• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.2
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• pp.71-77
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• 2012

The cogging torque is important to the cut-in wind speed. And, it causes the acoustic noise and the vibration on the machine. This paper presents a 3D FEA(Finite Element Analysis) to evaluate the effect of magnet skew and stator displacement on cogging torque reduction, for double core AFPM(Axial Flux Permanent Magnet) generator. As a result, the magnet skew and the stator side displacement are proved excellent techniques to reduce the cogging torque.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.10-17
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• 2012

This paper presents an improved iron loss model, for the computation of the no load iron loss in the stator core of the in-wheel permanent magnet synchronous motors (PMSM), for the cases of with and without stator skew. 2-D analytical model is used for the computation of tooth and yoke flux densities of the in-wheel PMSM. The no load iron loss computed by the improved iron loss model, for the cases of with and without skew is compared with the finite element method (FEM) and the results show good consistency.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.10
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• pp.1403-1407
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• 2013

This paper presents the method to calculate the motor parameters considering skew in EPS Interior Permanent Magnet Synchronous Motor (IPMSM). The skew is applied to stator or rotor by general technology used for design of reducing noise and vibration in motor. The characteristics analysis of motor including the skew is mostly used by 3D Finite Element Analysis (FEA), though, this analysis is a very time-consuming to perform. Besides, The reliability lacks due to the considerable change of motor characteristics according to the number of elements in 3D FEA. However, analysis time and effort can be saved by characteristic analysis considering skew using 2D FEA. Therefore, in this paper, a quick and accurate method for the calculations of motor parameters considering skew is suggested. The proposed method is verified by the comparison of calculated and experimental results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2004.03a
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• pp.472-478
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• 2004

This paper describes the characteristics of the unsteady pressure on the stator surface induced by rotor viscous wakes. The primary object of this study is to investigate the effects of axial spacing between the rotor and the stator and three-dimensional vane geometries such as stator sweep and stator lean on the unsteady pressure fluctuations on the stator vane. To predict these fluctuations, unsteady three-dimensional Navier-Stokes analyses are performed. Furthermore, a three-dimensional analytical method using unsteady lifting-surface theory is also used to elucidate the mechanism of interaction of passing rotor wakes with downstream stator. Five different fan configurations with three sets of stator geometries, which are three radial stator configurations with different axial spacing, the swept stator and the swept and leaned stator, are used for this study. It is found that, in axial spacing between rotor and stator, the effect of radial phase skew of incoming rotor wake is important for the reduction of the induced unsteady pressure in addition to the rotor wake decay. It is also shown that incorporation of stator sweep and lean is effective to reduce this unsteady pressure.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.58-62
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• 1990

Air gap flux density is obtained strictly from air gap permeance and MMF distribution using the design parameter of BLDCM when the stator slot is considered. Then the theoretical equations representing the cogging torque and BEMF are proposed. The effect of skew is described analytically, and skew effect on air gap permeance and MMF is studied. Consequently we verified analytically that skew of slots and magnets influenced on the reduction of the cogging torque and BEMF ripple, and the shape of BEMF.

• Proceedings of the KIEE Conference
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• 1989.11a
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• pp.10-14
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• 1989

This paper shows an experimental study of home appliance motor noise, also represents some relations between skew-types and skew-angles. Frequency analysis was made for stator and rotor harmonic fluxes. making use of searching coils. Besides electrical analysis, mechanical noise trans mission analysis are studied to lee how they affected on the noise of the motor. Finally, we proved the noise sources of the motor using sound intensity method.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.7
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• pp.643-655
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• 1991

The analysis method on air gap permeance distribution, air gap MMF distribution, air gap flux density distribution, cogging torque and BEMF about the skewed stator slots or the skewed rotor magnet segments for BLDCM, respectively, is studied as a function of the skew ratio. The proposed method describes the differences between the skewed stator slots and teh skewed rotor magnet segments for the air gap permeance distribution, air gap MMF distribution and air gap flux density distribution. The reliability of the method is also confirmed by the waveform of the cogging torque and BEMF through experiments. And the result shows that the effects on the cogging torque and BEMF due to the skewed stator slots or the skewed rotor magnet segments are the same. In case of the skewed stator slots, the effects of the variations of the winding resistance and inductance are also studied.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.55 no.3
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• pp.123-130
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• 2006

This paper presents characteristics analysis of skewed Synchronous Reluctance Motor using equivalent magnetic circuit and compares with the result of Finite Element Method. Torque ripple must be reduced, because it is producing noise and vibration. There is many kinds of method to reduce torque ripple, but generally we apply skewing stator or rotor. The 2D Finite Element Method(FEM) or 3D FEM is used to analyze the motor, since skew influence the average torque in the motor. However, the FEM takes much time in spite of the advanced computer and numerical technique. This paper will analyze characteristics of skewed synchronous reluctance motor using equivalent magnetic circuit.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.49 no.12
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• pp.797-806
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• 2000

In this paper, the torque characteristics and the bar loss distribution are analyzed when a general cage induction motor with skewed slots is fed by a 6-step inverter. For the electromagnetic analysis, time-stepping finite element method is used. And the multi-slice technique and sliding surface technique are respectively utilized to consider the skew effect and the rotation of the rotor. As a result, the effects of skewed rotor bar and the inverter output voltage on the characteristics of the torque and bar loss in the rotor are investigated. The simulation results are verified by measurement of flux density distribution axially in the stator teeth.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.19-21
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• 1998

The problem in improving the positioning precision of a Permanent Magnet Linear Synchronous Motor (PMLSM) is the detent force caused by the interaction of the magnets with the teeth of stator. This paper presents 3-Dimensional Equivalent Magnetic Circuit Network Method (3-D EMCN) for the analysis of PMLSM. 3-D EMCN is a numerical analysis method which supplements magnetic equivalent circuit by using numerical technique. We analyzed the fields and forces of PMLSM in case of skewed magnet and axially segmented magnet construction.