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 ◽  
...  

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.

2018 ◽  
Vol 189 ◽  
pp. 06008
Author(s):  
Shuaichen Ye ◽  
Xiaoxian Yao

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.


Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3362 ◽  
Author(s):  
Azeem ◽  
Kim

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.


Author(s):  
Jianqi Li ◽  
Yu Zhou ◽  
Jianying Li

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.


2014 ◽  
Vol 556-562 ◽  
pp. 1404-1407
Author(s):  
Hao Ming Zhang ◽  
Lian Soon Peh ◽  
Ying Hai Wang

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.


In this paper, the field analysis of the sleeve-rotor induction motor taking the rings effect into consideration is carried out using the Maxwell’s field equations. A model in cylindrical coordinates is used to establish the rotor-rings and to solve the air gap magnetic field. The flux density is assumed to be constant through the very small air gap length while the skin effect through the axial rotor length is considered. The axial distribution of the air gap flux density, the sleeve current density components and the force density are obtained. The motor performance is carried out taking into account the effects of the sleeve rings performance characteristics. The effects of design data on the starting torque and the overload capacity of the motor are also considered.


2013 ◽  
Vol 416-417 ◽  
pp. 58-65 ◽  
Author(s):  
Chen Li ◽  
Hang Zhang ◽  
Li Bing Jing ◽  
Yue Jin Zhang ◽  
Jie Bao Li

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).


2020 ◽  
Author(s):  
Hugo E. Santos ◽  
Khristian M. de Andrade Jr. ◽  
Wellington M. Vilela ◽  
Geyverson T. de Paula

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.


2017 ◽  
Vol 41 (4) ◽  
pp. 555-569
Author(s):  
Guan-Chen Chen ◽  
Hong-Sen Yan

This paper presents the open-circuit magnetostatic field analysis of a DC commutator motor by applying 1-D and 2-D equivalent magnetic circuit methods. For the 1-D and 2-D equivalent magnetic circuit method, the average air-gap flux density of a DC commutator motor and magnetic flux in every node are derived respectively, and the validity is verified by the finite-element analysis. The Carter’s coefficient is applied to model the permeance of the slot and gear-teeth space. The differences of the air-gap flux density are 3.21% and 3.06% for 1-D and 2-D methods, respectively. The flux linkages, back-EMF constants, cogging torques, electromagnetic torques, and torque ripples of the two gear profiles with feasible number of teeth integrated on the rotor are analyzed to verify the effects of gear profiles. The result shows that the gear-teeth integrated on the motor act as dummy slots, which reduce the cogging torque and torque ripple by 92.02% and 50.14 %, respectively.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 667-674
Author(s):  
Muhammad Azeem ◽  
Byungtaek Kim

This paper examines the influence of pole and slot combinations on the electromagnetic performance of the flux-switching permanent magnet (FSPMs) machine. For this purpose, first the production of air gap flux density in machine analytically discussed. Next, five different pole and slot combination are selected by using the knowledge of air-gap flux density expression. The performances of the different combinations are analyzed and compared using the finite element analysis (FEA), and optimal pole and slot combination is suggested. It is found that the pole and slot combination has a dominant effect on machine performance and needs to be considered during the design stage.


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