Design and analysis of a PM-assisted brushless WRSM for improving torque characteristics

2020 ◽  
Vol 64 (1-4) ◽  
pp. 1127-1134
Author(s):  
Ghulam Jawad Sirewal ◽  
Muhammad Ayub ◽  
Byung-il Kwon

This paper proposes a permanent magnet assisted brushless wound rotor synchronous machine (PMa–BL–WRSM) design. The proposed machine has the advantage of a high starting torque compared to existing BL–WRSM topologies. Additionally, the average torque increases and the torque ripple is reduced when the permanent magnet assisted machine structure is used. PMa–BL–WRSM operates on the principle of brushless excitation using zero-sequence, third-harmonic current generation in the stator windings. The third harmonic component is harnessed to induce a voltage in the harmonic winding which is mounted on the rotor. As there is no flux generated from filed winding in the starting, the starting torque of the machine is also zero. To overcome the problem, permanent magnets (PMs) are inserted in each field tooth to provide the initial source of flux on the rotor. Finite element analysis is performed with the PM–BL–WRSM, and the elicited results are compared with the basic machine structure. The proposed machine operation is verified using 2-D finite element analyses using the ANSYS Maxwell analysis tool.

2020 ◽  
Vol 35 (9) ◽  
pp. 1012-1021
Author(s):  
Xianming Deng ◽  
Ran Li ◽  
Lei Hao ◽  
Ankang Zhang ◽  
Junhong Zhou

In this paper, a permanent magnet assisted synchronous reluctance machine (PMASRM) with optimized permanent magnet width and asymmetric rotor structure is proposed. A typical PMASRM is selected as the reference motor (Pre-optimized PMASRM). In order to reduce the large torque ripple of conventional PMASRM, an optimization method to design the permanent magnet width is investigated and the Optimized Magnet-width PMASRM is proposed. On this basis, an asymmetric flux barriers structure is proposed to further reduce the torque ripple. Some electromagnetic characteristics including air-gap flux density, no-load back EMF and motor efficiency are examined by Finite Element Analysis (FEA). The simulation results show that the proposed PMASRM can not only decrease the harmonic component of no-load back EMF obviously, but also reduce the torque ripple in steady-state operation, which proves the rationality of the motor structure.


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.


2016 ◽  
Vol 78 (9) ◽  
Author(s):  
Izzati Yusri ◽  
Mariam Md Ghazaly ◽  
Esmail Ali Ali Alandoli ◽  
Mohd Fua'ad Rahmat ◽  
Zulkeflee Abdullah ◽  
...  

This paper addresses a rotary motion type of electromagnetic actuator that compares two types of electromagnetic actuators; i.e the Permanent Magnet Switching Flux (PMSF) and the Switching Reluctance (SR) actuator. The Permanent Magnet Switching Flux (PMSF) actuator is the combination of permanent magnets (PM) and the Switching Reluctance (SR) actuator. The force optimizations are accomplished by manipulating the actuator parameters; i.e. (i) the poles ratio of the stator and rotor; (ii) the actuator’s size; (iii) the number of winding turns; and (iv) the air gap thickness between the stator and rotor through Finite Element Analysis Method (FEM) using the ANSYS Maxwell 3D software. The materials implemented in the actuator’s parameters optimizations are readily available materials, especially in Malaysia. The excitation current used in FEM analysis for both actuators was between 0A and 2A with interval of 0.25A. Based on the FEM analyses, the best result was achieved by the Permanent Magnet Switching Flux (PMSF) actuator. The PMSF actuator produced the largest magnetostatic thrust force (4.36kN) once the size is scaled up to 100% with the input current, 2A respectively. The maximum thrust force generated by the Switching Reluctance (SR) actuator was 168.85μN, which is significantly lower in compared to the results of the PMSF actuator. 


Energies ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3887
Author(s):  
Jeong ◽  
Lee ◽  
Hur

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.


2011 ◽  
Vol 179-180 ◽  
pp. 1303-1308
Author(s):  
Guang Hui Wang

In terms of various applications of linear motor, there are different design objectives with varying concerns. In this paper, the objective is to obtain the slot/pole ratio for tubular permanent-magnet linear synchronous motor (TPMLSM). Direct-axis current analysis and finite element technique are utilized to investigate the optimal slot/slot ratio design of the TPMLSM. Based on electrical angle drift of slots between two neighboring permanent magnets, the slot/pole ratio (SPR), one of the key factors in design, is deduced by direct-axis current analysis. In contrast to those experiment methods, the proposed technique is convenient and swift; moreover it is proven that the method is efficient by 2-D axisymmetic finite element analysis.


Energies ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 384 ◽  
Author(s):  
Hyunwoo Kim ◽  
Yeji Park ◽  
Huai-Cong Liu ◽  
Pil-Wan Han ◽  
Ju Lee

In order to improve the efficiency, a line-start synchronous reluctance motor (LS-SynRM) is studied as an alternative to an induction motor (IM). However, because of the saliency characteristic of SynRM, LS-SynRM have a limited power factor. Therefore, to improve the efficiency and power factor of electric motors, we propose a line-start permanent magnet assistance synchronous reluctance motor (LS-PMA-SynRM) with permanent magnets inserted into LS-SynRM. IM and LS-SynRM are selected as reference models, whose performances are analyzed and compared with that of LS-PMA-SynRM using a finite element analysis. The performance of LS-PMA-SynRM is analyzed considering the position and length of its permanent magnet, as well as its manufacture. The final model of LS-PMA-SynRM is designed for improving the efficiency and power factor of electric motors compared with LS-SynRM. To verify the finite element analysis (FEA) result, the final model is manufactured, experiments are conducted, and the performance of LS-PMA-SynRM is verified.


Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2240
Author(s):  
Sajjad Ahmadi ◽  
Thierry Lubin ◽  
Abolfazl Vahedi ◽  
Nasser Taghavi

This paper presents a multi-objective optimal rotor design for an interior permanent magnet synchronous motor (IPMSM) based on finite element analysis. Due to the importance of torque characteristic in electromagnetic design of IPMSMs, the main efforts of this study are focused on finding a proper trade-off for its torque profile challenges. In this regard, in order to attain high average torque and low torque ripple, the influence of several key factors, such as the permanent magnet (PM) arrangements, PM positions and PM sizes, are examined. Subsequently, according to the outcomes of the performed sensitivity analysis, the appropriate variation interval of the parameters as well as their initial values is determined. Employing such a deterministic optimization algorithm, which does not need large sample points, minimizes the finite element computational cost and leads to accelerate the convergence process. The two-dimensional finite element model (FEM) of an IPMSM is used to perform a sensitivity analysis and establish a multi-objective FEM-based optimization.


2021 ◽  
Vol 11 (5) ◽  
pp. 2159
Author(s):  
Yong-min You ◽  
Keun-young Yoon

The irreversible demagnetization of permanent magnets causes the deterioration of the performance in permanent magnet synchronous motors (PMSMs), which are used for electric vehicles. NdFeB, which is the permanent magnet most commonly used in PMSMs for electric vehicles, is easily demagnetized at high temperatures. Because traction motors for electric vehicles reach high temperatures, and a high current can be instantaneously applied, permanent magnets of PMSM can be easily demagnetized. Therefore, it is important to study the demagnetization phenomenon of PMSMs for electric vehicles. However, since the demagnetization analysis procedure is complicated, previous studies have not been able to perform optimization considering demagnetization characteristics. In this study, we optimized the shape of a PMSM for electric vehicles by considering the demagnetization characteristics of permanent magnets using an automated design of experiments procedure. Using this procedure, a finite element analysis for each experimental point determined by a sampling method can be performed quickly and easily. The multi-objective function minimizes the demagnetization rate and maximizes the average torque, and the constraints are the efficiency and torque ripple. Various metamodels were generated for each of the multi-objective functions and constraints, and the metamodels with the best prediction performance were selected. By applying a multi-objective genetic algorithm, 1902 various optimal solutions were obtained. When the weight rate of the demagnetization rate to the torque was set to 0.1:0.9, the demagnetization rate and average torque were improved by 4.45% and 2.7%, respectively, compared to those of the initial model. The proposed multi-objective optimization method can guide the design of PMSMs for electric vehicles with high reliability and strong demagnetization characteristics.


Sensors ◽  
2020 ◽  
Vol 20 (8) ◽  
pp. 2406 ◽  
Author(s):  
Cezary Jędryczka ◽  
Dawid Danielczyk ◽  
Wojciech Szeląg

This paper deals with the torque ripple minimization method based on the modulation of the phase currents of the permanent-magnet synchronous motor (PMSM) drive. The shape of the supply current waveforms reducing the torque ripple of the machine considered was determined on the basis of finite element analysis (FEA). In the proposed approach, the machine is supplied by a six-leg inverter in order to allow for the injection of zero sequence current harmonics. Two test PMSMs with fractional-slot concentrated windings (FSCW) and surface-mounted permanent magnets (SPMs) have been examined as a case study problem. Wide-range fractional analyses were performed using developed numerical models of the electromagnetic field distribution in the considered machines. The results obtained show that the level of torque ripple in FSCW PMSMs can be effectively reduced by the modulation of the phase currents under the six-leg inverter supply.


2017 ◽  
Vol 54 (1) ◽  
pp. 3-11 ◽  
Author(s):  
O. Kudrjavtsev ◽  
A. Kallaste ◽  
A. Kilk ◽  
T. Vaimann ◽  
S. Orlova

Abstract The paper discusses problems concerning the influence of permanent magnet material characteristics on the low-speed permanent magnet generator losses and output characteristics. The variability of the magnet material and its effect on the output parameters of the machine has been quantified. The characteristics of six different grades of neodymium permanent magnets have been measured and compared to the supplier specification data. The simulations of the generator have been carried out using transient finite element analysis. The results show that magnet materials from different suppliers have different characteristics, which have a significant influence on the generator output parameters, such as efficiency and power factor.


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