• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.24 no.8
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• pp.70-77
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• 2010

This paper presents the current and speed controller design procedure and their performance for the IPMSM based next generation high speed railway traction system. The next generation high speed railway system is a power distributed type and uses vector control method for a motor speed control. Since the speed and current controller gains of the vector control system directly affects to the transient characteristics and speed control capability, the systematic design of the controllers are required. In this paper the controllers are designed using the IPMSM based next generation high speed railway system parameters. Simulation programs based on Matlab/Simulink is developed. Finally the controller characteristics are analyzed by the simulation results.

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1995.06a
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• pp.741-746
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• 1995

• Journal of the Institute of Electronics and Information Engineers
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• v.51 no.7
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• pp.82-88
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• 2014

An available capacitance increasing phase-locked loop(PLL) with two voltage controlled oscillator gains has been proposed. In this paper, the available capacitance of loop filter is increased by using two positive/negative gains of voltage controlled oscillator (VCO). It results in 1/10 reduction in the size of loop filter capacitor. It has been designed with a 1.8V $0.18{\mu}m$ CMOS process. The simulation results show that the proposed PLL has the same phase noise characteristic and a locking time of conventional PLL.

• Journal of the Korean Institute of Gas
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• v.3 no.1
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• pp.64-74
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• 1999

Using the steady state gains, an appropriate criterion used for the interaction analysis among variables and the loop pairing is suggested. Based upon the suggested criterion derived from the derivative relation of implicit function, the SISO pairing which has minimum interaction among control system variables and good control performance can be determined. The relative effect among diagonal gains and off-diagona gains, which was not considered in other criteria, can be explained deterministically Also, the criterion can be easily applied to partial MIMO pairing. This criterion was applied to several examples to illustrate its usefulness in finding the feasible SISO pairing and MIMO pairing

• Proceedings of the KIEE Conference
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• 2008.04a
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• pp.209-210
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• 2008

본 논문에서는 제어기에 승산형 섭동을 가지는 제어기와 이산시간 특이시스템을 안정화시키는 비약성 제어기 설계방법을 제시한다. 강인 비약성 제어기가 존재할 조건과 제어기 설계방법을 블록최적화가 가능한 선형 행렬부등식 접근방법으로 제안한다. 또한, 제어기의 약성 성도를 표시하는 비약성 척도를 동시에 계산함으로 승산형 섭동의 제어기 최대 변동정도를 제시한다. 제안한 비약성 제어기는 제어기의 이득 변동에도 불구하고 이산 시간 특이시스템의 강인 안정성을 보장한다.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.97-98
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• 2016

본 논문은 위치, 속도, 전류 제어기들이 직렬로 연결된 전동기 구동시스템에서 속도 제어기를 사용하지 않는 위치 제어를 위한 PI-PD 제어기 설계법을 제안한다. 기존의 PI-PD 위치 제어기 설계법과 달리 제안된 제어기의 설계법은 위치 제어기의 대역폭에 따라 이득 값을 설정할 수 있다. 제안된 위치 제어기 설계 성능을 검증하기 위해 IPMSM 구동시스템에서 실험을 통해 유효성을 확인하였다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.489-490
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• 2019

본 연구에서는 태양광 벅 컨버터 제어기에 P&O 알고리즘을 이용하면서 MPPT 알고리즘의 추적 속도를 올리기 위한 최적 태양전지 전압 제어기 설계방법에 대해 제안한다. 제안된 제어기에서는 외부 루프의 MPPT 제어기의 수행 속도를 얼마나 빠르게 하는지에 대한 이론적인 방법을 제시하고 업데이트 주기를 0.1[sec] 이하로 줄이는 것을 목표로 전압제어기는 오버슈트가 업고, 빠른 상승시간을 갖도록 설계하여 MPPT 제어기의 추적 속도를 향상시키는 제어기법을 제안하고, 설계된 제어기 이득을 PSIM 시뮬레이션을 통해 제어기 성능을 검증한다.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.9
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• pp.900-905
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• 2009

A common drain feedback CMOS wideband LNA with current bleeding and input inductive series-peaking techniques is presented in this paper. DC coupling is adopted between cascode and feedback amplifiers, so that the gain and NF of the LNA can be dynamically controlled by adjusting the bleeding current. The fabricated LNA shows the bandwidth of 2.5 GHz. The high gain mode shows 17.5 dB gain with $1.7{\sim}2.8\;dB$ NF and consumes 27 mW power and the low gain mode has 14 dB gain with $2.7{\sim}4.0\;dB$ NF and dissipates 1.8 mW from 1.8 V supply.

• Journal of Navigation and Port Research
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• v.47 no.4
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• pp.256-270
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• 2023

In this study, a sliding mode (SM) controller for dynamic positioning (DP) was specifically designed for a turret connection operation of a ship or an offshore structure in which an arbitrary point on the structure could be controlled as the motion center instead of the center of mass. The SM controller allows control of the arbitrary point and provides capability to manage uncertainties in the dynamics of ships and offshore structures, external forces caused by unknown changing marine environments, and transient performance of DP systems. The Jacobian matrix included in kinematic equations of the controlled object was modified to design the SM controller to control based on an arbitrary point of ships or offshore structures. To ensure robustness of the controller, the Lyapunov stability theory was applied in the design of the SM controller. In general, for robustness in DP control, gain scheduling based on a proportional-derivative (PD) control algorithm is employed. However, finding appropriate gains for gain scheduling complicates the application of DP systems. Therefore, in this study, the SM control algorithm was considered to mitigate the complexity of the DP controller for ships and offshore structures. To validate the proposed SM control algorithm, time-domain simulations were conducted and utilized to evaluate the performance of the control algorithm. The effectiveness of the proposed SM controller was assessed by comparing simulation results with results of a conventional PD control algorithm applied in DP control.

• The Journal of the Korea institute of electronic communication sciences
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• v.2 no.1
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• pp.10-18
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• 2007

In this paper, we extend the multiple time scale control framework to window-based congestion control, in particular, TCP. This is performed by interfacing TCP with a large time scale control module which adjusts the aggressiveness of bandwidth consumption behavior exhibited by TCP as a function of "large time scale" network state. i.e., conformation that exceeds the horizon of the feedback loop as determined by RTT. Performance evaluation of multiple time scale TCP is facilitated by a simulation bench-mark environment which is based on physical modeling of self-similar traffic. If source traffic is not extended exceeding, when RTT is 450ms, in self similar burst environment, performance gain of TCP-SSC is up to 45% for ${\alpha}$=1.05. However, its is acquired only 20% performance gain for ${\alpha}$=1.95 relatively. Therefore we showed that by TCP-MTS at large time scale into a rate-based feedback congestion control, we are able to improve two times performance significantly.