MAGNETOSTATIC FIELD ANALYSIS OF DC COMMUTATOR MOTORS WITH GEAR-TEETH ON THE ROTOR

2017 ◽  
Vol 41 (4) ◽  
pp. 555-569
Author(s):  
Guan-Chen Chen ◽  
Hong-Sen Yan
Keyword(s):  
Flux Density ◽  
Magnetic Circuit ◽  
Torque Ripple ◽  
Open Circuit ◽  
Air Gap ◽  
Field Analysis ◽  
Element Analysis ◽  
Magnetostatic Field ◽  
Gear Teeth ◽  
Torque Ripples

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.

Magnetostatic Field Analysis of Disk-Type Permanent-Magnet Motors

2013 ◽  
Vol 479-480 ◽  
pp. 390-395
Author(s):  
Yi Chang Wu ◽  
Yi Cheng Hong
Keyword(s):  
Finite Element ◽  
Permanent Magnet ◽  
Magnetic Circuit ◽  
Computing Time ◽  
Circuit Model ◽  
Field Analysis ◽  
Permanent Magnet Motors ◽  
Element Analysis ◽  
Magnetostatic Field ◽  
Acceptable Error

The aim of this paper is to analyze the magnetostatic field of disk-type permanent-magnet motors by utilizing the 1-D equivalent magnetic circuit approach and the finite-element method. A 1-D equivalent magnetic circuit model, which is analogous to an electric circuit model, of the disk-type permanent-magnet motor is proposed. The accuracy of the analytical model is verified by a commercial 3-D finite-element analysis (FEA) package. The result shows that the air-gap flux density is in good agreement with an acceptable error of about 1.66%. The presented magnetic circuit approach is not only an accurate technique in predicting the magnetostatic field of disk-type permanent-magnet motors, but also effectively reduces the computing time. It is especially suitable for the preliminary design and optimization of permanent-magnet motors with axial-flux topologies.

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.

Finite-Element Analysis of the Magnetostatic Field of a Coaxial Magnetic Gear Device

2015 ◽  
Vol 764-765 ◽  
pp. 289-293
Author(s):  
Yi Chang Wu ◽  
Han Ting Hsu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Magnetic Flux ◽  
High Speed ◽  
Field Analysis ◽  
Element Analysis ◽  
Magnetostatic Field ◽  
Speed Reduction ◽  
Dimensional Finite Element ◽  
Magnetic Gear

This paper presents the magnetostatic field analysis of a coaxial magnetic gear device proposed by Atallah and Howe. The structural configuration and speed reduction ratio of this magnetic gear device are introduced. The 2-dimensional finite-element analysis (2-D FEA), conducted by applying commercial FEA software Ansoft/Maxwell, is performed to evaluate the magnetostatic field distribution, especially for the magnetic flux densities within the outer air-gap. Once the number of steel pole-pieces equals the sum of the pole-pair numbers of the high-speed rotor and the low-speed rotor, the coaxial magnetic gear device possesses higher magnetic flux densities, thereby generating greater transmitted torque.

Analytical sub-domain model for predicting open-circuit field of permanent magnet vernier machine accounting for tooth tips

2016 ◽  
Vol 35 (2) ◽  
pp. 624-640 ◽  
Author(s):  
Y. Oner ◽  
Z.Q. Zhu ◽  
L.J. Wu ◽  
X. Ge
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Open Circuit ◽  
Air Gap ◽  
Domain Model ◽  
Direct Drive ◽  
Element Analysis ◽  
Cogging Torque ◽  
Content Type ◽  
Flux Modulation

Purpose – Due to high electromagnetic torque at low speed, vernier machines are suitable for direct-drive applications such as electric vehicles and wind power generators. The purpose of this paper is to present an exact sub-domain model for analytically predicting the open-circuit magnetic field of permanent magnet vernier machine (PMVM) including tooth tips. The entire field domain is divided into five regions, viz. magnets, air gap, slot openings, slots, and flux-modulation pole slots (FMPs). The model accounts for the influence of interaction between PMs, FMPs and slots, and radial/parallel magnetization. Design/methodology/approach – Magnetic field distributions for slot and air-gap, flux linkage, back-EMF and cogging torque waveforms are obtained from the analytical method and validated by finite element analysis (FEA). Findings – It is found that the developed sub-domain model including tooth tips is very accurate and is applicable to PMVM having any combination of slots/FMPs/PMs. Originality/value – The main contributions include: accurate sub-domain model for PMVM is proposed for open-circuit including tooth-tip which cannot be accounted for in literature; the model accounts the interaction between flux modulation pole (FMP) and slot; developed sub-domain model is accurate and applicable to any slot/FMP/PM combinations; and it has investigated the influence of FMP/slot opening width/height on cogging torque.

An analytical model for predicting noise radiated by switch reluctance electric motors

2021 ◽  
Vol 263 (2) ◽  
pp. 4100-4110
Author(s):  
Murat Inalpolat ◽  
Bahadir Sarikaya ◽  
Enes Timur Ozdemir ◽  
Hyun Ku Lee
Keyword(s):  
Magnetic Energy ◽  
Cost Effective ◽  
Torque Ripple ◽  
Air Gap ◽  
Sound Power ◽  
Electromagnetic Forces ◽  
Phase Switching ◽  
Proposed Model ◽  
Torque Ripples

Switch reluctance motors (SRM) have become a prominent alternative for electric vehicles in recent years due to their simple, high power density architecture and cost-effective manufacturability. Despite its potential, NVH problems have been one of the biggest challenges for SRM's implementation. Vibration and noise generated by the SRM are mainly caused by phase switching related torque ripple, unbalanced electromagnetic forces from air gap variations and lamination problems. Our proposed model is an analytical noise radiation prediction model which relates geometrical, material and electrical design inputs to radiated sound power. The electromagnetic part of the model is nonlinear with saturation and provides back-emf and flux linkage by receiving design inputs. The computed magnetic energy, radial and tangential rotor forces are utilized as excitation sources to a continuous shell dynamic model to obtain the steady-state vibration response. Finally, surface velocities obtained from the shell model are used to calculate sound power. Utilizing a shell structure provides axial, radial and tangential information on the casing by considering the effect of magneto-restrictive forces of laminations, torque ripples and unbalanced electromagnetic forces. The effect of air gap, lamination error, and stator and rotor geometry on sound radiation are studied through an example case study.

Magnetic Field Analysis of Surface-Mounted Permanent-Magnet Motors

2011 ◽  
Vol 52-54 ◽  
pp. 285-290
Author(s):  
Yi Chang Wu ◽  
Feng Ming Ou ◽  
Bo Wei Lin
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Magnetic Circuit ◽  
Circuit Model ◽  
Field Analysis ◽  
Permanent Magnet Motors ◽  
Element Analysis ◽  
Magnetic Field Analysis ◽  
Field Estimation ◽  
The Magnetic Field

The prediction of the magnetic field is a prerequisite to investigate the motor performance. This paper focuses on the magnetic field estimation of surface-mounted permanent-magnet (SMPM) motors based on two approximations, i.e., the magnetic circuit analysis and the finite-element analysis (FEA). An equivalent magnetic circuit model is applied to analytically evaluate the magnetic field of a SMPM motor with exterior-rotor configuration. The two-dimensional FEA is then applied to numerically calculate the magnetic field and to verify the validity of the magnetic circuit model. The results show that the errors between the analytical predictions and FEA results are less than 6%. It is of benefit to further design purposes and optimization of SMPM motors.

scholarly journals Noise Reduction Design with Trapezoidal Back-EMF and Asymmetric Air-Gap for Single-Phase BLDC Refrigerator Cooling Fan Motor

Energies ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 5467
Author(s):  
Jin-Hwan Lee ◽  
Sang-Yong Jung
Keyword(s):  
Single Phase ◽  
Three Dimensional ◽  
Torque Ripple ◽  
Air Gap ◽  
Manufacturing Cost ◽  
Element Analysis ◽  
Dimensional Finite Element ◽  
Novel Method ◽  
The Dead ◽  
Three Dimensional Finite Element

In this study, a novel method for reducing the noise generated by single-phase claw-pole motors employed as refrigerator fan blowers is proposed. A single-phase claw-pole motor has the advantages of low manufacturing cost, easy manufacturing, and a high number of turns. However, in such motors, current delays occur owing to a high inductance; therefore, it is necessary to merge the back-electromotive force and current phases into the same phase using the phase advance method. Additionally, a single-phase motor exhibits dead torque and zero torque at an electrical angle of 180° owing to its electrical characteristics, and the dead torque deteriorates the average torque and torque ripple characteristics of the motor. In this study, a novel method is proposed to make the air gap asymmetrical by tilting the claw to reduce the noise generated by single-phase claw-pole motors. An asymmetric air gap allows the cogging torque to eliminate the dead torque caused by alignment torques, causing the torque ripple to decrease. To validate the effectiveness of the proposed method, the proposed model is compared with a base model via three-dimensional finite element analysis. Furthermore, the two models are manufactured and a noise test is conducted in an anechoic chamber to compare the noise difference between the two models.

Sinusoidal PWM Techniques in Rotor Pole Segmentation to Reduce Permanent Magnet Synchronous Machine Torque Ripple

2020 ◽  
Author(s):  
Khristian M. de Andrade Jr ◽  
Hugo E. Santos ◽  
Wellington M. Vilela, ◽  
Geyverson T. de Paula
Keyword(s):  
Permanent Magnets ◽  
Torque Ripple ◽  
Synchronous Machine ◽  
Element Analysis ◽  
Cogging Torque ◽  
Torque Ripple Reduction ◽  
Rotor Poles ◽  
Rotor Pole ◽  
Ripple Reduction ◽  
Torque Ripples

Torque ripples can cause mechanical stress in electrical machines, among otherproblems. The present paper proposes three methods to reduce these ripples in the permanent magnets synchronous machine considering rotor poles design. These methods consist in segmenting the rotor poles, with width and distances between segments obtained by SPWM techniques. The modulating wave is a sinwave which has the same frequency as the air gap flux density fundamental harmonic. Method 1 contemplates the unipolar SPWM technique, whereas methods 1 and 2 used the bipolar SWPM technique. Furthermore, the equations used to predict the cogging torque behavior are presented and verified by means of a finite element analysis. The torque ripple reduction is achieved due to the elimination of back-electromotive force harmonics and the decrease in the cogging torque peak. Method 1 has proved to be the most effective, reducing the torque ripple by 51.38% and 76.61% for the 4-pole and 8-pole machines, respectively. In addition, the magnet volume utilized has been reduced by 22.55% for the 4-pole machine, but the average torque value has been reduced by 18.7%. It is worth mentioning that the proposed methods do not require skewing to reduce the torque ripple.

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