• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.401-405
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• 2003

Sound quality is becoming a major concern in optical disc drives (ODD). In order to improve the sound quality of slim type ODDs, we changed lead screw pitch and firmware algorithm in the seek mode. To evaluate the sound quality, the PCM (Paired Comparison Method) was adopted and the result was compared with the time-averaged loudness spectrum. Sound signals were also recorded and modified by increasing or decreasing selected frequency bands to verify their sensitivities to the sound quality. As a result of jury test, preferred frequency bands are associated with the time-averaged loudness spectrum.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.214-219
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• 2003

Recently, the optical disk drive that is thin in thickness has been demanded by the popularization of notebook PC. The device that controls the thickness of a drive is the height of optical pickup. Therefore, researches about this are going on and an asymmetric actuator is the good choice fur this target. However, the actuator of this design has troubles that a subsidiary resonance is likely to be actuated by discord between the center of force and the mass of renter. In this paper, relation between the tracking coil and the subsidiary resonance is analyzed and dynamic characteristics of an actuator are improved by using experiments design and response surface method.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1990년도 춘계학술대회
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• pp.63-65
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• 1990

The main concepts in the design and construction of an motorized wheelchair for loading in the car which is intended to drive a disabled to long distance. The wheelchair is basically a powered and folding, so it is designed to motorized manual wheelchair by modularity method. The wheelchair has been installed with a power motor module, battery module, and drive & control module. The goal of this project is to develop a wheelchair that has multifunction and operated disabled who has variety impairment. So we are currently working.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1988년도 전기.전자공학 학술대회 논문집
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• pp.65-68
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• 1988

In this paper the application of variable structure control with sliding modes for improving the dynamic response and eliminating chattering of DC servo motor drive is presented. Sliding mode control is an effective means to keep a system insensitive to parameter variation and disturbances. In this method the control structure is changed discontinuously to farce the system dynamic to follow a predetermined trajectory. However the discontinuous change in control structure causes the controller input to chatter and gives non-zero steady state error. To overcome this problem, the discontinuous sign function is replaced by a proper continuous function, and presented through experiment.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권11호
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• pp.548-556
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• 2003

Switched reluctance motor(SRM) has simple magnetic structure, and needs simple power electronic driving circuit. It is very useful for wide range adjustable speed drive system. But, SRM drive generates large vibration and acoustic noise because it is commutated individually by step pulse m.m.f of each phase. In the vibration and acoustic noise characteristics. the considerable vibration and noise is induced by radial deforming of stator, so the frequency of dominant vibration and noise is coincident with the frequency of natural frequency of mechanical structure. This radial vibration force is generated by abrupt change of radial magnetic force in the phase commutation region. This paper studied about simple electromagnetic structure of SRM using auxiliary compensating winding for the reduction of noise and vibration. This auxiliary winding is coupled with all phase windings electromagnetically and absorb and transfer magnetic energy variation from phase to other phase. By this interaction of phase windings and compensating winding can reduce abrupt radial force change and vibration and acoustic noise. In this paper the improvement effect is examined by the test of prototype machine.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 F
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• pp.1990-1992
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• 1998

A vector control scheme is widely used in AC drive system in these days. In this country for commercializing the system, it has lots of dependency on advanced foreign technology. Therefore we have developed high-performance vector controlled inverter sytems ourselves for two years whose capacitives are 15kW, 30kW and 45kW. For computation of data in high speed DSP is empolyed and by using a IGBT with high switching the current ripple is reduced. Consequently, developed drive systems have high performance and accurary on speed control. There are proved in experimental results.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.781-782
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• 2006

This paper presents a drive strategy to reduce torque ripple of a permanent magnet Brushless DC Motor(BLDCM) with short $120^{\circ}$ flat top Back Electromotive Force(Back-EMF). In this strategy, the phase Back-EMF is divided into four sections. Then, in each section the phase current is regulated by corresponding PWM duty ratio to compensatethe torque ripple caused by imperfect Back-EMF. A program based on this strategy has been implemented in MATLAB@Simulink. The validity of the presented method is verified by simulation results.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제54권6호
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• pp.269-277
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• 2005

In this paper, designs of an Interior Permanent Magnet Synchronous Motor (IPMSM) and its motor driver for 42V automotive air condition system are introduced. The characteristics of the IPMSM are predicted by using d-q equivalent circuit having the parameters, such as current phase angle, d-q axis inductances, core loss resistance, etc. The experimental and analysis results of the prototype are compared to show validity of the analysis method, and to give analyzed characteristics in detail. As the result, an improved IPMSM is designed to widen the operating speed limit of prototype; a cost effective AC drive are considered at the same time.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.985-990
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• 2003

With the rotational speed of the hard disk drive (HDD) increased, the low frequency structural vibration induced by the unbalance force gives rise to the structure home noise of the personal computer, and finally degrades the noise quality. As the unbalance of the hard disk drive is decided by the mechanical assembly allowance between clamping and platter disk, there is limit to control this unbalance by the improved assembly method. To improve the noise and vibration performance of PC, basically the unbalance of HDD needs to be measured absolutely and reduced during the stage of the disk assembly. This study introduces the HDD unbalance measurement methods of the absolute magnitude based on the mobility concept, and the unbalance location information with the acceleration orbit.

• 한국안전학회지
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• 제14권1호
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• pp.55-65
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• 1999

Fuzzy logic fuzzy set theory is recently getting increasing emphasis in process control applications. This paper describes application of fuzzy logic in a speed control system that uses a phase controlled bridge converter and a separately excited dc motor. The fuzzy control is used to linearize the transfer characteristics of the converter in discontinuous conduction mod occurring at light load and high speed. The fuzzy control is then extended to the current and speed control loops replacing the conventional PI control method. The control algorithms have been developed in detail and verified by simulation of a DC motor(DM) drive system. The simulation result indicates the superiority of fuzzy control over the conventional control methods. Fuzzy logic seems to have a lot of promise in the applications of power electronics.