• 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.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.505-509
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• 2001

When the spindle is rotated for machining the workpiece, the vibration is generated due to the spindle unbalance. This vibration affects surface finish, dimensional accuracy, tool life, and spindle bearings. To compensate this effect of the spindle unbalance, the spindle system using an EME(electro magnetic exciter)is proposed in this paper. In the proposed spindle system, the vibration due to the spindle unbalance is monitored using vibration sensors and is compensated by electromagnetic attractive forces generated in the EME which are excited by anti-direction forces corresponded with the measured unbalance. Firstly, the spindle system using an EME and control system are constructed to compensate the effect of spindle unbalance in this paper. And then the system is modeled by bond graph to analyze the system. Finally, a controller for vibration compensation due to spindle unbalance is designed and is implemented in real experimental system. As a result, experimental results show this proposed spindle system is very effective to compensate the spindle unbalance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.224-229
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• 2008

With the wide use of mobile phones, a paging signal by a sound transducer acts as an environmental noise on many occasions, thus necessitating an alternative paging signal by a vibration motor. Conventional vibration motors employ three-phase windings with mechanical brushes for commutation. In this paper, a new one-phase brushless and sensorless vibration motor is introduced utilizing digital signal processor chips in cell-phones. For electromagnetic field analysis, two-dimensional modeling can be implemented to determine the back electromotive force using axisymmetric boundary conditions. Geometric design parameters, such as coil pitch and magnet pitch. are considered for performance optimization. Through the experiments, it is shown that the proposed design has the equivalent performance with reduced number of parts, thus enhancing manufacturing productivity and reducing manufacturing cost.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.230-235
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• 2008

With the advent of the telecommunication era, a mobile phone becomes a necessary communication device in modern society. For silent tactile signal, vibration motors have become one of the generic components in most mobile phones. Conventional vibration motors employ three-phase windings with mechanical brushes for commutation. However, mechanical commutation in these prior arts greatly deteriorates its life span, reliability, and productivity due to structural intricacy. This paper introduces a novel design of solenoid-type vibrators using electromagnetic and mechanical analysis. The proposed vibrators have a simpler structure and longer life span by eliminating wear-prone commutation parts in vibration motors.

• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.462-467
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• 2010

This paper presents the rotor shape optimization of an interior type permanent magnet (IPM) motor for a reduction of vibration and Electromagnetic Interference (EMI). The vibration and EMI in permanent magnet motors is generated by cogging torque ripple, radial force and commutation torque ripple. Consequently, in order to improve vibration and EMI, the optimal notches are put on the rotor pole with an arc shape proposed. The variation of vibration frequency due to the cogging torque and radial force of each model is computed by the finite element method (FEM). From the analysis result and experiment, we confirmed the proposed model has remarkably improved the vibration and EMI.

• Journal of Electrical Engineering and Technology
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• 제11권6호
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• pp.1614-1627
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• 2016

The purpose of this paper is to investigate the united Electromagnetic characteristics for the effective monitoring on the static air-gap eccentricity (SAGE) of turbo-generator. Different from other studies, this paper not only studies on the unbalanced magnetic pull (UMP) and the vibration characteristics of the stator and the rotor, but also investigates the harmonic features of the magnetic flux density and the circulating current inside the parallel branches (CCPB). The theoretical calculation, together with the finite-element-method (FEM) simulation and the experiment verification, is taken for a SDF-9 type non-salient generator. It is shown that, when SAGE occurs, apparent double-frequency UMP and vibrations will be produced both on the stator and the rotor, while the CCPB will have an obvious increment at the $1^{st}$ harmonic component. In addition, the amplitude of the magnetic flux density will be of cosine distribution in the circumferential position of the air-gap, while in normal condition it is a constant. Moreover, the pass-band amplitude, together with the $1^{st}$ harmonic of the magnetic flux density, will be enlarged as well. These united electromagnetic characteristics can be used as the diagnosis and monitoring criterion for SAGE.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.486-487
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• 2009

Recently active engine mounting system is developed for improvement of vehicle NVH Problem which is caused by development of high efficient powertrain and lightweight vehicle body. The aims in the development of active engine mounting system is performance confirmation of vehicle to apply active engine mount. In this paper, NVH test was done on test vehicle including active engine mount. And performance of active engine mount is evaluated by controlling active engine mount.

• 한국소음진동공학회논문집
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• 제22권3호
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• pp.208-213
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• 2012

With great advancement of the automobile functions, environmental factors become important performances, especially noise. This paper investigates noise sources of outer rotor type BLDC motor using in the air-conditioner of the automobiles. To this end, this paper is analyzed two viewpoints, structural and electromagnetic causes. Structural analysis is conducted through modal test and analysis. For modal analysis, 3D finite element analysis is carried out using commercial program ansys. Electromagnetic causes are analyzed from local force that is computed by Maxwell stress tensor method. Local force excites structure of motor directly. Finally, correlation analysis is performed to determine effect between noise causes.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2009년도 제40회 하계학술대회
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• pp.853_854
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• 2009

This paper deals with the analysis of noise sources in interior permanent magnet (IPM) motor considering the natural frequencies of stator and electromagnetic forces. In order to analyze the noise generated from the vibration of stator, measured acceleration of stator is compared with calculated acceleration using electromagnetic forces and harmonic analysis.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 추계학술대회 논문집
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• pp.303-306
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• 1997

Magnetic bearings have been adopted to support the rotor by electromagnetic force without mechanical contact and have many advantages. The application of the magnetic bearings have become more and more widespread in recent years. But magnetic bearings require feedback control for stable operation because they are inherently open loop unstable systems. In this study, H infinity controller has been applied for rotor-magnetic bearing system for vibration control. The result showed that H infinity controller has better performance than PID controller through simulations.