scholarly journals The Effect of Magnet Structure on the Cogging Torque Reduction in a Permanent Magnet Generator

2021 ◽  
Vol 56 (1) ◽  
Author(s):  
Tajuddin Nur ◽  
Yudha Suherman ◽  
Herlina
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Magnetic Surface ◽  
Electric Machines ◽  
Magnetic Method ◽  
Cogging Torque ◽  
The Core ◽  
Initial Design ◽  
Simulation Results ◽  
Peak Value

The cogging torque would still be a constant part of permanent magnet-electric machines. This happens because of the construction in which permanent magnets are attached to the rotor, and a slot is present at the core of the stator. The contact between the two, related to the distance between the magnetic surface and the stator slot, makes it challenging to eliminate the cogging torque. This study aims to maximize cogging torque by reducing it with a new method. The proposed method is a mixture of two techniques that indicate significant promise. This invention mixes two techniques to improve the final results. The first process is called magnetic edge shaping, and the second technique is called a dummy slot on the stator. A fractional slot number (FSN) type with 24 slots and 18 poles is the permanent magnet machine used for this investigation. This work is assisted by software version 4.2 of the Finite Element Magnetic Method (FEMM), which will simulate the original and the proposed design. The proposed method proved to be effective in minimizing the peak value of the cogging torque, as shown by the simulation results of 98% of the initial design. Combining the two techniques may reduce the tangential value of the flux so that the flux leading to the slot is lower than the initial design.

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.

Modeling and Design of Permanent Magnet Vibration-to-Electrical Power Generator’s Induction Coil

2012 ◽  
Vol 588-589 ◽  
pp. 614-617
Author(s):  
Zhi Hua Wang ◽  
Mei Ling Li ◽  
Jian Zhang ◽  
Li Wang ◽  
Yong Xu
Keyword(s):  
Permanent Magnet ◽  
Electrical Power ◽  
Induction Coil ◽  
Test Results ◽  
Coil Design ◽  
Sinusoidal Vibration ◽  
Electrical Generator ◽  
Simulation Results ◽  
Peak Value

The Equivalent Turn Number of Coil (ETNC) is proposed for induction coil design. Simulation results show that the vibrationonthe induction coil’s structure. The optimized coil is composed by two symmetry parts on the condition of sinusoidal vibration. The effective value of output EMF of optimized coil increases 51.39% than uniform coil’s. In the experiment, the optimized and uniform coils are fabricated with 600 turns and comparatively studied in the same vibration-to-electrical generator. The test results show that the peak-to-peak value and effective value of output EMF of the optimized coil can increase up to 52.59% and 48.76%, respectively, compared with the uniform coil.

scholarly journals Mitigation Method of Slot Harmonic Cogging Torque Considering Unevenly Magnetized Permanent Magnets in PMSM

Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3887
Author(s):  
Jeong ◽  
Lee ◽  
Hur
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Permanent Magnet Synchronous Motor ◽  
Harmonic Component ◽  
Magnetic Flux Density ◽  
Element Analysis ◽  
Cogging Torque ◽  
Maxwell Stress Tensor ◽  
The Finite Element Analysis ◽  
Harmonic Components

This paper presents a mitigation method of slot harmonic cogging torque considering unevenly magnetized magnets in a permanent magnet synchronous motor. In previous studies, it has been confirmed that non-uniformly magnetized permanent magnets cause an unexpected increase of cogging torque because of additional slot harmonic components. However, these studies did not offer a countermeasure against it. First, in this study, the relationship between the residual magnetic flux density of the permanent magnet and the cogging torque is derived from the basic form of the Maxwell stress tensor equation. Second, the principle of the slot harmonic cogging torque generation is explained qualitatively, and the mitigation method of the slot harmonic component is proposed. Finally, the proposed method is verified with the finite element analysis and experimental results.

The Method Pole of Width Modulation Reducing Cogging Torque in Permanent Magnet Motor

2012 ◽  
Vol 433-440 ◽  
pp. 4201-4206
Author(s):  
Yue Jun An ◽  
Wen Qiang Zhao ◽  
Li Ping Xue ◽  
Hong Liang Wen ◽  
Guo Ming Liu
Keyword(s):  
Permanent Magnet ◽  
Torque Ripple ◽  
Experimental Result ◽  
Testing System ◽  
Permanent Magnet Motors ◽  
Permanent Magnet Motor ◽  
Surface Type ◽  
Angle Sensor ◽  
Cogging Torque ◽  
Simulation Results

Cogging torque is one of the most important parameters of permanent magnet motors, which causes torque ripple, vibration and noise. This paper describes the mechanism of cogging torque, introduces several methods of reducing cogging torque and points out the advantage of novel magnet arrayed permanent magnet motor in reducing cogging torque. Ansoft software is used to build the simulation of conventional surface-type permanent magnet motor and novel magnet arrayed permanent magnet motor and to calculate their cogging torque. a cogging torque testing system which included the angle sensor, permanent magnet motor, torque wrenches and other components are tested two different structures motors’ cogging torque .The experimental result is consistent with the simulation results, it shows that the method of novel magnet arrayed permanent magnet motor reducing cogging torque is correct. The new method compare with the same specification on the surface of permanent magnet motor can reduce more cogging torque.

The Origin of Permanent Magnet Induced Vibration in Electric Machines

1991 ◽  
Vol 113 (4) ◽  
pp. 476-481 ◽  
Author(s):  
B. S. Rahman ◽  
D. K. Lieu
Keyword(s):  
Permanent Magnet ◽  
Motor Performance ◽  
Permanent Magnets ◽  
Electric Machines ◽  
Permanent Magnet Motors ◽  
Forcing Function ◽  
Surrounding Structure ◽  
Resonant Modes ◽  
Principal Source ◽  
The Magnetic Field

A principal source of vibration in permanent magnet motors and generators is the induced travelling forces from the rotating permanent magnets acting on the stator. The form of the magnetic field and resulting forcing function in the airgap of such machines is critical. The stator is modelled as a solid ring, with no teeth. Various motor parameters were investigated, including the effects of radial versus parallel magnetization, magnetization tolerances, and radial offset. The results were determined with analytical and FEM models. It was concluded that radial magnetization of the permanent magnets was preferable for both vibration and motor performance. Magnetization tolerances and radial offsets yielded a relatively more populated frequency spectrum for the forcing function and thus could lead to a greater probability of resonant modes being excited in the surrounding structure.

A new optimal design of surface mounted permanent magnet synchronous motors with integral slot per pole

2018 ◽  
Vol 37 (1) ◽  
pp. 136-152
Author(s):  
Behrooz Rezaeealam ◽  
Farhad Rezaee-Alam
Keyword(s):  
Magnetic Field ◽  
Optimal Design ◽  
Permanent Magnet ◽  
Permanent Magnets ◽  
Air Gap ◽  
Permanent Magnet Synchronous Motors ◽  
Cogging Torque ◽  
Content Type ◽  
Synchronous Motors ◽  
Air Gap Magnetic Field

Purpose The purpose of this paper is to present a new optimal design for integral slot permanent magnet synchronous motors (PMSMs) to shape the air-gap magnetic field in sinusoidal and to reduce the cogging torque, simultaneously. Design/methodology/approach For obtaining this new optimal design, the influence of different magnetizations of permanent magnets (PMs), including radial, parallel and halbach magnetization is investigated on the performance of one typical PMSM by using the conformal mapping (CM) method. To reduce the cogging torque even more, the technique of slot opening shift is also implemented on the stator slots of analyzed PMSM without reduction in the main performance, including the air-gap magnetic field, the average torque and back-electromotive force (back-EMF). Findings Finally, an optimal configuration including the Hat-type magnet poles with halbach magnetization on the rotor and shifted slot openings on the stator is obtained through the CM method, which shows the main reduction in cogging torque and the harmonic content of air-gap magnetic field. Practical implications The obtained optimal design is completely practical and is validated by comparing with the corresponding results obtained through finite element method. Originality/value This paper presents a new optimal design for integral slot PMSMs, which can include different design considerations, such as the reduction of cogging torque and the total harmonic distortion of air-gap magnetic field by using the CM method.

scholarly journals Cogging Torque Reduction in Brushless Motors by a Nonlinear Control Technique

Energies ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 2224 ◽  
Author(s):  
Pierpaolo Dini ◽  
Sergio Saponara
Keyword(s):  
Permanent Magnet ◽  
Electric Drive ◽  
Feedback Linearization ◽  
Permanent Magnets ◽  
Position Control ◽  
Angular Position ◽  
Control Technique ◽  
Electrical Machine ◽  
Brushless Motors ◽  
Cogging Torque

This work addresses the problem of mitigating the effects of the cogging torque in permanent magnet synchronous motors, particularly brushless motors, which is a main issue in precision electric drive applications. In this work, a method for mitigating the effects of the cogging torque is proposed, based on the use of a nonlinear automatic control technique known as feedback linearization that is ideal for underactuated dynamic systems. The aim of this work is to present an alternative to classic solutions based on the physical modification of the electrical machine to try to suppress the natural interaction between the permanent magnets and the teeth of the stator slots. Such modifications of electric machines are often expensive because they require customized procedures, while the proposed method does not require any modification of the electric drive. With respect to other algorithmic-based solutions for cogging torque reduction, the proposed control technique is scalable to different motor parameters, deterministic, and robust, and hence easy to use and verify for safety-critical applications. As an application case example, the work reports the reduction of the oscillations for the angular position control of a permanent magnet synchronous motor vs. classic PI (proportional-integrative) cascaded control. Moreover, the proposed algorithm is suitable to be implemented in low-cost embedded control units.

scholarly journals Low cogging torque design and simplified model-free predictive current control for radial-flux dual three-phase permanent magnet electric machines

2019 ◽  
Vol 11 (12) ◽  
pp. 168781401989164
Author(s):  
Hsing-Cheng Yu ◽  
Hung-Wei Lai ◽  
Li-Jhen Chen ◽  
Cheng-Kai Lin
Keyword(s):  
Permanent Magnet ◽  
Control Method ◽  
Torque Ripple ◽  
Electric Machines ◽  
Current Control ◽  
Simplified Model ◽  
Cogging Torque ◽  
Model Free ◽  
Radial Flux ◽  
Three Phase

This study presents two improved designs of eccentric-shaped permanent magnets and teeth-shaped stators in radial-flux dual three-phase permanent magnet electric machines to reduce cogging torque and torque ripple. The finite element analysis (ANSYS Electromagnetics) has been adopted in simulation, and real radial-flux dual three-phase permanent magnet electric machines have been fabricated in experiment to verify the study. Using the radial-flux dual three-phase permanent magnet electric machines in electric machine systems can improve the reliability and obtain higher output torque. In electrical drives and control, a simplified model-free predictive current control method has been proposed and implemented to drive the radial-flux dual three-phase permanent magnet electric machines, and the control law has been achieved by a TMS320F28377S microcontroller of Texas Instruments. The simplified model-free predictive current control method is senseless to parameter variations and back electromotive force of the permanent magnet electric machines, and only needs current sensors to detect six-phase current. The optimal one has been chosen by 14 various switching modes, which has the minimum cost function, and then the converter can be directly driven and controlled in the next sampling period. The features of the simplified model-free predictive current control method can reduce the algorithm calculation and avoid the defect of conventional model-based predictive current control scheme. A proportional-integral speed controller has also been designed to achieve the speed response of the fixed-speed tracking effect. Finally, the feasibility and effectiveness of the proposed simplified model-free predictive current control method for the dual three-phase permanent magnet electric machines can be verified in the experimental and quantitative results.

scholarly journals Hybrid excited claw pole generator with skewed and non-skewed permanent magnets

Open Physics ◽  
2017 ◽  
Vol 15 (1) ◽  
pp. 902-906 ◽  
Author(s):  
Marcin Wardach
Keyword(s):  
Magnetic Field ◽  
Permanent Magnets ◽  
Excitation Control ◽  
Simulation Studies ◽  
Cogging Torque ◽  
Simulation Results

AbstractThis article contains simulation results of the Hybrid Excited Claw Pole Generator with skewed and non-skewed permanent magnets on rotor. The experimental machine has claw poles on two rotor sections, between which an excitation control coil is located. The novelty of this machine is existence of non-skewed permanent magnets on claws of one part of the rotor and skewed permanent magnets on the second one. The paper presents the construction of the machine and analysis of the influence of the PM skewing on the cogging torque and back-emf. Simulation studies enabled the determination of the cogging torque and the back-emf rms for both: the strengthening and the weakening of magnetic field. The influence of the magnets skewing on the cogging torque and the back-emf rms have also been analyzed.

Reliability Analysis of Door Magnetic Switch under Different Permanent Magnetic Distribution

2012 ◽  
Vol 239-240 ◽  
pp. 328-331
Author(s):  
Xin Hua Yi ◽  
Xiao Min Cheng ◽  
Min Jun Wang
Keyword(s):  
Mathematical Model ◽  
Permanent Magnet ◽  
Reliability Analysis ◽  
Permanent Magnets ◽  
Simulation Method ◽  
Ansys Software ◽  
Reed Switch ◽  
Magnetic Switch ◽  
Magnetic Adsorption ◽  
Simulation Results

In order to improve the reliability and safety of door magnetic switch, a mathematical model of three reed switches was designed to satisfy this requirement under different permanent magnetic distribution. To obtain the same magnetic adsorption force for the magnetic reed switch, this paper uses a simulation method based on ANSYS software to mainly analyze the different distribution of three permanent magnets how to affect the adsorption force of door magnetic switch. The simulation results demonstrate that the adsorption force is different for different layout of permanent magnet and help to obtain the installing position of the reed switch and to improve the reliability.

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