Soft Switching 방식을 이용한 Active Clamp Mode Forward Converter 설계

원충연,유동욱,김덕헌,김학성 成均館大學校 科學技術硏究所 1992 論文集 Vol.43 No.2

In recent years, a trend of DC-DC converter is studied mainly quasi resonant converter and multi resonant converter such as resonant type. But by using zero voltage and zero current method, these converter have voltage and current stress in the circuits. So the purpose of this paper is to reduce voltage and current stress, and to increase efficiency (about 5∼10%) rather than above converters. Experimental results show that active clamp mode PWM switching forward converter has minimum switching loss and conducting loss. The test results verify the simulation performance.

초퍼제어-직류전동기의 PSPICE 컴퓨터 시뮬레이션

元忠淵,梁承浩,金德憲,金世燦 成均館大學校 科學技術硏究所 1992 論文集 Vol.42 No.2

In this paper, the authors describe the equivalent circuit for a DC motor in consideration of both magnetic saturation and armature reaction phenomena. To develop DC motor model in PSPICE is to eliminate the gap between drive electronics and models of driven machine. On the basis of these results the dynamic characteristics of a MOSFET chopper controlled DC series motor are investigated by PSPICE simulation and experiment.

전력전자 PSPICE 컴퓨터 시뮬레이션을 위한 스위치 모델

元忠淵,金淵俊,金世燦,金德憲 成均館大學校 科學技術硏究所 1990 論文集 Vol.41 No.2

PSPICE is widely used in analysis of general circuit and simulation in electric and electrical field is applied to power electronics circuit. The circuits used with thyristors will add significant complexity to PSPICE analysis, it is important that the thyristor model be as simple as possible. In order to solve this problem, an ideal voltage controlled switch and an ideal current controlled switch were added as circuit elements. Two typical power electronics circuits simulation using PSPICE program presented.

Gu¨k 컨버어터에 의한 태양광 발전 시스템에 관한 연구

元忠淵,兪東旭,金學成 成均館大學校 科學技術硏究所 1992 論文集 Vol.42 No.2

The photovoltaic modules have each maximum power point, which depending on the intensity of sunlight, modules temperature and etc. Cu¨k converter is used to obtain the maximum charging power from photovoltaic modules to storage batteries. This paper proposed to a new tracking control method by detecting its current and voltage in photovoltaic power generation system controlled by microprocessor, in order to operate at the maximum power point tracking(MPPT) even if the sunlight and the temperature are validity of proposed MPPT method is verified by the simulations.

신경회로망을 이용한 정현파 밴드 히스테리시스 전류 제어기

元忠淵,梁承浩,金世燦,金學成 成均館大學校 科學技術硏究所 1993 論文集 Vol.44 No.1

Current-controlled PWM inverter offers substantial advantages in improving motor system dynamics in high-performance ac drive systems under vector control. Among the various current control techniques, fixed band hysteresis current control has been widely used. A hysteresis controller employing sinusoidal bands has been reported in recent years. In this paper new current control schemes based on neural network for PWM inverter are described, Four types of controllers have been studied and their performance compared with each other. Finally, relevant simulation results are shown to prove the effectivness of the proposed current control scheme.

전류 제어형 PWM 인버어터에 의해 구동되는 유도전동기 서어보 운전시스템의 고성능 제어에 관한 연구

元忠淵,金泰勳 成均館大學校 科學技術硏究所 1989 論文集 Vol.40 No.1

In this paper, the vector control or the field oriented control system of current controlled PWM inverter fed induction motor servo drive system is proposed to obtain good dynamic response. The good dynamic response, however, depends on the controllability of the stator current. In this paper, an optimum current control strategy is proposed, which provides better dynamic response for current control. In order to realize this aim, the authors are adopted the current controlled PWM inverter with hysteresis controller. The controller produces a PWM Voltage waveform based on a comparison of the actual phase currents with a reference current. The time optimal controller is used as a outer loop of the vector control loop to regulate position and/or speed of induction motor. A simple set of switching trajectory is easily obtained by solving a second order state equation. The validity of the optimal control strategy is verified by digital simulation.

퍼지보상기를 이용한 유도전동기의 속도제어에 관한 연구

김연충,원충연,이상석,김영렬 성균관대학교 1998 학술회의지원논문목록집 Vol.1998 No.-

The conventional PI controller has been widely used in industrial applications. If a PI control gain is selected suitable. the PI controller shows very good control performance. But it is very difficult to find the optimal PI control gain. Therefore, in this paper, the 4-rule based fuzzy logic modifier of the conventional PI controller are presented. The fuzzy logic modifier which exhibits a stabilizing effects on the closed-loop system. has good robustness regarding the improperly tuned PI controller. The simulation are performed to verify the capability of proposed control method on vector controlled induction motor drive system.

Walsh-Fourier변환을 사용한 PWM인버어터의 새로운 고조파 제거방법에 관한 연구

安斗守,元忠淵,李海基,金泰勳 成均館大學校 科學技術硏究所 1989 論文集 Vol.40 No.2

The thesis presents the problem of new harmonic elimination method of P\V\i inverter f d induction motor system using walsh series. In other words, this thesis presented technique of the selective harmonics elimination (SHE) by W-FT series in three phase PWM inverter output waveform. A microprocessor(8086 CPC)-controlled three phase induction motor system in order to verify this algorithm is presented. It is designed for a three output voltage in the 1∼60Hz inverter with the 5th and 7th harmonics, 5th, 7th, 11th, and 13th harmonics eliminated, and with the fundamental wave amplitude proportional to the output frequency. As the results, the performance of the proposed method could eliminate the harmonics and reduce computation time which determines switching pattern. In inverters, dead time circuits are inserted in the switching signals to prevent the dc link shortage. This causes the "dead-time effect", the fundamental voltage drop and the generation of low order harmonics, this thesis is deals with quantative prediction of dead-time effect and its compensation in PWM inverters. The performance of the compensation circuits is conformed through the sir,.-elation and the experiment. In the future, the proposed PWM pattern by W-FT series, is effective not only to the induction but also to the other electromagnetic machine such as volta e regulator, UPS.

자기학습형 뉴로―퍼지 제어기의 학습에 관한 연구

梁承浩,元忠淵 成均館大學校 科學技術硏究所 1994 論文集 Vol.45 No.1

In this study, a Self-Learning Neuro -Fuzzy Controller is presented. Due to the fuzzy controller property, the designing problems of fuzzy if then rules, membership and inference methods are very complex task. Thus in this paper we proposed the Neuro-Fuzzy Networks composed by Sugeno and Takagi's fuzzy inference method and learned by using temporal back propagation algorithm. The proposed method can refine automatically the fuzzy if-then rules without human expert's knowledges. The induction motor servo system is used to de-monstrate the effectiveness of the proposed control scheme and the feasibility of the acquired neuro-fuzzy controller. All results are supported by simulation.

신경회로망을 이용한 유도전동기 속도제어

金世澯,元忠淵 成均館大學校 科學技術硏究所 1995 論文集 Vol.46 No.1

The neural network control can roughly be classified as the direct control and indirect control schemes. When using direct control scheme, there is need to know the Jacobian of plant. However when the plant is ill-defined, we can not get Jacobian of plant. Rather than using the direct control scheme, an indirect control scheme is alternative. This scheme is applicable even when the plant is ill-defined. but this scheme requires two neural network : namely Neural Network Controller and Neural Network Emulator. In this study indirect control scheme is adopted for Induction Motor speed control. A back propagation algorithm is used to train neural network controller and. emulator. The simulation results show that this neural network system can provide good dynamical responses.