Torque Ripple Minimization of PM-assisted Synchronous Reluctance Machines via Asymmetric Rotor Poles

Author(s):  
Simone Ferrari ◽  
Eric Armando ◽  
Gianmario Pellegrino
2021 ◽  
Vol 67 (3) ◽  
pp. 327-338
Author(s):  
Yixiang Xu ◽  
Chong Di ◽  
Xiaohua Bao ◽  
Dongying Xu

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.


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

2016 ◽  
Vol 65 (4) ◽  
pp. 685-701 ◽  
Author(s):  
Piotr Bogusz ◽  
Mariusz Korkosz ◽  
Jan Prokop

Abstract In the paper, the modified (compared to the classical asymmetric half-bridge) converter for a switched reluctance machine with an asymmetric rotor magnetic circuit was analysed. An analysis for two various structures of switched reluctance motors was conducted. The rotor shaping was used to obtain required start-up torque or/and to obtain less electromagnetic torque ripple. The discussed converter gives a possibility to turn a phase off much later while reduced time of a current flows in a negative slope of inductance. The results of the research in the form of waveforms of currents, voltages and electromagnetic torque were presented. Conclusions were formulated concerning the comparison of the characteristics of SRM supplied by the classic converter and by the one supplied by the analysed converter.


Author(s):  
Ahlam Luaibi Shuraiji ◽  
M.M.J. Al-ani

<p>Flux-switching permanent magnet (FSPM) machine with high temperature superconductors (HTS) bulks located between the rotor poles to eliminate the flux leakage in the rotor, termed as (HTS-FSPM) machine has been proposed in this paper. Using genetic algorithm, the HTS and the conventional FSPM machines having the same size constraints and load conditions have been globally optimized for max. aveage torque. To highlight the advantages of the HTS-FSPM machine, a performance comparison between the conventional and HTS-FSPM machines has been presented. It is found that the HTS-FSPM machine can increase the torque by 27%, however, this comes with the expense of higher torque ripple and power losses.  </p>


2017 ◽  
Vol 22 (2) ◽  
pp. 266-274
Author(s):  
Yong-Suk Hwang ◽  
Myung-Hwan Yoon ◽  
Jin-Cheol Park ◽  
Jung-Pyo Hong

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

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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