• 전기학회논문지
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• 제59권5호
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• pp.897-903
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• 2010

This paper presents a response surface method(RSM) with Latin Hypercube Sampling strategy, which is employed to optimize a magnet pole shape of large scale BLDC motor to minimize the cogging torque. The proposed LHS algorithm consists of the multi-objective Pareto optimization and (1+1) evolution strategy. The algorithm is compared with the uniform sampling point method in view points of computing time and convergence. In order to verify the developed algorithm, a 6 MW BLDC motor is simulated with 4 design parameters (arc length and 3 variables for magnet) and 4 constraints for minimizing of the cogging torque. The optimization procedure has two stages; the fist is to optimize the arc length of the PM and the second is to optimize the magnet pole shape by using the proposed hybrid algorithm. At the 3rd iteration, an optimal point is obtained, and the cogging torque of the optimized shape is converged to about 14% of the initial one. It means that 3 iterations aregood enough to obtain the optimal design parameters in the program.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 추계학술대회 논문집
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• pp.423-426
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• 2009

POSTECH Graduate School of Wind Energy is trying to upgrade the PMSG used for Unison U50 to 900 kW class. Intensive optimization efforts are carried out the reduce the axial size and total weight of the generator while increasing the rated output to 900 kW. The generator features 3.32m stator inner radius, 671mm stator length, 84 pole, 25 rated rpm and 31.6kN/$m^2$ shear force density. To reduce the gross weight, the stronger magnetic material is applied with optimal magnet size resulting lowest cogging torque. Also, instead of stator skewing the stator, the magnet position along the circumference is optimized to further reduce the cogging torque. This scheme eliminates the stator skewing procedure and may enhance the productivity. This method also reduces the total harmonic distortion. In this report, upgrade method, no-load line to line voltage and phase voltage, cogging torque, loss calculations and thermal analysis are presented.

• 전기학회논문지
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• 제65권3호
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• pp.428-438
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• 2016

This paper shows the design of the 100 kW IPMSG for small hydraulic power generator. The high-efficient generator, method of the dual layer interior permanent magnet was studied to improve the method of the single layer interior permanent magnet, which is mostly used. Analysis of magnet arrangement and cogging torque was done by FEM. According to structure analysis of dual layer interior permanent magnet, the amount of usage of the permanent magnet was reduced and cogging torque was decreased as well. With these successful results, the high-efficient generator design was accomplished. Based on the results of the structure analysis, the test product was designed and manufactured. And the design values and performance outputs were compared and verified with success. Also, the economic feasibility was conducted based on the electric power generated from the test product installed at the site. By the B/C analysis, in case that only SMP was analyzed, B/C ratio was 1.24 at the discount ratio of 5.5%, which considered to be economically feasible. The study is expected to be used for the application of developing large scale high-efficient interior permanent magnet synchronous generator.

• 전기학회논문지
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• 제65권11호
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• pp.1806-1812
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• 2016

We propose an interior permanent magnet syhchronous motor (IPMSM) with arc-shape ferrite permanent magnets (PMs) as a substitute for the rare-earth permanent magnet, and determine its optimal design through parametric study. First, we use 2D finite element analysis to analyze 4-poles and 6-slots initial model according to performance requirements and design parameters. The current angle of the maximum average torque considered in the analysis is different compared with the current angle of the minimum torque ripple. Thus, the parametric study for optimal rotor design is performed by varying the thickness and the offset radius of the PMs according to current angle. In particular, a narrow bridge is required in conventional IPMSM for reducing flux leakage; however, the increase in cogging torque in the analysis model saturates the narrow bridge (large offset radius). Therefore, we suggest an appropriate shape considering limiting conditions such as DC link voltage, average torque, torque ripple, and cogging torque taking into account performance requirements.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.170-172
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• 2006

This paper proposes a design method by varying rotor pole shape to reduce cogging torque, torque ripple and harmonics of back emf in Spoke type brushless DC(BLDC) motor. In the process of design and analysis, Response surface method(RSM) and finite-element method(FEM) are employed to get the rotor geometry and verify the results of new pole shape.

• Journal of Electrical Engineering and Technology
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• 제7권5호
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• pp.753-758
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• 2012

This paper deals with the analysis of vibration and noise sources in a modular-type SPM fractional-slot motor. To reduce cogging torque, torque ripple and unequal radial force, which are the main causes of the electromagnetic vibration, the optimal shape of notch and magnet are designed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.895_896
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• 2009

this paper presents a rotor shape optimization of interior type permanent magnet (IPM) motor for vibration minimization. the vibration of permanent magnet motor is generated by cogging torque, radial force and commutation torque ripple which are electromagnetic source of vibration. In order to minimize the vibration, the optimal notches are put on the rotor pole face and the arc type pole face is applied. The variations of cogging torque and radial force of each model vibration frequency are computation by finite element method (FEM) and the validity of the analysis and rotor shape design is confirmed by vibration experiments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.65-67
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• 2007

This paper proposes a novel flux barrier in q-axis of rotor in IPM type BLDC motor, The proposed flux barrier can reduce cogging torqeu and diminisg torque ripple by sinusoidal waveform distribution of flux generated in the permanent magnet. To determine the optimal shape of the novel flux barrier, we also propose a modified Taguchi method which considering multiple quality characteristics, such as cogging torque, average torque, and efficiency. The proposed design and method were analyzed by using the 2D finite element method (FEM). Results of the proposed model were compared with initial model.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.669-670
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• 2015

In this paper, rotor design modification of a novel proposed machine termed the Axial Flux Doubly Fed Reluctance Machine (AF-BDFRM) is studied. The main potential advantage of AF-BDFRM is that it has larger torque and power density compared to radial flux-BDFRM. However, with the general rotor pole shape, this machine output back EMF has high THD % and high cogging torque. This paper studies the rotor design modification in the proposed AF-BDFRM to reduce the THD % in inducedd back EMF and cogging torque. Also the transient 3D finite element analysis (FEA) optimization of initial design is presented.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.123-124
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• 2015

본 논문에서는 동기전동기(PMSM: Permanent Magnet Synchronous Motor)의 고정자 형상 변화를 통한 코깅토크(Cogging Torque)와 토크리플(Torque Ripple)저감에 대해 다루고자 한다. 고정자의 치의 두께와 길이에 변화를 주면서 FEM(Finite Elements Method)기반의 성능분석을 실시하여 각 형태에 대한 평균토크, 토크리플, 코깅토크를 분석, 비교해보았다.