Analytical model for the minimization of torque ripple in permanent magnets assisted synchronous reluctance motors through asymmetric rotor poles

2015 ◽  
Author(s):  
Alejandro J. Pina ◽  
Haiwei Cai ◽  
Yazan Alsmadi ◽  
Longya Xu
Keyword(s):  
Analytical Model ◽  
Permanent Magnets ◽  
Torque Ripple ◽  
Rotor Poles ◽  
Asymmetric Rotor

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.

Study and design of dual stator permanent magnet machine with spoke-type configurations using phase-group concentrated-coil windings

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1381-1389
Author(s):  
Dezhi Chen ◽  
Chengwu Diao ◽  
Zhiyu Feng ◽  
Shichong Zhang ◽  
Wenliang Zhao
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Low Cost ◽  
Dynamic Performance ◽  
Torque Ripple ◽  
Permanent Magnet Machine ◽  
Torque Density ◽  
Phase Group ◽  
High Torque ◽  
Simulation Results

In this paper, a novel dual-stator permanent magnet machine (DsPmSynM) with low cost and high torque density is designed. The winding part of the DsPmSynM adopts phase-group concentrated-coil windings, and the permanent magnets are arranged by spoke-type. Firstly, the winding structure reduces the amount of copper at the end of the winding. Secondly, the electromagnetic torque ripple of DsPmSynM is suppressed by reducing the cogging torque. Furthermore, the dynamic performance of DsPmSynM is studied. Finally, the experimental results are compared with the simulation results.

scholarly journals Design and Analysis of a Novel Axial-Radial Flux Permanent Magnet Machine with Halbach-Array Permanent Magnets

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3639
Author(s):  
Rundong Huang ◽  
Chunhua Liu ◽  
Zaixin Song ◽  
Hang Zhao
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Torque Ripple ◽  
Axial Flux ◽  
Element Analysis ◽  
Torque Density ◽  
Axial Forces ◽  
Halbach Array ◽  
Radial Flux ◽  
High Torque

Electric machines with high torque density are needed in many applications, such as electric vehicles, electric robotics, electric ships, electric aircraft, etc. and they can avoid planetary gears thus reducing manufacturing costs. This paper presents a novel axial-radial flux permanent magnet (ARFPM) machine with high torque density. The proposed ARFPM machine integrates both axial-flux and radial-flux machine topologies in a compact space, which effectively improves the copper utilization of the machine. First, the radial rotor can balance the large axial forces on axial rotors and prevent them from deforming due to the forces. On the other hand, the machine adopts Halbach-array permanent magnets (PMs) on the rotors to suppress air-gap flux density harmonics. Also, the Halbach-array PMs can reduce the total attracted force on axial rotors. The operational principle of the ARFPM machine was investigated and analyzed. Then, 3D finite-element analysis (FEA) was conducted to show the merits of the ARFPM machine. Demonstration results with different parameters are compared to obtain an optimal structure. These indicated that the proposed ARFPM machine with Halbach-array PMs can achieve a more sinusoidal back electromotive force (EMF). In addition, a comparative analysis was conducted for the proposed ARFPM machine. The machine was compared with a conventional axial-flux permanent magnet (AFPM) machine and a radial-flux permanent magnet (RFPM) machine based on the same dimensions. This showed that the proposed ARFPM machine had the highest torque density and relatively small torque ripple.

Torque ripple optimization for synchronous reluctance motors based on a virtual permanent magnet harmonic machine model

2021 ◽  
Vol 67 (3) ◽  
pp. 327-338
Author(s):  
Yixiang Xu ◽  
Chong Di ◽  
Xiaohua Bao ◽  
Dongying Xu
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Torque Ripple ◽  
Air Gap ◽  
Analysis Model ◽  
Machine Model ◽  
Asymmetric Rotor ◽  
Rotor Flux ◽  
Air Gap Magnetic Field ◽  
Intermediate Variables

The torque ripple is affected by both the stator and the rotor magnetic field harmonics. In synchronous reluctance motors (SynRM), there are only rotor permeance harmonics existing on the rotor side for the absence of the rotor windings. Since the asymmetric rotor flux barriers are widely applied in the SynRM rotor, it is difficult to calculate the rotor permeance accurately by the analytical method. In this article, the effects of the rotor permeance harmonics on the air-gap magnetic field are studied by a virtual permanent magnet harmonic machine (VPMHM), which is a finite-element (FE) based magnetostatic analysis model. The air-gap flux density harmonics produced by the SynRM rotor are extracted from the VPMHM model and used as the intermediate variables for the torque ripple optimization. The proposed method does not need to solve the transient process of motor motion. Hence, the time of the optimization process can be significantly shortened. Finally, a full electric cycle is simulated by dynamic FE simulation, and the torque ripple is proved to be effectively reduced.

Reduction in Torque Ripple by Applying an Asymmetric Rotor to PMSM

2021 ◽  
Vol 141 (6) ◽  
pp. 445-452
Author(s):  
Makoto Ito ◽  
Shinji Sugimoto ◽  
Akeshi Takahashi ◽  
Shuichi Tamiya ◽  
Takatoshi Kushida
Keyword(s):  
Torque Ripple ◽  
Asymmetric Rotor

scholarly journals Exact Two-Dimensional Analytical Calculations for Magnetic Field, Electromagnetic Torque, UMF, Back-EMF, and Inductance of Outer Rotor Surface Inset Permanent Magnet Machines

2019 ◽  
Vol 24 (1) ◽  
pp. 24 ◽  
Author(s):  
AmirAbbas Vahaj ◽  
Akbar Rahideh ◽  
Hossein Moayed-Jahromi ◽  
AliReza Ghaffari
Keyword(s):  
Permanent Magnet ◽  
Analytical Model ◽  
Permanent Magnets ◽  
Optimization Problems ◽  
Magnetic Flux Density ◽  
Permanent Magnet Machines ◽  
Two Dimensional ◽  
Electromagnetic Torque ◽  
Outer Rotor ◽  
Rotor Surface

This paper presents a two-dimensional analytical model of outer rotor permanent magnet machines equipped with surface inset permanent magnets. To obtain the analytical model, the whole model is divided into the sub-domains, according to the magnetic properties and geometries. Maxwell equations in each sub-domain are expressed and analytically solved. By using the boundary/interface conditions between adjacent sub-regions, integral coefficients in the general solutions are obtained. At the end, the analytically calculated results of the air-gap magnetic flux density, electromagnetic torque, unbalanced magnetic force (UMF), back-electromotive force (EMF) and inductances are verified by comparing them with those obtained from finite element method (FEM). One of the merits of this method in comparison with the numerical model is the capability of rapid calculation with the highest precision, which made it suitable for optimization problems.

scholarly journals Yokeless Axial Flux Surface-Mounted Permanent Magnets Machine Rotor Parameters Influence on Torque and Back-Emf

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3418
Author(s):  
Stanisław J. Hajnrych ◽  
Rafał Jakubowski ◽  
Jan Szczypior
Keyword(s):  
Permanent Magnets ◽  
Torque Ripple ◽  
Air Gap ◽  
Electric Machine ◽  
Axial Flux ◽  
Flux Surface ◽  
Cogging Torque ◽  
Torque Density ◽  
3D Fea ◽  
The Common

The paper presents the results of a 3D FEA simulations series of a dual air gap Axial Flux (AF) electric machine with Surface-Mounted Permanent magnets (SPM) with parameterized rotor geometry. Pole number and pole span influence on back-emf, as well as cogging and ideal electromagnetic torques angular characteristics were investigated for each model with the common segmented yokeless stator with concentric windings. Synchronous and BLDC drives supply were used to estimate back-emf distortion. Ideal torque ripple and cogging torque spectra were analyzed. It was concluded that the number of poles closer to the number of slots with ~0.8 pole span tends to yield good torque density with the lowest cogging torque, back-emf distortion and ideal torque ripple.

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