• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2021.05a
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• pp.584-588
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• 2021

The impedance of the speaker is likely to be recognized as a fixed value. However, speaker impedance continues to vary with frequency variation, especially larger in resonant frequency region. The sound pressure level of loudspeakers is determined by the current flowing throughout the coil that consists loudspeakers. If loudspeakers are driven by voltage, sound pressure level of the loudspeaker is distorted by the variation of loudspeaker impedance. Current-drive of loudspeakers can solve this problem, but distortion of sound pressure level occurs in low frequencies due to resonance. The distortion can degrade the sound quality of the sound system. So to solve this problem, In this paper, we propose a resonance compensation circuit using DSP. we simulates audio systems using an equivalent model of loudspeakers to verify distortion of sound pressure level due to impedance variation and propose a circuit to compensate it. The proposed circuit is configured using a state variable filter and it can adjust the center frequency and output, so it will be used various sound systems.

• Proceedings of the KIPE Conference
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• 2010.11a
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• pp.15-16
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• 2010

본 논문에서는 최소의 진동/소음을 가지는 SRM을 설계하기 위하여 고정자와 회전자의 Skew에 따른 단상 6/6 SRM의 소음/진동 특성을 비교, 분석하였다. SRM(Switched Reluctance Motor)에 발생하는 소음/진동의 주 원인은 모터 구동 시 Yoke 에 발생하는 방사방향 힘의 변화라고 할 수 있다. Yoke에 작용하는 힘은 돌극이 위치한 곳에 집중되므로 더욱 큰 진동을 유발하지만 회전자와 고정자에 동일한 Skew를 적용시키면 힘을 받는 Yoke의 면적은 늘어나게 되고, 따라서 방사방향의 힘을 요크 전체로 분산 시킬 수 있다. 이에 따라 스위치 온, 오프시 요크에 인가되는 방사방향의 힘의 최대치는 감소하게 되어 진동/소음이 현저히 줄어들게 된다. 본 논문에서는 최소의 진동/소음을 가지는 SRM을 설계하기 위하여 시뮬레이션을 통하여 회전자와 고정자의 스큐 각도에 따른 힘의 분포를 분석하였다. 시뮬레이션 결과를 바탕으로 하여 대표적인 특성을 가진 $0^{\circ}$, $18^{\circ}$의 SRM을 설계하여 소음/진동을 측정한 결과 제안한 방식이 소음/진동을 현저하게 감소시키는 효과를 가짐을 입증하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.10
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• pp.319-330
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• 2016

Recently, 3D printing technology has been applied to make a concept model and working mockup of an industrial application. On the other hand, this technology has limited applications in industrial products due to the materials and reliability of the 3D printed product. In this study, the components of a full cord switch module are proposed as a case of a 3D printed component that can be used as a substitute for a short period. These are hub-driven and lever lockup components that have the structural characteristics of breaking down frequently in the emergency operating status. To ensure the structural strength for a substitute period, research of structure optimization was performed because 3D printing technology has a limitation in the materials used. After optimizing the structure variables of the hub-driven component, reasonable results can be drawn in that the safety factors of the left and right switching mode are 1.243 (${\Delta}153.67%$) and 3.156 (${\Delta}404.96%$). The lever lockup component has a structural weak point that can break down easily on the lockup-part because of a cantilever shape and bending moment. The rib structure was applied to decrease the deflection. In addition, optimization of the structural variables was performed, showing a safety factor of 7.52(${\Delta}26%$).

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.289-290
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• 2016

기존 자가발전 운동기구의 경우, 입력 임피던스가 고정되어 있어 운동 강도조절이 불가능한 단점이 있다. 또한 운동에너지 회수용 계통연계형 인버터는 특정한 입력전압의 범위를 유지하기위해 큰 용량의 커패시터 사용이 불가피하여 기구의 부피 및 원가 상승문제를 발생시킨다. 본 논문은 능동부하 스위치 구동회로를 사용한 자가발전 운동기구용 부스트 컨버터를 제안한다. 제안 방식은 입력 전류 제어를 통해 운동 강도 조절이 가능하고, 계통연계형 인버터의 전압 범위를 유지하기 위한 큰 용량의 커패시터를 삭제하고 능동부하 스위치 구동회로를 연결함으로써 기구의 소형화 및 원가 저감이 가능하도록 한다. 본 논문에서는 제안된 회로의 이론적 특성을 분석하고 모의실험을 통해 확인하였으며, 150W급 자가발전 운동기용 부스트 컨버터에 적용하여 실험을 통해 가능성을 검증하였다.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.6
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• pp.57-64
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• 1995

This paper deals with the modeling and simulation to control the torque and speed of an induction motor using field-oriented control methods. Rotor flux is estimated using the indirect sensing method based on the rotor circuit equation in the synchronously rotation reference frame, and slip angle and rotor position are calculated from rotor angular velocity and stator current. As results of modeling and digital simulation with a voltage source inverter, it is shown that the proposed scheme gives good static and dynamic performance to the induction motor drive.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.10 no.6
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• pp.88-95
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• 1996

The ultrasonic motor(USM) has good characteristics such as compact size, silent motion, high speed responce, low speed and high torque. The USM is driven by 2-phase AC electricity. The control parameters of USM are voltage, phase, and frequency of input powers, etc. In this paper, a voltage difference control is proposed. The voltage difference control has more advantage than phase difference control. Specially, current and power is lower than that of phase difference control. For this voltage diffrence control, we designed USM controller to adjust volatage and phase using PLSI(Programmable Large Scale Integration).

• Proceedings of the KIPE Conference
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• 1999.07a
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• pp.581-584
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• 1999

본 논문에서는 12펄스 위상제어 정류기 및 수동 필터와 능동필터로 구성된 KCCH 싸이클로트론 전자석용 고정밀, 고안정 전류 전원장치를 위한 각 구성 부분의 제어 및 설계 특징은 다음과 같다. 12펄스 싸이리스터 컨버터의 출력전압 제어를 위하여 아날로그 phase-locked oscillator 점호방식과 함께 부하에 비해 빠른 동특성을 가지는 내부 전압제어 루프를 구성하여, 입력전원과 변압기의 불평형에 의해 발생하는 저차고조파를 줄어들게 하였다. LC 수동필터와 MOSFET으로 구성된 능동필터를 직렬로 연결하여 출력전압 리플을 허용치 이하로 낮추었다. 12펄스 컨버터 출력전압 리플의 최대 peak-to-peak값이 0.1% 이하가 되도록 수동필터 값을 설계하였으며 설계과정을 제시하였다. 16bit D/A와 A/D에 의해 디지털로 제어되는 pass bank MOSFET 레귤레이터는 출력리플의 slow drift 제어와 설정치 값의 정확한 제어를 가능하게 한다. 또한 MOSFET는 전압 구동형 소자이며 turn-on 전류 도통 시에 양의 저항계수를 갖기 때문에, 첫째 전류 구동소자에 비해 간단한 구동회로를 가지며, 둘째 소자의 병렬 연결이 용이하다는 이점을 갖는다. 본 논문에서는 전류 전원장치 각 부분의 설계에 대하여 상세한 설계결과를 제시하며, 실험결과를 통하여 제안된 설계방식의 우수한 정적 및 동적 특성을 입증한다.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.5
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• pp.70-76
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• 2010

It is required to analyze the characteristics of inverter-fed induction motor according to the increase of inverter uses. However the previous simulation researches usually uses simplified induction motor model and fixed power source because the difficulties of their modeling and analysis. In this study, high frequency induction motor is simulated and the induction motor model considering high frequency characteristics is developed and it is combined with inverter model. With these, from the sinusoidal commercial frequency to PWM high frequency, induction motor characteristics can be simulated and analyzed.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.48 no.3
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• pp.6-12
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• 2011

Electric vehicles and robots are real-time distributed control systems composed of multiple drive subsystems using micro controller units. Each control subsystem should be modular, compact, power saving, interoperable and fault tolerable in order to be incorporated into the networked real-time distributed control system. Under the networked real-time distributed control the synchronization problem can be occurred to the position and orientation tracking control due to the load variance, mismatch and time delay between the multiple drive subsystems. This paper suggests two types of position synchronization control of the single link manipulators. One of them is composed of cross controller, Kalman filter and disturbance observer, and the other uses the generation of target trajectories to minimize the gradient vector of the scalar function which is composed of the sum of square errors between the reference input vector and the output vectors. The availability of the proposed control schemes is shown through the control experiments.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.13 no.12
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• pp.965-971
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• 2003

To reach high areal density, less track pitch is expected and more servo bandwidth is required. One approach to overcoming the problem is by using dual stage servo system. For this system. we have suggested new milliactuator based on the shear mode of piezoelectric elements to drive the head suspension assembly. In this paper, we introduce milliactuator and controller design method, PQ method. PQ method reduces the controller design problem for DISO (dual-input/single-output) systems to two standard controller design problems for SISO ( single-input/single-output) problems. The first part of PQ method directly addresses the issue of actuator output contribution, and the second part allows the use of traditional loop shaping to achieve the overall system performance. This paper shows how to employ the PQ method to meet aggressive close-loop performance specifications for a disk drive system with a VCM and piezoelectric milliactuator.