan Wang ◽  
Zhong Hua
Keyword(s):  
Permanent Magnet ◽  
Flux Density ◽  
Eddy Current ◽  
Air Gap ◽  
End Effect ◽  
Axial Flux ◽  
Novel Method

A Nonlinear Magnetic Circuit Analysis of a Permanent Magnet Biased Homopolar Bearing

1999 ◽  
Author(s):  
Andrew Kenny ◽  
Alan Palazzolo
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Magnet ◽  
Analytical Methods ◽  
Magnetic Circuit ◽  
Three Dimensional ◽  
Magnetic Bearing ◽  
Axial Flux ◽  
Element Analysis ◽  
Good Agreement

Abstract A magnetic circuit model for a homopolar magnetic bearing is presented. This model connects the fore and aft circumferential flux paths with axial flux paths through the rotor and back iron. The bias flux is provided by a circumferential permanent magnet in the back iron. Results for an analysis using the nonlinear Hyperco50 B-H curve are presented. These results are compared to the results of a three dimensional magnetostatic finite element analysis. The two analytical methods are in good agreement and show that the control flux in this type of bearing follows both circumferential and axial paths.

scholarly journals A Novel Axial-Flux Dual-Stator Toothless Permanent Magnet Machine for Flywheel Energy Storage

Symmetry ◽  
2022 ◽  
Vol 14 (1) ◽  
pp. 61
Author(s):  
Yong Zhao ◽  
Fangzhou Lu ◽  
Changxin Fan ◽  
Jufeng Yang
Keyword(s):  
Energy Storage ◽  
Permanent Magnet ◽  
Flux Density ◽  
Load Capacity ◽  
Core Loss ◽  
Torque Ripple ◽  
Air Gap ◽  
Flywheel Energy Storage ◽  
Axial Flux ◽  
Permanent Magnet Machine

This paper presents an alternative system called the axial-flux dual-stator toothless permanent magnet machine (AFDSTPMM) system for flywheel energy storage. This system lowers self-dissipation by producing less core loss than existing structures; a permanent magnet (PM) array is put forward to enhance the air–gap flux density of the symmetrical air gap on both sides. Moreover, its vertical stability is strengthened through the adoption of an axial-flux machine, so expensive active magnetic bearings can be replaced. The symmetry configuration of the AFDSTPMM system is shown in this paper. Then, several parts of the AFDSTPMM system are optimized thoroughly, including stator windings, number of pole pairs and the PM parameters. Further, the performance of the proposed PM array, including back-EMFs, air–gap flux density, average torque, torque ripple and over-load capacity, are compared with the Halbach PM array and spoke PM array, showing the superiority of proposed configuration. Finally, 3D simulations were made to testify for the 2D analyses.

The Analysis of Air Gap Flux Density in Permanent Magnet Brushless Motor with External Rotor

2011 ◽  
Vol 383-390 ◽  
pp. 2666-2671
Author(s):  
Rui Yuan Xu ◽  
Cun Shan Zhang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Density Distribution ◽  
Permanent Magnet ◽  
Flux Density ◽  
Load Condition ◽  
Air Gap ◽  
Brushless Motor ◽  
Flux Density Distribution ◽  
External Rotor

The air gap flux density distribution in different radius of three conditions such as stator iron without slotting, stator iron slotting under no load condition and stator iron slotting under load condition is discussed using the 2-D finite element method. The effect of slotting on the distribution of air gap flux density of permanent magnet brushless motor is also analyzed.

Design and analysis of an axial flux permanent magnet motor for the direct drive radial piston pump

2019 ◽  
Vol 233 (19-20) ◽  
pp. 7077-7088
Author(s):  
Jingxiang Li ◽  
Xingwang Meng ◽  
Peng Dong ◽  
Shengdun Zhao
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Three Dimensional ◽  
Piston Pump ◽  
Direct Drive ◽  
Axial Flux ◽  
Drive Motor ◽  
Dimensional Finite Element ◽  
New Type ◽  
Three Dimensional Finite Element

Direct drive motor-pumps have attracted a lot of attention from researchers because of high efficiency and compact structure. This paper presents a new type of direct drive motor-pump, which integrates the structure of the radial piston pump and axial-flux permanent-magnet machine. The rotor of the disc motor is fixedly connected to the pump rotor, and the new pump uses a new type of distribution shaft for oil distribution. This structure reduces the intermediate transmission mechanism, and the application of the disc motor further reduces the axial size, the overall volume, and heat dissipation. The efficiency of the entire system has been improved. The three-dimensional finite element method is used to dynamically analyze flow field in the flow channel, which is extracted and simplified. The flow and pressure of the pump meet the design requirements in the simulation. A disc motor was designed for the pump, and the theoretical formula of the disc motor was derived. The initial size of the motor was obtained. The response surface method and three-dimensional finite element are used to optimize the corresponding axial-flux permanent-magnet machine. Loading the torque condition of the pump to the load end of the motor, the response of the motor meets the requirements.

scholarly journals Analysis and Optimization of Axial Flux Permanent Magnet Machine for Cogging Torque Reduction

Mathematics ◽  
2021 ◽  
Vol 9 (15) ◽  
pp. 1738
Author(s):  
Hina Usman ◽  
Junaid Ikram ◽  
Khurram Saleem Alimgeer ◽  
Muhammad Yousuf ◽  
Syed Sabir Hussain Bukhari ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Three Dimensional ◽  
Latin Hypercube Sampling ◽  
Air Gap ◽  
Axial Flux ◽  
Element Analysis ◽  
Cogging Torque ◽  
Basic Source ◽  
Three Dimensional Finite Element ◽  
Torque Ripples

In this paper, a hexagonal magnet shape is proposed to have an arc profile capable of reducing torque ripples resulting from cogging torque in a single-sided axial flux permanent magnet (AFPM) machine. The arc-shaped permanent magnet increases the air-gap length effectively and makes the flux of the air-gap more sinusoidal, which decreases air-gap flux density and hence causes a reduction in cogging torque. Cogging torque is the basic source of vibration, along with the noise in PM machines, since it is the main cause of torque ripples. Cogging torque is independent of the load current and is proportional to the air-gap flux and the reluctance variation. Three-dimensional finite element analysis (FEA) is used in the JMAG-Designer to analyze the performance of the conventional and proposed hexagonal-shaped PM AFPM machines. The proposed shape is designed to reduce cogging torque, and the voltage remains the same as compared to the conventional hexagonal-shaped PM machine. Further, optimization is performed by utilizing an asymmetric overhang. Latin hypercube sampling (LHS) is used to create samples, the kriging method is applied to approximate the model, and a genetic algorithm is applied to obtain the optimum parameters of the machine.

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.

scholarly journals Analytical Model of the Slotless Double-Sided Axial Flux Permanent-Magnet Brushless Machines

2020 ◽  
Vol 12 (1) ◽  
pp. 38-50
Author(s):  
A. Ghaffari
Keyword(s):  
Magnetic Flux ◽  
Permanent Magnet ◽  
Flux Density ◽  
Analytical Model ◽  
Design Stage ◽  
Magnetic Flux Density ◽  
Magnetic Vector Potential ◽  
Axial Flux ◽  
Internal Rotor ◽  
Analytical Approaches

Analytical approaches, if possible, are suggested for saving the simulation time in the design stage of the electrical machines. This benefit is highlighted when the optimization issues including too many iterations are desired. Hence, this paper presents a 2-D analytical model for magnetic field distribution based on the sub-domain method in a slotless double-sided axial flux permanent-magnet (PM) brushless machines (AFPMBMs) with internal-rotor-external-stators. According to this method, the machine cross-section is divided into the appropriate number of sub-regions and the related partial differential equations (PDEs) extracted from Maxwell equations are formed for magnetic vector potential in each sub-region. Applying curl on the obtained results leads to calculating the magnetic flux density components in each sub-region. Based on the superposition theorem, the analytical procedure is utilized in the two separate steps where in the first step the magnetic flux is originated by only PMs with various magnetization patterns (i.e., parallel, ideal Halbach, 2-segment Halbach and bar magnet in shifting magnetization patterns) and the armature currents are zero. In the second step, all PMs are inactivated and only armature currents affect the magnetic flux distribution. Finally, the obtained analytical results are compared with those of the Finite element method (FEM) to confirm the accuracy of the proposed analytical model. The extracted results reveal the benefit of the analytical model for replacing instead of the FEM to predict the magnetic flux density component in the presented AFPMBMs in a shorter time.

Comparative study of thrust of U-shaped ironless permanent magnet synchronous linear motor based on analytical method and finite element analysis

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1091-1101
Author(s):  
Zhihui Yang ◽  
Ren Liu ◽  
Bin Xia
Keyword(s):  
Magnetic Field ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Permanent Magnet ◽  
Edge Effect ◽  
Three Dimensional ◽  
Linear Motor ◽  
Air Gap ◽  
Element Analysis ◽  
Air Gap Magnetic Field

Due to the large transverse edge effect for U-shaped ironless permanent magnet synchronous linear motor affect the distribution of air gap magnetic field is large, it will reduce the no-load back electromotive force and thrust. This paper proposes a novel method to evaluate the effect of transverse edge effect based on Kriging surrogate model. By comparing the results of the two-dimensional and three-dimensional finite element analysis of the air gap magnetic field of the motor, it can be seen transverse length of the motor, air gap height and thickness of the permanent magnet are the main influencing factors.

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