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최연옥,서진연,조금배 조선대학교 에너지.자원신기술연구소 1997 에너지·자원신기술연구소 논문지 Vol.19 No.2
The main problems in photovoltaic performance measurement arises from the fact that solar cells have a highly selective spectral response and are, therefore, very sensitive to the spectral composition of the incident radiation. Outdoors, this varies considerably with location, weather, time of year and time of day, Indoors, it depends on the type of simulator used and it can change as the equipment ages. Unless measurement procedures take account of these variations and other difficulties, such as the marked temperature dependence of solar cell, the results can be grossly erroneous. Performance rakings of the same module by laboratory have been know to disagree by as much as 20%.
최연옥,이열선,서진연,한승조,조금배 조선대학교 동력자원연구소 1997 動力資源硏究所誌 Vol.19 No.1
A complete computerized system for the characterization and performance testing of photovoltaics(PV) modules under natural sunlight and ambient condition was designed. I-V characteristics of PV module provides on essential diagnostic means in assessing the performance and internal cell parameters of PV module depends on its basic materials, manufacturing technology and operating environmental conditions. I-V curves derived from PV modules refect to a large extent the physical properties and their expected performance. In this paper, Electrical performance measurement and evaluation methods for solar cell module by MOSFET variable Load were studied. Also, Mathematical model and theory of solar cell associated with the photovoltaic effect has been discribed.
최연옥,조금배 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.2
A single-phase PWM current source rectifier with a neutral leg is presented and throughly analyzed in this paper. This novel topology is implemented by adding an extra leg a step-down single phase PWM space vector modulation method to reduce the dc output voltage harmonics. The PWM pattern generation need a digital system. As compared with a conventional single-phase PWM rectifier, over 20% improvement of the total harmonics distortion in the output voltage can be obtained. Different SVM techniques are analyzed for this PWM rectifier and simulation results are presented.
Anti-Windup기법을 이용한 유도전동기의 벡터제어에 관한 연구
최연옥,조금배 조선대학교 전자정보통신연구소 2001 電子情報通信硏究所論文誌 Vol.4 No.1
The rotor flux vector is used to calculate the flux angle for coordinate transformation, feed the control signal for d-axis controller and synthesize the de coupling voltage for independent d and q axis currents control. Various methods are developed to find the flux vector of induction motor for direct rotor field oriented control; direct measurement and estimation methods. This paper is on speed control of induction motor using space vector PWM. Vector control which controls independantly flux and torque current component in order to drive induction motor, is applied for driving motor. In this paper, the performance of the proposed anti-windup control is verifed by experimentation under various conditions with an induction motor drive system composed a high speed DSP controlled, an AC-DC-AC converter and induction motor.
확장된 칼만필터를 이용한 유도전동기의 센서리스 벡터제어
최연옥,정병호,조금배 조선대학교 에너지.자원신기술연구소 2000 에너지·자원신기술연구소 논문지 Vol.22 No.1
Using Observer, on the sensorless vector control system is a novel techniques for modern induction motor control. In this paper, a speed estimation algorithm of an induction motor using an extended kalman filter was proposed. Extended kalman filter can solve the problem, that have steady state error of estimated speed in flux and slip estimation method. The extended Kalman filter is employed to identify the speed of an induction motor and rotor flux based on the measured quantities such as stator current and DC link voltage. In order to confirming above proposal, computer simulation carried out control drives for using Matlab Simulink and show the effectiveness of the control drives for induction motor speed estimation.
반응표면분석법에 의한 동충하초 첨가 증편 제조의 최적화
박금순,윤광섭,황성희,조현정,김정숙 한국조리과학회 2003 한국식품조리과학회지 Vol.19 No.4
To optimize the preparation process of Jeung-Pyun, an experiment was derived, using a central composite design, to find the optimal mixing conditions. The addition of Paecilomyces japonica powder, the volume of Tak-Ju and the second fermentation time were independent variables, with the pH, volume, color, sensory and texture properties of the Jeung-Pyun selected as response variables. As the Paecilomyces japonica powder and fermentation time were increased, the b values and volume after the second fermentation also increased. The color of the Jeung-Pyun became deeper with increases in the Paecilomyces japonica powder and fermentation time, and was deepest on the addition of 30% Tak-Ju. The pH increased with increasing fermentation time of the Jeung-Pyun, and on the addition of 3% Paecilomyces japonica rapidly increased more than with the other groups. The optimal mixing conditions for the best quality Jeung-Pyun, with restricted conditions above a b value of 3, a color intensity above 3, and a volume of 40㎖ and a pH of 4.02~4.04 after the second fermentation, were 4.0%, 20% and 45 mins for the Paecilomyces japonica powder, Tak-Ju and second fermentation time, respectively.
최연옥,현성복,조금배 조선대학교 에너지.자원신기술연구소 2000 에너지·자원신기술연구소 논문지 Vol.22 No.1
The noise of the most industrial universal motor are mainly caused by the electromagnetic effect. This kind of noise can be amplified by the structure itself, if the frequency components of the magnetomotive force are close to the resonance frequencies of the structure. Therefore, there must be an intermediate process which usually called structure dynamic modification to avoid this phenomenon. In order to yield the input forces for the motor, analytical forms of magnetomotive force were obtained and those were feed to do response analysis. Through these analysis, some design guide were suggested to reduce the vibration of the universal motor.
최연옥,정병호,조금배 조선대학교 전자정보통신연구소 2002 電子情報通信硏究所論文誌 Vol.5 No.1
In this paper, a direct torque control(DTC) method of an induction motor is proposed which enables constant switching frequency. The switching strategy of a conventional direct torque control scheme which is based on hysteresis comparator results in a variable switching frequency which depends on the speed, flux, stator voltage and hysteresis band of the comparator. This paper proposes a new switching strategy which determine the effective switching time on each switching period by comparing the ascending and descending torque slopes. The simulation results are presented to verify this proposed scheme.
태양광 발전시스템의 최대전력추적을 위한 DC/DC 컨버터 제어
최연옥,서진연,장용해,정삼용,조금배 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.2
Solar energy converters were used to convert the electrical energy from the solar arrays to a stable and reliable power source. The object of this paper is to analyze and design DC/DC converters of different types in a solar energy system in order to investigate the performance of the converters. A simple method which combines a discrete time control and a PI compensator is used to track the maximum power point of the solar array. The system is kept to operate close to MPPT's thus the maximum possible power transfer from the solar array is achieved. Experimental tests were carried out for buck, boost and buck-boost converters using a simple maximum power point tracking algorithm.
최연옥,이열선,조금배 조선대학교 전자정보통신연구소 2000 電子情報通信硏究所論文誌 Vol.3 No.1
Direct Torque Control(DTC) of AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement However, DTC do not show good performance at low speed range with conventional open loop stator flux observer when stator resistance varied So, authors proposed nonlinear stator flux obsever in order to flux estimation at low speed and show its simulation results