• 전력전자학회논문지
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• 제24권3호
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• pp.207-214
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• 2019

In this study, discrete-time domain analysis is proposed to investigate the input current of a buck AC/DC light-emitting diode (LED) driver. The buck power factor correction converter can operate in both discontinuous conduction mode (DCM) and continuous conduction mode (CCM). Two discontinuous and two continuous conduction operating modes are possible depending on which event terminates the conduction of the main switch in a switching cycle. All four operating modes are considered in the discrete-time domain analysis. The peak current-mode control with slope compensation is used to design a low-cost AC/DC LED driver. A slope compensation design of the buck AC/DC LED driver is described on the basis of a discrete-time domain analysis. Experimental results are presented to confirm the usefulness of the proposed analysis.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.1989-2000
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• 2015

In this paper, digital peak current mode control for single phase H-bridge inverters is developed and implemented. The digital peak current mode control is achieved by directly controlling the PWM signals by cycle-by-cycle current limitation. Unlike the DC-DC converter where the output voltage always remains in the positive region, the output of DC-AC inverter flips from positive to negative region continuously. Therefore, when the inverter operates in negative region, the control should be changed to valley current mode control. Thus, a novel control logic circuit is required for the function and need to be analyzed for the hardware to track the sinusoidal reference in both regions. The problem of sub-harmonic instability which is inherent with peak current mode control is also addressed, and then proposes the digital slope compensation in constant-sloped external ramp to suppress the oscillation. For unipolar PWM switching method, an adaptive slope compensation in digital manner is also proposed. In this paper, the operating principles and design guidelines of the proposed scheme are presented, along with the performance analysis and numerical simulation. Also, a 200W inverter hardware prototype has been implemented for experimental verification of the proposed controller scheme.

• 센서학회지
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• 제8권3호
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• pp.259-264
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• 1999

The $CO_2$ measuring system using infrared sensor has the variance according to the temperature change. Therefore, the temperature compensation should be needed to obtain a reliable measurement. In this study, the sensor module consist of infrared $CO_2$ Sensor, IR Source, pipe and the heater and measuring system has amplifier, A/D converter and microprocessor. And we suggest a method to reduce the error by using the PID temperature control. We use optimum parameters setting of Ziegler & Nichols as well as PID temperature control algorithm for the temperature compensation. In this method, PID optimum parameter is set from dummy time(L) and maximum slope(R). As a result of using this PID temperature control, it is founded that it has the fast response and low steady state error. Therefore, it is certainly proved that this is very suitable algorithm to correct the error on measurement.

• 대한기계학회논문집A
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• 제32권10호
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• pp.823-830
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• 2008

We present a high-accuracy digital-to-analog (DA) actuator using a load spring, specially designed to compensate the output displacement errors caused by fabrication errors. The compensated linear DA actuator is capable to change the slope of input-output modulation line in order to compensate fabrication errors. We design, fabricate, and characterize three different prototypes: one uncompensated design and two compensated designs respectively for a specific value and for a given range of fabrication error. The compensated linear DA actuators show the output displacement errors of $-0.20{\pm}0.23{\mu}m\;and\;-0.13{\pm}0.18{\mu}m$, respectively, reduced by 64.3% and 76.8% of the output displacement error, $0.56{\pm}0.20{\mu}m$, produced by the conventional uncompensated linear DA actuator. We experimentally verify the fabrication error compensation capability of the present compensated linear DA actuators, thus demonstrating high-accuracy actuation performance immune to fabrication errors.

• 한국전자파학회논문지
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• 제28권11호
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• pp.920-923
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• 2017

본 논문에서는 고속 주행환경 채널 측정에 적합한 SIMO 채널 사운더의 내부 파라미터를 설계하고, 5.89GHz C-ITS가 시범 설치된 여주 스마트 하이웨이에서 제안된 측정 방식을 적용하여 광대역 채널 특성을 측정하고 결과를 분석한다. 실 환경에 적합한 수신 배열 구조 설계를 바탕으로 도플러 위상 변화에 대한 선형 기울기 보상방식을 적용하여, 멀티패스 환경에서 도래각 정보 및 주변 환경에 의한 도플러 영향에 대하여 신뢰할 수 있는 결과를 제시하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 심포지엄 논문집 정보 및 제어부문
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• pp.381-382
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• 2007

Recently fishing industry is interested in efficient and automated fishing implementations to reach the level of the international leading technology. One of the important device used in fishing boat is an automated electric compass that harnesses the GPS and terrestrial magnetic sensor. The electric compass is desired to be minimized in size while keeping a high effectiveness in the characteristic of a magnetic compass. This device also can be used as a heading angle sensor to construct auto-navigation system in a small size of ships. However, there exists measurement errors induced from the slope of terrestrial magnetic sensor caused by the motion of boat. In this paper, a method has been proposed removing the measurement error arising from the slope of terrestrial magnetic sensor when the ship is in motion. We have designed a sensor with two DOF(degree of freedom) and a weight to maintain the horizontality of the sensor. Through this research, the hardware has been designed and also a test has been performed. The test shows a promissory result.

• 한국산학기술학회논문지
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• 제13권12호
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• pp.6034-6039
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• 2012

본 논문에서는 모바일 로봇이 이동함에 있어 경사면을 만났을 경우 이를 극복하여 주행하는 경우가 발생할 수 있는데 이때 모바일 로봇 시스템 자체가 가지고 있는 슬립 문제가 주행을 진행함에 있어서 더욱 심하게 나타날 수 있기에 이를 해결하고 목표점까지의 안전한 직진 주행을 하기위한 모델 적응 퍼지 제어 방법을 기반으로 하는 모바일 로봇의 주행 제어 알고리즘을 제안하고자 한다. 제안하고자 하는 모델 기반 적응 퍼지 제어기의 경우 먼저, 모바일 로봇의 등반 조건을 확인한 후 경사면을 모바일 로봇이 극복 주행을 할 수 있는지를 판단하고 만약 가능하다면 모바일 로봇의 동역학 모델을 포함한 모델 기반 제어기를 설계하여 극복 주행 제어를 하고자 한다. 이러한 경우 모바일 로봇 시스템의 안정성 보장 및 지면 마찰력 그리고 외란 보상 등이 충분히 고려된 제어기 설계가 가능할 것이다. 또한, 설계하고자 하는 제어 기법 중 적응 퍼지 제어 방법의 경우 모바일 로봇의 동특성을 충분히 반영한 모델인 비선형 Non-holonomic 시스템과 모바일 로봇의 슬립 문제 해결 등에 충분히 유용할 것이고 이를 컴퓨터 시뮬레이션을 통해 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 F
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• pp.2682-2684
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• 1999

This paper presents design and stability analysis of the constant frequency Flyback type converter using average current-mode control. The average current-mode control has been recently reported, and superior characteristics over a peak current-mode control such as a good tracking performance of an average current, no slope compensation and noise immunity. By the improvement of PM(Phase Margin) obt from applying the compensator in the current loop, the stability of designed flyback convert more improved. The validity of designed convert confirmed by simulation and experimental result

• 한국항행학회논문지
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• 제15권4호
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• pp.495-501
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• 2011

GPS 수신기의 신호 추적 루프에서 추적 오차를 추정하는 판별기(Discriminator)의 특성은 잡음 전력에 의해 영향을 받으며, 실제로 판별기 함수의 기울기는 잡음 전력이 커질수록 작아지는 특성을 보인다. 본 논문에서는 추정한 C/N0를 이용하여 작아진 기울기를 보상할 수 있는 방법을 연구하였으며, GPS 수신기의 신호 추적 루프중에서 측위 성능에 직접적인 영향을 주는 코드 추적 루프에 적용함으로써 일반적인 판별기보다 더 정확한 추적 오차를 가지는 코드 추적 루프 설계 기법을 제안한다. 또한 모의실험 결과로부터 20g/s의 기동을 갖는 항체에 대하여 제안한 코드 추적 루프의 정확도가 약 50% 개선되는 것을 확인하였다.

• 자동차안전학회지
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• 제13권4호
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• pp.39-52
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• 2021

This paper presents a longitudinal acceleration controller that can be applied to real vehicles (nonlinear and time-varing systems) with only a simple experiment regardless of the type of vehicle and the control interface structure. The controller consists of a feedforward term for fast response, a zero-throttle acceleration compensation term, and a feedback term (P gain) to compensate for errors in the feedforward term, and another feedback term (I gain) to respond to disturbances such as slope. In order to easily apply it to real vehicles, there are only two tuning parameters, feedforward terms of throttle and brake control. And the remaining parameters can be calculated immediately when the two parameters are decided. The tuning procedure is also unified so that it can be quickly and easily applied to various vehicles. The performance of the controller was evaluated using MATLAB/Simulink and Truksim's European Ben model. In addition, the controller was successfully implemented to 3 medium-sized vehicle (HMC Solati), which is composed of different control interface characteristic. Vehicle driving performance was evaluated on the test track and on the urban roads in Siheung and Seoul.