Influence of unequal stator tooth width on the performance of outer-rotor permanent magnet machines

Open Physics ◽  
2020 ◽  
Vol 18 (1) ◽  
pp. 432-438
Author(s):  
Aimeng Wang ◽  
Dashuang Li

AbstractOuter-rotor permanent magnet machines for low-speed and high-torque applications have been used due to their high moment of inertia and torque density. In this paper, the 12-slot/10-pole outer-rotor fractional-slot permanent magnet machine model is established by finite element analysis, the influence of unequal stator tooth width and tooth tip width is investigated for the PM machine, and five different schemes of stator tooth and tip width are designed and analyzed. Detailed comparisons of the performance characteristics of the machines are presented including important issues such as output torque, magnetic field distribution, and tooth flux density. It is shown that the torque density and cogging torque and efficiency can be effectively improved by choosing reasonable tooth and tip width, which lays a foundation for further optimum design and efficiency improvement of the machine.

Author(s):  
Mansouri Ali ◽  
Msaddek Hejra ◽  
Trabelsi Hafedh

<table border="1" cellspacing="0" cellpadding="0" width="593"><tbody><tr><td width="387" valign="top"><p>In recent years, permanent magnet machines have become a common choice in many industrial applications. Therefore, several structures have been developed, and the choice of a topology designed for a specified application requires the knowledge of the advantages and disadvantages of different topologies. The present work deals with the evaluation of the performances of different radial flux surface-mounted permanent magnet motors designed for an electric vehicle motor application. The objective of this survey is to show the effect of the rotor position (inner or outer) and the magnets segmentation on the machine output torque and iron losses. In this context, four machines with: (i) inner rotor, (ii) inner rotor segmented magnets, (iii) outer rotor and (iv) outer rotor segmented magnets have been designed and studied. All these machines have the same geometrical dimensions and current loading. The main idea is to develop a machine with smoothness torque, lower torque ondulation, lower iron losses, and which is mechanically robust. Firstly, the output torque of the different structure is computed. Secondly, by means of an improved analytical model coupled with 2 dimensional transient finite element analysis (FEA), the machines iron losses are predicted.</p></td></tr></tbody></table>


Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3639
Author(s):  
Rundong Huang ◽  
Chunhua Liu ◽  
Zaixin Song ◽  
Hang Zhao

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.


Energies ◽  
2019 ◽  
Vol 12 (7) ◽  
pp. 1238 ◽  
Author(s):  
Dong Yu ◽  
Xiaoyan Huang ◽  
Lijian Wu ◽  
Youtong Fang

This paper presents a novel outer rotor permanent-magnet vernier machine (PMVM) for in-wheel direct-drive application. The overhang structures of the rotor and flux modulation pole (FMP) are introduced. The soft magnetic composite (SMC) was adopted in the FMP overhang to allow more axial flux. The 3-D finite element analysis (FEA) was carried out to prove that the proposed machine can effectively utilize the end winding space to enhance the air-gap flux density. Hence the PMVM can offer 27.3% and 14.5% higher torque density than the conventional machine with no overhang structure and the machine with only rotor overhang structure, respectively. Nevertheless, the efficiency of the proposed machine is slightly lower than the conventional ones due to the extra losses from the overhang structures.


2018 ◽  
Vol 159 ◽  
pp. 02003
Author(s):  
Aravind CV ◽  
Ramani Kannan ◽  
Heng Jing Lei ◽  
Joga Dharma Setiawan

Hybrid vehicles require high torque for propel, hence permanent Magnet machines are highly suiting for the improvement in the torque density. The paper focus on designing built-in interior permanent magnet (IPM) synchronous machine for hybrid electric drive. With the permanent magnet switched from rotor to stator and the characteristics over a wide range of speed operation is studied. The results obtained though performance analysis shows that at 130 rpm high torque with power peaking at around 900 rpm. Both the inner and outer machine are studied using numerical study tool for performance analysis for the application mentioned above. The inner magnet rotor design has provide a better magnetic flux flow due to the larger flux linkage between the permanent magnet and stator pole. Both type of machines are evaluated for torque where the machine with inner magnet provide a higher torque density of 4.94% as compared to the outer magnet machines.


Author(s):  
Hejra Msaddek ◽  
Ali Mansouri ◽  
Trabelsi Hafedh

The objective of this work is to find the optimal geometric parameters for the design of permanent magnet synchronous machines (PMSM) with inversed structure (outer rotor) for electric vehicles applications. Firstly, the machine model is presented with a special attention given to the calculation of the mass and engine efficiency. A multi objective optimization based on the genetic algorithm is then implemented. It will determine the parameters values that optimize the chosen criteria while respecting the specifications: to minimizing the total mass and maximizing the machine efficiency. Finally, 2D steady-state finite element analysis is used for to verify the results given by the optimization method.


Energies ◽  
2018 ◽  
Vol 11 (8) ◽  
pp. 2141 ◽  
Author(s):  
Yuqing Yao ◽  
Chunhua Liu ◽  
Christopher H.T. Lee

Multiphase machines have some distinct merits, including the high power density, high torque density, high efficiency and low torque ripple, etc. which can be beneficial for many industrial applications. This paper presents four different types of six-phase outer-rotor permanent-magnet (PM) brushless machines for electric vehicles (EVs), which include the inserted PM (IPM) type, surface PM (SPM) type, PM flux-switching (PMFS) type, and PM vernier (PMV) type. First, the design criteria and operation principle are compared and discussed. Then, their key characteristics are addressed and analyzed by using the finite element method (FEM). The results show that the PMV type is quite suitable for the direct-drive application for EVs with its high torque density and efficiency. Also, the IPM type is suitable for the indirect-drive application for EVs with its high power density and efficiency.


2015 ◽  
Vol 12 (2) ◽  
pp. 129-143
Author(s):  
Ali Alaeddini ◽  
Ahmad Darabi ◽  
Hamed Tahanian

This paper presents the influence of several structural factors and parameters involved in the design of Claw Pole Transvers Flux Permanent Magnet Machines (TFPMs) on their internal voltage. Knowing the influence of each factor is very important for an effective process of design and optimization for these machines. In this paper by using the complete design algorithm of Claw Pole TFPM, only one parameter is changed at a time and its influence on the internal voltage is analyzed. Output torque is also studied, because the internal voltage has effect on both the average and the ripple of output torque. The most important factors and parameters which are considered are: 1) number of poles; 2) length of air gap; 3) ratio of magnet arc to flux concentrator arc in each pole of rotor; 4) shape of pole shoe of stator and 5) area of rotor pole covered by stator pole. Due to geometrical complexities of TFPMs, analytical methods fail to describe the behavior of these machines. For this reason, in this paper finite element analysis is used both in the design and analysis of TFPMs.


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