scholarly journals Fast analytical calculation of the air-gap flux density in an outer-rotor permanent-magnet brushless motor

2018 ◽  
Vol 189 ◽  
pp. 06008
Author(s):  
Shuaichen Ye ◽  
Xiaoxian Yao
Keyword(s):  
Permanent Magnet ◽  
Flux Density ◽  
Analytical Method ◽  
Analytical Calculation ◽  
Air Gap ◽  
Element Analysis ◽  
Design And Optimization ◽  
Brushless Motor ◽  
Practical Engineering ◽  
Analytical Result

The air-gap flux density must be considered in the design and optimization of the structure parameters of permanent-magnet brushless motors (PMBMs). Existing methods for calculating the air-gap flux density are complex and thus cannot be easily applied in practical engineering. This paper presents a fast analytical method for calculating the air-gap flux density that is more efficient and practicable than existing methods. A lumped magnetic circuit model is presented to illustrate the proposed method. Then, the analytical result and finite element analysis (FEA) results obtained for a PMBM prototype are compared. The results indicate that the error between the two methods does not exceed 5%. Therefore, the proposed analytical method is highly efficient and accurate, which may be applied in the motor pro-design process of many engineering instruments.

A novel analytical calculation of magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping

2020 ◽  
pp. 1-15
Author(s):  
Jianqi Li ◽  
Yu Zhou ◽  
Jianying Li
Keyword(s):  
Magnetic Field ◽  
Conformal Mapping ◽  
Permanent Magnet ◽  
Flux Density ◽  
Analytical Method ◽  
Electromotive Force ◽  
Analytical Calculation ◽  
Air Gap ◽  
Permanent Magnet Machines ◽  
Peak Value

This paper presented a novel analytical method for calculating magnetic field in the slotted air gap of spoke-type permanent-magnet machines using conformal mapping. Firstly, flux density without slots and complex relative air-gap permeance of slotted air gap are derived from conformal transformation separately. Secondly, they are combined in order to obtain normalized flux density taking account into the slots effect. The finite element (FE) results confirmed the validity of the analytical method for predicting magnetic field and back electromotive force (BEMF) in the slotted air gap of spoke-type permanent-magnet machines. In comparison with FE result, the analytical solution yields higher peak value of cogging torque.

Analytical Calculation of Slotless Permanent Magnet Motor Based on Soft Ferrite

2013 ◽  
Vol 397-400 ◽  
pp. 501-504
Author(s):  
Xin Yi Zhang ◽  
Xing Hua Wang ◽  
Ming Hui Li ◽  
Xue Qin Zhang
Keyword(s):  
Finite Elements ◽  
Permanent Magnet ◽  
High Speed ◽  
Analytical Calculation ◽  
Air Gap ◽  
Permanent Magnet Motor ◽  
Leakage Flux ◽  
Brushless Motor ◽  
Prototype Test ◽  
Soft Ferrite

High-speed slotless permanent magnet brushless motor based on soft ferrite adopts a large effective air gap structure. For the large effective air-gap, the air-gap flux distribution becomes uneven and the end leakage flux significantly increases. Thus, the traditional analytical method of the phase EMF is inapplicable. This paper deduces the analytical expression of the phase EMF based on the analytical calculation of the air-gap field and analyzes the distribution of the end leakage flux by 3D finite elements methods. Then the end leakage flux is considered by a correction factor of the core length. Finally the analytical calculation method is proved to be feasible by the comparison between the finite elements results and the prototype test results.

Analysis of Halbach Permanent Magnet Synchronous Motor with Ironless Rotor Based on AYSYS

2014 ◽  
Vol 556-562 ◽  
pp. 1404-1407
Author(s):  
Hao Ming Zhang ◽  
Lian Soon Peh ◽  
Ying Hai Wang
Keyword(s):  
Finite Element Analysis ◽  
Permanent Magnet ◽  
Flux Density ◽  
Permanent Magnet Synchronous Motor ◽  
Air Gap ◽  
High Power Density ◽  
Permanent Magnet Motor ◽  
Element Analysis ◽  
The Relationship ◽  
The Ideal

Modern motor needs high power density and low rotary inertia,which can improve its dynamic characteristics.Traditional permanent magnet motor shows its limitations.A new structure of ironless rotor motor is proposed. Finite element analysis based on ANSYS proves that the new design not only can increase the motor air gap flux density, but can make the use of ironless rotor rotor become reality. From the relationship curve between air gap flux density and ironless material width, can easily find the ideal width of ironless material of the motor.

scholarly journals A Study on a Slotless Brushless DC Motor with Toroidal Winding

Processes ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1881
Author(s):  
Ho-Young Lee ◽  
Seung-Young Yoon ◽  
Soon-O Kwon ◽  
Jin-Yeong Shin ◽  
Soo-Hwan Park ◽  
...  
Keyword(s):  
Flux Density ◽  
Analytical Method ◽  
Air Gap ◽  
Element Analysis ◽  
Tooth Structure ◽  
Brushless Dc ◽  
And Performance ◽  
Winding Angle ◽  
Winding Factor ◽  
Motor Structure

In this study we developed a brushless DC (BLDC) slotless motor with toroidal winding. The proposed toroidal winding is a method of winding a coil around a ring-type stator yoke in the circumferential direction. As there is no need for a slot or tooth structure, it can be designed with a slotless motor structure that is advantageous for vibration and noise. The basic principle of operation and motor characteristics of a slotless motor with toroidal winding were explained using an analytical method and finite element analysis (FEA). Further, the air gap flux density, winding factor, and back electromotive force (EMF) for changes in the winding angle and number of coil turns were calculated using the analytical method and compared with the FEA results. Finally, the resistance, back EMF, cogging torque, and performance of the prototype were measured and compared with the FEA results. The results show that the air gap flux density and winding factor were approximately the same with an error of <2%, while the back EMF had an error of ~10% from the analysis result. Thus, the proposed slotless motor provides a basic design for conveniently manufacturing brushless DC (BLDC) slotless motors with toroidal windings.

scholarly journals Electromagnetic Analysis and Performance Investigation of a Flux-Switching Permanent Magnet Machine

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3362 ◽  
Author(s):  
Azeem ◽  
Kim
Keyword(s):  
Permanent Magnet ◽  
Flux Density ◽  
Air Gap ◽  
Stator Core ◽  
Element Analysis ◽  
Optimal Value ◽  
Rotor Poles ◽  
Slot Opening ◽  
And Performance ◽  
Design Factors

This paper aims to present a general and effective analytical approach to calculate the air gap flux density and the back electromotive force (EMF) of a flux-switching permanent magnet (FSPM) machine. The proposed analytical expression of the air gap flux density is based on an improved air gap permeance function considering the geometries of slotted stator core pieces and magnets between stator teeth as well as the salient rotor poles. The back EMF equation is accurately derived using the proposed air gap flux density equation expressed in terms of practical machine dimensions and thus it provides the key design factors as well as details of the back EMF production mechanism. To validate the proposed analytical expressions, they are applied to the case study of a 12-slot 10-pole FSPM machine, and the finite element analysis results confirm the analytical predictions. Besides, for the proposed analytical model, the effects of the machine’s geometries on back EMF characteristics are investigated. The investigation shows that the ratio of rotor slot opening to slot pitch has a significant effect on the back EMF, and its optimal value is suggested. The proposed equations also provide a mean to choose the slot and pole combinations to obtain a higher power density.

An Exact Analytical Solution of Halbach Arrays Permanent-Magnet Motor for Magnetic Field on Load

2013 ◽  
Vol 416-417 ◽  
pp. 58-65 ◽  
Author(s):  
Chen Li ◽  
Hang Zhang ◽  
Li Bing Jing ◽  
Yue Jin Zhang ◽  
Jie Bao Li
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Flux Density ◽  
Analytical Method ◽  
Exact Analytical Solution ◽  
Air Gap ◽  
Reaction Field ◽  
Armature Reaction ◽  
Air Gap Magnetic Field ◽  
Halbach Arrays

An exact analytical model of Halbach arrays permanent-magnet (PM) motor is established for the calculation of air-gap magnetic field on load in this paper. The exact analytical method is based on the resolution of Laplaces or Poissons equations by applying the boundary conditions on the interface between each sub-domain: air-gap, Halbach arrays and slots. The waveforms of no-load magnetic field flux density, back electromotive force (EMF), armature reaction field flux density, air-gap magnetic field flux density on load and electromagnetic torque, which computed by the analytical method were validated through the finite-element method (FEM).

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.

Cogging Torque Reduction by Means of Pole Segmentation Optimization on the Permanent Magnet Synchronous Machine

2020 ◽  
Author(s):  
Hugo E. Santos ◽  
Khristian M. de Andrade Jr. ◽  
Wellington M. Vilela ◽  
Geyverson T. de Paula
Keyword(s):  
Permanent Magnet ◽  
Flux Density ◽  
Torque Ripple ◽  
Air Gap ◽  
Optimization Techniques ◽  
Machine Construction ◽  
Permanent Magnet Machines ◽  
Element Analysis ◽  
Cogging Torque ◽  
Main Component

One of the main obstacles during the design of permanent magnet machines consists in reducing the developed torque ripple characteristic of this type of machine. The main component of such ripples is a parasitic torque, called cogging torque. A technique present in the literature to reduce this parasitic torque considers the segmentation of the poles. This allows a decrease in the cogging torque, however reducing the air gap flux density too and thus the torque mean. Thus, in order to keep the torque mean reduction in reasonable levels, optimization techniques can be employed with the pole segmentation. The variables to be optimized are the number, distance and width of the segments. The present article proposes two methods to optimize these variables in order to minimize the cogging torque, but also maintain a satisfactory flux density value. Some constraints are added to account for the machine construction feasibility. The proposed methods were validated through a nite element analysis. The results proved the effectiveness of the proposed methods, with a reduction by up to 76% in the cogging torque and keeping, in the best case, about 95% of the reference machine air gap flux density and 78% in the worst one.

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