• 전력전자학회:학술대회논문집
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• 전력전자학회 2014년도 추계학술대회 논문집
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• pp.203-204
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• 2014

In this paper, single-phase uninterruptible power supply design method is presented. In this control scheme, input current, output current and output voltage are used. For voltage control PR controller is used and that for current controller is PI controller. The gains for controllers are sought by the classical method for determining gains. Throughout simulations the performance of single-phase UPS is verified.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1992년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 19-21 Oct. 1992
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• pp.194-199
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• 1992

In this paper, each section of an Electrolytic Tinning Line is mathematically modelled with the coupling effect accounted for. Based on the modelling, PI and feedforward controllers are designed for speed control or tension control of each section of the process line. It is shown through simulatios that the tension of the stip is controlled precisely along the entire line and the contituety of the process is insured when using the efficient control of loop towers.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1990년도 한국자동제어학술회의논문집(국내학술편); KOEX, Seoul; 26-27 Oct. 1990
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• pp.85-89
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• 1990

In this paper, the design of boiler drum level control system is important in power plant is studied. First of all, pressure compansation of level for boiler drum which is close tank with high temperature and pressure is designed. Physical penomena of drum level are analysed, controllers are designed, and simulation results are shown. Designed controller have a good performance compare with PI controller. Predictive controller of boiler drum level control system is proposed. It will be good system for boiler drum level control to reject the disturbance according to lead increase or decrease.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.310-313
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• 2005

In this paper, four quadrant CBPS(Compact Bipolar Power Supply) which development and study using universal PWM controller. The CBPS has 24V DC-link voltage, +/-5A output current, 50kHz switching frequency and 30Hz full load bandwidth using FET device. Proposed system has two independent PWM controllers for each full-bridge switch leg drive and PI control loops for current regulations. It is shown experimental results that good step response of the current output.

• Journal of Electrical Engineering and Technology
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• 제10권5호
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• pp.2170-2178
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• 2015

This paper presents the effective and reliable speed control of PMDC motors under variable loads and reference speeds. As is known DC motors are more preferred in industrial practices. This is that, the PMDC motors don’t require brush and commutator care and to increase in torque per motor depending on developments in power electronics. In this study, proportional-integral controller (PI) and fuzzy logic controller (FL) have been designed for speed control of PMDC motor. In the design of these controllers, characteristics such as minimum overrun time, response time to the load, settling time and ideal rise time have been taken into consideration for better stability performance. In this design, the best system response was searched by examining the effect of different defuzzification methods onto the fuzzy logic system response. In conclusion, it has been seen that FL controller has a better performance for variable speed-load control of PMDC motor compared to PI controller.

• 한국자동차공학회논문집
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• 제23권1호
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• pp.56-64
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• 2015

This study presents a model-based gain scheduling strategy for PI-based EGR controllers. The air-to-fuel ratio is used as an indirect measurement of the EGR rate. In order to cope with the nonlinearity and parameter varying characteristics of the EGR system, we proposed a static gain model of the EGR system using a new scheduling parameter. With the 810 steady-state measurements, the static gain model achieved 0.94 of R-squared value. Based on the static gain of the EGR system, the PI gains were robustly designed using quantitative feedback theory. Consequently, the gains of the PI controller are scheduled according to the static gain parameter of the EGR path in runtime. The proposed model-based gain scheduling strategy was validated through various operating conditions of engine experiments such as setpoint step responses and disturbance rejections.

• Korean Chemical Engineering Research
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• 제58권2호
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• pp.184-189
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• 2020

Van de Vusse 반응기는 정상상태 입출력 관계에서 최대값을 그리고 이 최대값을 기준으로 동특성의 형태가 크게 바뀌는 특성을 보인다. 운전영역에 따라 정상상태 이득의 부호가 바뀌고, non-minimum phase 동특성 등의 제어를 매우 어렵게 하는 특성들이 나타난다. 매우 많은 비선형제어 방법들과 새로이 고안되고 있는 방법들이 이 Van de Vusse 반응기 공정에 적용되어 그 성능 검증이 이루어지고 있다. 이 반응기의 실제 예가 보고되어 있으나, 화학반응 특성상 제어기 실험에 일상적으로 사용되기에는 어려움이 많아 대부분 모사연구에 그치고 있다. 여기서는 이 Van de Vusse 반응기의 특성을 모두 구현하는 액위시스템을 제작하고, 새로이 고안되는 비선형 제어기의 성능을 밝히는 기준이 될 수 있는 간단한 두 제어 방법의 실험 결과를 제안하고자 한다. 액위시스템 실험장치와 제안된 제어 방법들은 매우 간단하며, 비선형 제어기의 성능과 현장 적용 가능성을 검증하는데 유용하게 사용될 수 있을 것이다.

• 한국지능시스템학회논문지
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• 제13권3호
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• pp.322-327
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• 2003

가압경수로 원자력 발전소의 증기발생기 수위는 유량의 변동에 상반되는 수축(shrink)과 팽창(swell) 효과 등의 특성을 가지고 있으므로 제어가 어려운 대상으로 알려져 있다. 본 논문에서는 신경망을 이용하여 원자력발전소에서 사용되고 있는 두 개의 PI 제어기 중 부적절한 게인으로 조정된 제어기를 먼저 선택하고, 선택된 제어기의 게인을 퍼지 논리를 적용하여 조정하도록 구성하였다. 게인 조정을 위해 사용되는 기본 정보는 수위, 급수량, 그리고 증기량이다. 이 세 가지의 정보를 바탕으로 신경망을 통해 수위 제어기 또는 급수량 제어기 둘 중 하나의 제어기가 선택한 후 퍼지 자기동조기(self-tuner)를 이용하여 PI 제어기의 게인을 알맞게 조정하게 된다. 퍼지 자기동조기의 규칙은 증기발생기의 상태를 표현하는 입ㆍ출력 데이터의 특성으로부터 추출하였다. 이상의 두 과정을 통해 적절한 제어기를 선택하고, 선택된 제어기의 게인을 알맞게 조정하는 것이 본 논문의 목적이다.

• Journal of Electrical Engineering and Technology
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• 제3권3호
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• pp.391-400
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• 2008

Multi-pulse topology of converters using elementary six-pulse GTO - VSC (gate turn off based voltage source converter) operated under fundamental frequency switching (FFS) control is widely adopted in high power rating static synchronous compensators (STATCOM). Practically, a 48-pulse ($6{\times}8$ pulse) configuration is used with the phase angle control algorithm employing proportional and integral (PI) control methodology. These kinds of controllers, for example the ${\pm}80MVAR$ compensator at Inuyama switching station, KEPCO, Japan, employs two stages of magnetics viz. intermediate transformers (as many as VSCs) and a main coupling transformer to minimize harmonics distortion in the line and to achieve a desired operational efficiency. The magnetic circuit needs altogether nine transformers of which eight are phase shifting transformers (PST) used in the intermediate stage, each rating equal to or more than one eighth of the compensator rating, and the other one is the main coupling transformer having a power rating equal to that of the compensator. In this paper, a two-level 48-pulse ${\pm}100MVAR$ STATCOM is proposed where eight, six-pulse GTO-VSC are employed and magnetics is simplified to single-stage using four transformers of which three are PSTs and the other is a normal transformer. Thus, it reduces the magnetics to half of the value needed in the commercially available compensator. By adopting the simple PI-controllers, the model is simulated in a MATLAB environment by SimPowerSystems toolbox for voltage regulation in the transmission system. The simulation results show that the THD levels in line voltage and current are well below the limiting values specified in the IEEE Std 519-1992 for harmonic control in electrical power systems. The controller performance is observed reasonably well during capacitive and inductive modes of operation.

• 항공우주시스템공학회지
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• 제11권1호
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• pp.14-21
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• 2017

매우 큰 정안정성($C_{L{\alpha}}$)을 갖는 틸트덕트 운동모델에 대해 선형 파라미터를 갖는 Sigma-Pi 신경망(SPNN) 제어법칙을 적용하였다. 기존의 비례적분미분(PID) 제어기는 매우 큰 정안정성을 갖는 운동모델이 갖는 강한 기수숙임 문제를 해결하기 어려웠고 이로인해 제어성능을 높일 수 없었다. 이와 달리 외부루프와 내부루프에 모두 적용된 SPNN 제어기는 동역학역변환 및 모델오차를 줄일 수 있는 의사적응제어 명령을 이용해서 과도한 안정성을 개선할 수 있었다. 이를 검증하기 위해서 경로점 추종 시뮬레이션을 이용해서 PID제어 성능과 SPNN제어 성능을 비교하였다.