• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.11-11
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• 2000

A time domain step response in which no overshoot occurs is demanded in many control application. Recently, Kim et al.[4,51 suggested some prototypes of target transfer functions of type I which can satisfy such a purpose. However, if a plant contains zeros more than one, then any output feedback control systems should have the same zeros in the closed-loop transfer function. In this paper, we propose two methods that choose the target transfer functions higher than Type I. These methods allow us to reduce the effect of zeros. It is shown through some examples that the proposed scheme can be effectively applied to the controller design problems with no overshoot.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.47 no.5
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• pp.71-79
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• 2010

This paper presents a design of a LLC resonant controller IC. LLC resonant controller IC controls the voltage of the 2nd side by adjusting frequency the input frequency of the external resonant circuit. The clock generator is integrated to provide the pulse to the resonant circuit and its frequency is controlled by the external resistor. Also, the frequency of the VCO is adjusted by the feedback voltage. The protection circuits such as UVLO(Under Voltage Lock Out), brown out, fault detector are implemented for the reliable and stable operation. The HVG, and LVG drivers can provide the high current and voltage to the IGBT. The designed LLC resonant controller IC is fabricated with the 0.35 um 2P3M BCD process. The overall die size is $1400um{\times}1450um$, and supply voltage is 5V, 15V.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.5
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• pp.117-125
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• 1995

An improved robust control law is proposed for uncertain rigid robots. The uncertainty is nonlinear and (possibly fast) time-varying. Therefore, the uncertain factors such as imperfect modeling, friction, payload change, and external disturbances are all addressed. Based on the possible bound of the uncertainty, the controller is constructed. For uncertain flexible-joint robots, some feedback control terms are then added to the proposed robust control law in order to stabilize the elastic vibrations at the joints. To show that the proposed control laws are indeed applicable, the stability study based on Lyapunov function, a singular perturbation approach, and simulation results are presented.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.12
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• pp.1273-1277
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• 2011

This paper proposes a control-based approach for duty cycle adaptation in wireless sensor networks. The proposed method, QCon, controls duty cycle through queue management in order to achieve high performance under variable traffic rates. To minimize energy consumption while meeting delay requirement, we design a feedback controller, which adapts the sleeping time according to dynamically changing traffic by constraining the queue length at a predetermined value. Based on control theory, we analyze the adaptive behavior of QCon and derive conditions for system stability. Results from asymptotic analysis and simulations indicate that QCon outperforms existing scheduling protocol by achieving more energy savings while satisfying delay requirement.

• Proceedings of the KIEE Conference
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• 2003.07d
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• pp.2134-2136
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• 2003

ATM 네트워크 중에서 ABR 서비스만이 피드백(feedback) 메커니즘이 가능하며, 이를 이용한 체증제어(congestion control)연구가 다양한 방법으로 진행되고 있다. 본 연구에서는 현대 제어기법을 이용한 ABR 서비스의 체증제어 문제에 관심을 가지고, ABR 서비스 트래픽의 체증을 억제하고 체증 발생시 제어함으로써 최대의 QoS(Quality of Service)를 보장하도록 한다. 문제해결을 위해 제어 이론을 기반으로 한 ABR Explicit Rate 알고리즘을 이용하며, 불확실한 외란에 대해서도 강인하고 안정된 성능을 보이는 시스템 모델을 연구한다. 그리고 이 시스템에 대한 $H_{\infty}$ 제어기를 설계하고 시뮬레이션을 통하여 설계한 제어기의 타당성을 보인다.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.9-12
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• 2005

In this paper. we offer a new monitoring system that controls all of the windfar. it can also apply use general wind turbine systems and real meteorological tower. We propose a hierarchical releiable monitoring system connected by wireless communication channels between monitoring host computer and modular slave measuring subsystems. Our system has two hierarchical subsystems: slave measuring systems, and supervisory host computer. We design and implement that the slave measuring subsystems is placed in meteorological tower and wind turbines, and the supervisory host computer in safety zone, The micro-controller in slave measuring system is duplicated using cold-standby method for reliability. The host computer and slave system constructs a feedback system, with wireless communication channel between them. For monitoring and command function, the supervisory computer is implemented with a Personal Computer using graphic user interface. Consequently. we can get a reliable but economic system.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.4
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• pp.677-684
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• 2024

In this paper, the design method of a step-up DC-DC converter based on PWM control was studied for solar power system application. The operating principle of the switching mode step-up type DC-DC converter was analyzed and the basic design method was studied. For photovoltaic system application, an output voltage feedback control algorithm based on PWM control was developed to enable the converter's output voltage to follow the target voltage under variable input conditions. As a procedure to verify the effectiveness of the proposed algorithm, a prototype of a step-up DC-DC converter with a single feedback output voltage was designed and made by boosting the input voltage DC 10V to DC 30V. In experiments with prototypes, it was confirmed that the output voltage of the oscilloscope and LCD accurately followed the target output voltage. In the performance evaluation test, it was confirmed that the output voltage of the oscilloscope and LCD accurately followed the target output voltage by showing an error rate within 1 [%] of the reference voltage.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.439-440
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• 2017

본 논문에서는 지능형 반도체 변압기를 구성하는 Dual Active Bridge (DAB) 컨버터와 계통 연계형 인버터와의 연결에 따른 임피던스 영향을 분석하기 위해 컨버터의 입력 임피던스와 인버터의 출력 임피던스 각각에 대한 전달함수를 분석하고자 한다. 이를 통해 인버터와 컨버터 간의 임피던스 영향을 이론 분석과 모의 시험을 통해 확인하고, 제어기의 설계 방향을 제안하고자 한다.

• Proceedings of the KIPE Conference
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• 2017.07a
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• pp.272-273
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• 2017

계통연계 인버터 시스템은 기존 L 필터보다 낮은 THD를 가지며 저가격의 작은 부피로도 효율적으로 고조파를 저감할 수 있는 LCL 필터를 많이 사용하고 있다. LCL 필터를 가지는 계통연계 인버터의 제어를 위해서는 PI 제어기가 사용되고 있으며 일반적으로 다수의 PI 제어기가 사용되고 있어 많은 제어기 이득을 동시에 설계해야 하는 한계를 지닌다. 본 논문에서는 LCL 필터를 갖는 3상 계통연계 인버터의 상태공간 모델을 이용하여 상태공간에서의 상태 궤환 제어기의 설계기법을 제시한다. 상태 궤환 제어기를 적용함으로서 다수의 PI 제어기 이득을 설계하는 번거로움을 줄일 수 있으며 체계적인 과정으로 제어기가 설계될 수 있다. 제안된 기법의 타당성과 성능이 PSIM 시뮬레이션을 통하여 입증된다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.292-293
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• 2007

본 논문은 연속 시간과 이산 시간 비선형 상호 결합 시스템에 대한 분산 정적 출력 궤한 제어기의 설계에 대해 연구한다. 먼저 퍼지 모델 기법을 이용하여 비선형 상호 결합 시스템을 Takagi-Sugeno (T-S)퍼지 모델로 모델링한다. 각각의 하위 시스템에 대한 정적 출력 궤한 제어기를 병렬 분산 보상(PDC)기법을 이용하여 구한다. 선형 행렬 부등식(LMI)을 통하여 하위 시스템의 안정화를 위한 이득값을 구한다. 이득값을 통하여 하위 시스템들이 안정화되고 그를 통해 전체 상호 결합 시스템이 안정화됨을 모의실험을 통하여 증명한다.