Multi-material topology optimization of permanent magnet synchronous motors

Author(s):  
Sohyun Park ◽  
Jaejoon Lee ◽  
Jaewook Lee

This paper presents a multi-material topology optimization for the design of permanent magnet synchronous motors (PMSMs). Specifically, structural shapes of permanent magnet (PM) and iron core in a PMSM rotor are simultaneously designed together with the orientation of PM magnetization. For a co-design of PM and iron core, relative permeability and residual magnetic flux density are interpolated by the three-field density approach based on the Helmholtz filtering and regularized Heaviside step function. Here, the Helmholtz filtering aims to attain smooth border in design results, and the Heaviside function enables us to acquire a clear border (i.e. zero-one design) without intermediate densities. The optimization goal is set as maximizing the average torque of PMSMs. The average torque is calculated by Maxwell stress tensor (MST) method considering a maximum torque per ampere (MTPA) control. To validate the effectiveness of the proposed multi-material topology optimization approach, a PMSM rotor with 4 poles and 12 slots is designed. In addition, design results at various settings of input current amplitude and PM strength are compared and discussed. When the input current is stronger than the PM strength, rotor PM and iron core are designed for utilizing both PM and reluctance torque components like V-shape interior PMSMs. On the other hand, in the case of stronger PM strength, PM is designed near the air-gap, which utilizes only PM torque component like surface PMSMs.

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1413
Author(s):  
Hyungkwan Jang ◽  
Hyunwoo Kim ◽  
Huai-Cong Liu ◽  
Ho-Joon Lee ◽  
Ju Lee

Owing to the development of electric vehicles (EVs), research and development are underway to minimize torque ripple in relation to vibration and noise in EV motors. Although there are various ways to reduce torque ripple, this study analyzes the torque ripple, cogging torque, total harmonic distortion (THD), and magnetic flux density distribution for the three rotor shapes of interior permanent magnet synchronous motors, which are widely employed in EVs. To reduce the torque ripple while retaining the required average torque, the barrier shape is optimized, and wedge skew is applied. First, regarding the rotor barrier shape, torque ripple is primarily reduced by designing the rotor barrier shape with the response surface method, which is an experimental design method. Additionally, the wedge skew shape considering the bidirectional rotation and fabrication was applied to the stator shoe as a step and analyzed using three-dimensional finite element analysis. When designing the wedge skew, the layer subdivision according to the axial length, wedge skew diameter, and wedge skew position was analyzed and improved. The torque ripple reduction method in this paper can be applied not only to motors for EVs or Hybrid EVs (HEVs) but also all types of permanent magnet synchronous motors.


2020 ◽  
Vol 64 (1-4) ◽  
pp. 1461-1468
Author(s):  
Ting Dong ◽  
Juyan Huang ◽  
Bing Peng ◽  
Ling Jian

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.


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