scholarly journals Performance optimization of permanent magnet synchronous motor by cogging torque reduction

2019 ◽  
Vol 70 (3) ◽  
pp. 218-226 ◽  
Author(s):  
Vasilija Sarac
Keyword(s):  
Permanent Magnet ◽  
Performance Optimization ◽  
High Speed ◽  
Permanent Magnets ◽  
Permanent Magnet Synchronous Motor ◽  
Permanent Magnet Synchronous Motors ◽  
Cogging Torque ◽  
Motor Operation ◽  
Flux Density Distribution ◽  
Starting Model

Abstract The development of the robotics and the automation and the need for the motors that can work in the applications that require high speed, precision and increased efficiency have led to the increased use of permanent magnet synchronous motors and their continuous development in terms of improving their performance. Cogging torque is one of the features of these types of the motors that deteriorate motor performance especially at low speeds. Therefore, in this paper the method of genetic algorithms (GA) is applied as an optimization tool, for minimizing the cogging torque without changing the other important operating parameters like output power, torque or current. Even more, the optimized motor model has improved efficiency compared to the starting model and has the decreased weight of the permanent magnets. The optimization is done by changing the rotor design in terms of the magnet thickness, pole span and shape of the magnets. Finite elements (FE) models of the optimized and the basic motor were derived and from them the flux density distribution in the motor cross section and in the air gap was calculated. In addition, the improvement of the motor operation is observed from the torque characteristics calculated by the FE models.

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.

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 Measurement of the PMSM Shaft Position with An Absolute Encoder

Electronics ◽  
2019 ◽  
Vol 8 (11) ◽  
pp. 1229
Author(s):  
Tomasz Rudnicki
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Permanent Magnet Synchronous Motor ◽  
Correction Method ◽  
Synchronous Motor ◽  
Motor Speed ◽  
Motor Shaft ◽  
Adaptive Correction ◽  
Absolute Encoder ◽  
Motor Operation

The most critical aspect of assessing a permanent magnet synchronous motor is the problem of correctly measuring the position of the synchronous motor shaft. The purpose of this article was to show the effects of employing an absolute encoder to control a synchronous motor with permanent magnets while encountering disturbances. This problem is often overlooked, but it appears from time to time. The correct measurement of the shaft position eliminates improper motor operation characterized by jerking. The article showed that despite momentary erroneous readings of the shaft’s position, it was still possible to control the permanent magnet synchronous motor (PMSM). This also allows for correct measurement of the motor speed. This paper originally proposed an adaptive correction method for a rotary encoder.

scholarly journals Towards an improved energy efficiency of the interior permanent magnet synchronous motor drives

2014 ◽  
Vol 11 (2) ◽  
pp. 257-268 ◽  
Author(s):  
Marko Gecic ◽  
Darko Marcetic ◽  
Veran Vasic ◽  
Igor Krcmar ◽  
Petar Matic
Keyword(s):  
Energy Efficiency ◽  
Permanent Magnet ◽  
High Speed ◽  
Permanent Magnet Synchronous Motor ◽  
Motor Drives ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
Stator Current ◽  
Interior Permanent Magnet ◽  
Efficiency Increase

This paper investigates the possibility of energy efficiency increase in the drives with high speed permanent magnet synchronous motors. The losses are decreased by the proposed procedure, i.e. proper allocation of the available stator current capacity to the direct and quadrature current components. The approach provides increased energy efficiency by varying the ratio between copper and iron losses.

H? Observer Based Sensor-less Control Strategy for Interior Permanent Magnet Synchronous Motor

2011 ◽  
Vol 12 (3) ◽  
Author(s):  
Naomitsu Urasaki ◽  
Abdul Motin Howlader ◽  
Atsushi Yona ◽  
Tomonobu Senjyu ◽  
Ahmed Y. Saber
Keyword(s):  
Control System ◽  
Vector Control ◽  
Permanent Magnet ◽  
High Speed ◽  
Permanent Magnet Synchronous Motor ◽  
Estimation Accuracy ◽  
Voltage Source ◽  
Permanent Magnet Synchronous Motors ◽  
Flux Observer ◽  
Vector Control System

Nowadays a sensor-less vector control system for a motor drive becomes promising to avoid a position sensor. A back electro-motive-force or flux observer is used for sensor-less drive of permanent magnet synchronous motors from middle to high speed range. Thus, the estimation accuracy of the observer influences sensor-less drive performance. This paper proposes a sensor-less vector control system using the H? flux observer in which the observer gain is designed based on the H? control theory. This observer is insensitive to high frequency disturbances such as voltage disturbance due to non-linearity of PWM voltage source inverter, measurement noise of current sensors, and modeling errors. So, the total performance of a sensor-less control system is enhanced. The detailed configuration of the H? flux observer is described in this paper. Simulation results are compared with the conventional full-order flux observer-based sensor-less system.

Influence of unbalanced magnetic force on shaft deflection in permanent magnet synchronous motor with fractional slot concentrated windings

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1461-1468
Author(s):  
Ting Dong ◽  
Juyan Huang ◽  
Bing Peng ◽  
Ling Jian
Keyword(s):  
Permanent Magnet ◽  
Magnetic Force ◽  
Permanent Magnet Synchronous Motor ◽  
Operational Reliability ◽  
Topology Structure ◽  
Permanent Magnet Synchronous Motors ◽  
Synchronous Motors ◽  
Shaft Deflection ◽  
Large Length ◽  
Fractional Slot

The calculation accuracy of unbalanced magnetic forces (UMF) is very important to the design of rotor length, because it will effect the shaft deflection. But in some permanent magnet synchronous motors (PMSMs) with fractional slot concentrated windings (FSCW), the UMF caused by asymmetrical stator topology structure is not considered in the existing deflection calculation, which is very fatal for the operational reliability, especially for the PMSMs with the large length-diameter ratio, such as submersible PMSMs. Therefore, the part of UMF in the asymmetrical stator topology structure PMSMs caused by the choice of pole-slot combinations is analysized in this paper, and a more accurate rotor deflection calculation method is also proposed.

scholarly journals Research on the Non-Magnetic Conductor of a PMSM Based on the Principle of Variable Exciting Magnetic Reluctance

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 318
Author(s):  
Chunyan Li ◽  
Fei Guo ◽  
Baoquan Kou ◽  
Tao Meng
Keyword(s):  
Permanent Magnet ◽  
Electromagnetic Force ◽  
Electromotive Force ◽  
Permanent Magnets ◽  
Permanent Magnet Synchronous Motor ◽  
Synchronous Motor ◽  
Magnetic Conductor ◽  
Critical Speeds ◽  
Motor Structure ◽  
Test Result

A permanent magnet synchronous motor (PMSM) based on the principle of variable exciting magnetic reluctance (VMRPMSM) is presented. The motor is equipped with symmetrical non-magnetic conductors on both sides of the tangential magnetized permanent magnets (PMs). By placing the non-magnetic conductor (NMC), the magnetic reluctance in the exciting circuit is adjusted, and the flux weakening (FW) of the motor is realized. Hence, the NMC is studied comprehensively. On the basis of introducing the motor structure, the FW principle of this PMSM is described. The shape of the NMC is determined by analyzing and calculating the electromagnetic force (EF) acting on the PMs. We calculate the magnetic reluctance of the NMC and research on the effects of the NMC on electromagnetic force, d-axis and q-axis inductance and FW performance. The critical speeds from the test of the no-load back electromotive force (EMF) verify the correctness of the NMC design. The analysis is corresponding to the test result which lays the foundation of design for this kind of new PMSM.

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