• 한국산학기술학회논문지
• /
• 제12권8호
• /
• pp.3644-3653
• /
• 2011

본 연구는 수처리 주요공정의 소독공정에 대한 자동운전 구축현황과 목표주입율 결정시 체류시간동안 염소 소모량을 분석하고 활용하기 위한 기술을 연구하고 제시하는데 있다. 본 연구를 위하여 자동운전을 위한 시설물 구조 및 하부설비 설치현황을 조사하였으며, 현 시스템의 문제점을 분석하고 해결을 위한 자동운전 프로그램을 개발하여 적용하였으며 이에 따른 효과도 분석 제시하였다. 특히 시지연공정 및 다변수 공정제어에 적합한 모델예측제어 알고리즘을 적용하여 환경인자와 반응시간 등의 상관관계를 분석하고 최적 제어 입력값을 추론할 수 있도록 함으로써 안정적인 공정제어가 가능함을 모델평가를 통하여 확인하였다.

• Journal of Power Electronics
• /
• 제17권1호
• /
• pp.232-241
• /
• 2017

Advanced control algorithms must be used to make wind power generation truly cost effective and reliable. In this study, we develop a new and simple control scheme that employs model predictive control (MPC), which is used in permanent magnet synchronous generators and grid-connected inverters. The proposed control law is based on two points, namely, MPC-based torque-current control loop is used for the generator-side converter to reach the maximum power point of the wind turbine, and MPC-based direct power control loop is used for the grid-side converter to satisfy the grid code and help improve system stability. Moreover, a simple prediction scheme is developed for the direct-drive wind energy conversion system (WECS) to reduce the computation burden for real-time applications. A small-scale WECS laboratory prototype is built and evaluated to verify the validity of the developed control methods. Acceptable results are obtained from the real-time implementation of the proposed MPC methods for WECS.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
• /
• pp.774-779
• /
• 1998

For the speed control of motors, the position or speed sensors are necessary to obtain the position information of the rotor. Specially, SRM(Switched Reluctance Motor) needs an accurate rotor position data because both the rotor and the stator have a salient pole structure. High functional sensors like resolver or encoder are expensive and have complex connecting lines to the controller so the pure signals are apt to be mixed with noised. In the sight of SRM drives, the high temperature, heavy dust, and the EMI surroundings reduce the reliability of speed and position sensors. Therefore, the speed and position sensorless control algorithms using observer have been accepted widely. In this paper An adaptive sliding observer is described to control the SRM without speed or position sensors. The adaptive sliding observer is set on the basis of variable structure control theory. The sliding surface is constructed by current error terms and this surface guarantees the errors converge to "zero". The stability of observer is affirmed by Lyapunov stability analysis and popov's hyper stability theory.ty theory.

• 대한전자공학회논문지SD
• /
• 제44권8호
• /
• pp.16-21
• /
• 2007

본 논문은 구조물 모니터링을 위한 광섬유 센서 시스템의 수신단 응용을 위한 CMOS 기반의 가변 이득 증폭기 집적회로 설계에 초점을 두고 있다. 차동증폭기와 선형 linear-in-dB 제어기를 사용한 3단 가변 이득 증폭기를 제시하였다. 제안된 가변이득 증폭기는 전류의 비에 의해 증폭기의 이득이 linear-in-dB 하게 조절되는 일반적인 가변 이득 증폭기의 변형된 형태이다. 본 논문에서 제안된 가변 이득 증폭기는 1.5 dB의 간격으로 77 dB의 다이내믹 영역을 가졌다. 이득오차는 77 dB 다이내믹 영역에서 1.5 dB 이하를 얻었다. 동작범위는 10 MHz를 얻었으며, 단일 1.8 V 전압에서 13.8 mW의 전력소모 특성을 보였다. 이 가변 이득 증폭기는 Magnachip 사의 $0.18{\mu}m$ CMOS 공정을 사용하여 구현되었으며, 유효면적은 $430{\mu}m{\times}350{\mu}m$ 이었다. 제안된 가변 이득 증폭기는 구조물 모니터링을 위한 광섬유 센서 시스템의 수신단에 적용이 가능하였다 측정 결과에 따라 제안된 방법은 다이내믹 영역의 증대와 좋은 linear-in-dB 특성 관점에서 유효하였다.

• Journal of Power Electronics
• /
• 제15권5호
• /
• pp.1305-1317
• /
• 2015

Distributed generation systems (DGSs) have been getting more and more attention in terms of renewable energy use and new generation technologies in the past decades. The self-excited induction generator (SEIG) occupies an important role in the area of energy conversion due to its low cost, robustness and simple control. Unlike synchronous generators, the SEIG has to absorb capacitive reactive power from the outer device aiming to stabilize the terminal voltage at load changes. This paper presents a novel static VAR compensator (SVC) called a magnetic energy recovery switch (MERS) to serve as a voltage controller in SEIG powered DGSs. In addition, many small scale SEIGs, instead of a single large one, are applied and devoted to promote the generation efficiency. To begin with, an expandable mathematic model based on a d-q equivalent circuit is created for parallel SEIGs. The control method of the MERS is further improved with the objective of broadening its operating range and restraining current harmonics by parameter optimization. A hybrid control strategy is developed by taking both of the stand-alone and grid-connected modes into consideration. Then simulation and experiments are carried out in the case of single and double SEIG(s) generation. Finally, the measurement results verify that the proposed DGS with SVC-MERS achieves a better stability and higher feasibility. The major advantages of the mentioned variable reactive power supplier, when compared to the STATCOM, include the adoption of a small DC capacitor, line frequency switching, simple control and less loss.

• Journal of Power Electronics
• /
• 제3권2호
• /
• pp.99-114
• /
• 2003

This paper presents a feasible development on a highly accurate quick response adjustable speed drive implementation fur general purpose induction motor which operates on the basis of sensorless slip frequency type vector controlled sine-wave PWM inverter with an automatic tuning machine parameter estimation schemes. In the first place, the sensorless vector control theory on the three-phase voltage source-fed inverter induction motor drive system is developed in slip frequency based vector control principle. In particular, the essential procedure and considerations to measure and estimate the exact stator and rotor circuit parameters of general purpose induction motor are discussed under its operating conditions. The speed regulation characteristics of induction motor operated by the three-phase voltage-fed type current controlled PWM inverter using IGBT's is illustrated and evaluated fur machine parameter variations under the actual conditions of low frequency and high frequency operations for the load torque. In the second place, the variable speed induction motor drive system, employing sensorless vector control scheme which is based on three -phase high frequency carrier PWM inverter with automatic toning estimation schemes of the temperature -dependent and -independent machine circuit parameters, is practically implemented using DSP-based controller. Finally, the dynamic speed response performances for largely changed load torque disturbances as well as steady state speed vs. torque characteristics of this induction motor control implementation are illustrated and discussed from an experimental point of view.

• 전기전자학회논문지
• /
• 제23권3호
• /
• pp.1061-1067
• /
• 2019

본 논문에서는 PTWS 방식을 이용한 고집적화된 AMOLED용 3-채널 DC-DC 변환기의 설계한다. 양의 전압 $V_{POS}$는 경부하에서 효율을 제고하기 위해 SPWM 듀얼모드와 PTWS 방식을 적용한 부스트 변환기로 설계한다. 음의 전압 $V_{NEG}$는 전력 손실을 줄이기 위해 PSM 방식을 적용한 0.5x 인버팅 차지펌프를 이용해 설계하고, 추가적인 전압 $V_{AVDD}$는 LDO를 이용하여 설계한다. 제안된 DC-DC 변환기는 $0.18{\mu}m$ BCDMOS 공정을 사용하여 시뮬레이션을 한 결과 부하전류 1mA~70mA에서 전력효율 56.9%~90.2%를 가지고, 양의 전압 $V_{POS}$에서 최대 5mV의 출력 리플을 가졌다.