• Proceedings of the KIPE Conference
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• 2013.11a
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• pp.73-74
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• 2013

본 논문은 LED Driver 휘도(Luminance) 제어 방식인 펄스폭 변조(PWM), 진폭변조 방식(PAM)을 조합한 스마트디밍 알고리즘에 대해 제안한다. 제안된 방식은 LED 구동 순방향 전류($I_f$)양에 따라 순방향 전압($V_f$)이 비례적으로 변화되는 특성을 이용한 것으로, LED Backlight 적용 LCM의 소비전력을 저감할 수 있다. 본 논문에서는 스마트 디밍 (CPWAM=Conditional Pulse Width Amplitude Modulation) 알고리즘에 대해 소개하고 실험을 통해 제안된 알고리즘의 타당성을 검증한다.

• Proceedings of the KIEE Conference
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• 2007.04c
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• pp.183-186
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• 2007

This Paper presents a solution to control the Brushless DC Motor(BLDCM) in Hard Disk Drive(HDD) using the Linear Quadratic Regulator(LQR). Generally, The speed of BLDCM in HDD is controlled by the lead angle control or the input voltage control using PAM(Pulse Amplitude Modulation) etc. These control methods have speed overshoot in speed control and need the long time until BLDCM reaches at the steady state. In order to improve the performance, this paper present the PI speed controller using the LQR based on vector control and the rotor position detection methods at the space vector PWM inverter. The proposed methods are proved by the simulation and experimental results.

• Proceedings of the KIEE Conference
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• 1999.07c
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• pp.1039-1041
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• 1999

Recently Advanced Static Var Compensators(ASVC) or STATic Synchronous COMpesator(STATCOM) has been considered as a next generation reactive power controller. [2] STATCOM is a voltage source inverter(VSI) based static VAr compensator with only small capacitors on the do side. The main function of the STATCOM is to keep the bus voltage magnitude at the desired value. [1] This paper compares the PAM STATCOM with PWM STATCOM. The characteristics and the control method of each model is analyzed. And the simulation of STATCOMs based on the above two methods was presented.

• Proceedings of the KIEE Conference
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• 1999.07b
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• pp.630-632
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• 1999

In this paper, we develop intelligent digitally redesigned PAM and PWM fuzzy controllers for nonlinear systems. Takagi-Sugeno fuzzy model is used to model the nonlinear systems and a continuous-time fuzzy-model-based controller is designed based on the extended parallel-distributed-compensation method. The digital controllers are determined from existing analogue controllers. The proposed method provides an accurate and effective method for digital control of continuous·time nonlinear systems and enables us to efficiently implement a digital controller via pre-determined continuous-time TS fuzzy-model-based controller. We have applied the proposed method to the balancing problem of the inverted pendulum to show the effectiveness and feasibility of the method.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.264-269
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• 1998

A proposed soft-switching buck-boost PWM converter has a lot of advantages, Viz., electric isolation, a high power factor, low switching losses, low EMI noise, reduction of the voltage and current stresses, etc. In a new PFC converter, the switching device is replaced by the loss-less snubber circuit to achieve the zero voltage switching (ZVS) at the maximum current. However, the charging current of the capacitor in the loss-less snubber circuit distorts the input current waveforms. To improve the input current waveform, a new duty factor control method is proposed in this paper.

• Proceedings of the KIEE Conference
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• 2000.07b
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• pp.1177-1181
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• 2000

Usually, in many applications. high frequency resonant inverters are used, and the PAM(Pulse Amplitude Modulation), PFM(Pulse Frequency Modulation) or PWM(Pulse Width Modulation) techniques are used to control the output power of resonant inverters. And the resonant inverters have to control the output frequency for the reliable operation under the variable load conditions. In this paper, a new switching scheme is proposed as a resonant frequency following control of resonant inverters. With the proposed method. it can be obtained that optimum resonant frequency and unity output displacement factor under the variable resonant frequency adaptively. The detail algorithm of the proposed switching scheme and its characteristics are discussed. And the veridity of the proposed method is confirmed with the experimental results.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1102-1103
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• 2007

This Paper presents a solution to control the Brushless DC Motor(BLDCM) in Digital Lightening Processor(DLP) using the Linear Quadratic Regulator(LQR). Generally, The speed of BLDCM in DLP is controlled by the lead angle control or the input voltage control using PAM(Pulse Amplitude Modulation) etc. These control methods have speed overshoot in speed control and need the long time until BLDCM reaches at the steady state. In order to improve the performance, this paper present the PI speed controller using the LQR based on vector control and the rotor position detection methods at the space vector PWM inverter. The proposed methods are proved by the experimental results

• Journal of the Korean Society for Precision Engineering
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• v.29 no.7
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• pp.711-716
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• 2012

The purpose of this study was to investigate how the modulation method affects the effectiveness of eliciting tactile sensations by electrical stimulation. Two methods were employed and the results were compared and analyzed; pulse amplitude modulation (PAM) and pulse width modulation (PWM). Thirty-five healthy subjects participated in the experiments to measure the stimulation intensity that began to elicit a tactile sensation - activation threshold (AT). Constant-current monophasic rectangular pulse trains were employed, and the stimulation intensity was varied from zero until the subject felt any uncomfortable sensation. The step size of the stimulation intensity was 100nC/pulse. After each experiment, the subject described the sensation both quantitatively and qualitatively. The two modulation methods did not make a significant difference as far as the AT values were concerned, but most of the subjects showed 'intra-individual' consistency. Also, it was confirmed that our range of the stimulation parameters enabled us to obtain three major tactile sensations; tickling, pressure and vibration. The results suggested that the stimulation parameters and the modulation type should be selected for each individual and that selective electrical stimulation of the mechanoreceptors needs more diversified researches on the electrode design, multi-channel stimulation protocol, waveforms of the pulse train, etc.