• 항공우주시스템공학회지
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• 제7권4호
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• pp.18-26
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• 2013

The technique of sliding mode control has been introduced and designed for jet engine controller. For designing the controller for controlled element, the state space model of the turbojet engine is derived in advance from the perturbation of non-linear engine dynamic equation at operation point. Based upon the jet engine model, the robust sliding mode controller is proposed associated with the optimum sliding mode function. The numerical simulation demonstrates that the designed sliding mode controller proves its effectiveness for the jet engine by showing superior control performances over the conventional PI controller with fast responses and robustness to disturbance.

• 대한전기학회논문지:전력기술부문A
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• 제52권1호
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• pp.36-43
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• 2003

This paper presents an optimal tuning method for Fuzzy Logic Controller (FLC) of current controller for HVDC using Genetic Algorithm(GA). GA is probabilistic search method based on genetics and evolution theory. The scaling factors of FLC are tuned by using real-time GA. The proposed tuning method is applied to the scaled-down HVDC simulator at Korea Electrotechnology Research Institute(KERI). Experimental result shows that disturbances are well-damped and the dynamic performances of FLC have the better responses than those of PI controller for small and large disturbances such as ULTC tap change, reference DC current change and DC ground fault.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.1146-1148
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• 1996

In this paper, uncertain parameters of the heat transfer model of a Dynamically Tuned Gyroscope (DTG) are estimated by the Recursive Least Squares (RLS) method. Also, using this model, a temperature controller for a DTG is designed. As the temperature controller, a PI controller is used. It is presented that a controller can be easily designed when the heat transfer model of a DTG is used. By simulations and experiments, it is shown that the estimated heat transfer model is appropriate and the desired performance of the temperature controller is satisfied.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 A
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• pp.261-264
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• 1993

This paper proposes an adaptive generalized predictive control with feedforward algorithm for steam generator level control in nuclear power plant. The proposed algorithm is shown that the parameters of N-step ahead predictors can be obtained using the parameters of one-step ahead predictor which is derived from plant model with feedforward. Using this property the proposed scheme is an adaptive algorithm which consists of GPC method and the recursive least squares algorithm for identifying the parameters of one-step ahead predictor. Also, computer simulations are performed to evaluate the performance of proposed algorithm using a mathematical model of PWR steam generator Simulation results show good performances for load variation. And the proposed algorithm shows better responses than PI controller does.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
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• pp.314-316
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• 1994

The operation of RC(Rod Consolidation) technology carry out highly radiation environment. It requires remote operation and automation for efficient handling and for minimizing radiation exposure to the operator. So we investigated up and down position control of shock absorber device in RC system. To verify the research experimentally, a RC system was set up and PI control method was applied. Fuzzy control method was also tested to further improve control behavior.

• 전력전자학회논문지
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• 제18권5호
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• pp.466-476
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• 2013

This paper describes a fuzzy control method to control the output voltage of the three-phase Z-source PWM rectifier. A fuzzy control system is a control system based on fuzzy logic, and the fuzzy controller uses a single input fuzzy theory with its fuzzification. Analytical structure of the simplest fuzzy controller is derived through the triangular membership functions with its fuzzification. By setting the membership functions of the fuzzy rules, fuzzy control is achieved. The PI portion of the output DC voltage controller is controlled by fuzzy method. To confirm the validity of the proposed method, the simulation and experiment were performed, The simulation is performed with PSIM and MATLAB/SIMULINK. For the experiment, we used a DSP(TMS320F28335) controller to compute the reference value and generate the PWM pulses. For the transient state performance of the output DC voltage control of Z-source PWM rectifier, the PI controller and fuzzy controller were compared, also the conventional PWM rectifier and Z-source PWM rectifier were compared. From the results, the Z-source rectifier could allow to buck or boost of the output DC voltage. Through the analysis of the transient state, we could observe that the fuzzy controller has better performance than the conventional PI controller.

• 대한기계학회논문집A
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• 제34권12호
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• pp.1917-1923
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• 2010

이 논문은 공압식 버터플라이 제어밸브를 이용한 냉각 프로세서의 모델규명 및 선행미분형 2 자 유도 PID 제어 알고리즘 개발에 대한 연구를 수행한다. 구동 제어밸브를 포함한 냉각 프로세서의 모델 구조는 시간지연을 포함한 2차 지연 시스템 형태로 주어지며, 이는 데모 플랜트로부터의 입출력 데이터를 통하여 전달함수의 형태로 규명된다. 2 자유도 PID 제어기에서 피드백 제어게인은 Kitamori 제어게인 조정법을 이용하여 설정되며, 피드포워드 제어게인은 제어 시스템의 성능을 만족하도록 하는 관점에서 결정된다. 이 논문에서 제안된 제어 알고리즘의 유용성은 컴퓨터 모의실험과 데모 플랜트의 실험을 통해 검증된다. 결과적으로 논문에서 제안된 제어 알고리즘은 기존의 1 자유도 PID 알고리즘보다 제어게인 설정이 매우 명확하고, 제어성능이 우수함을 보인다.

• 제어로봇시스템학회논문지
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• 제13권5호
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• pp.399-405
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• 2007

This paper deals with the controller for a stable walking of a humanoid robot using genetic algorithm. A humanoid robot has instability during walking because it isn't fixed on the ground, and its nonlinearities of the joints increase its instability. If controller isn't robust, the robot may fall down at the ground during walking because of its nonlinearities. To solve this problem, robust controller is required to reduce the effect of nonlinearities and to gain the good tracking performance. In this paper, motion controller that is based on fuzzy-sliding mode controller is proposed. This controller can remove the effect of the saturation by limitation of the input voltage. It also includes compensator for reducing the effect of the nonlinearity by backlash and PI controller improving the tracking performance. In here, genetic algorithm is used for searching the optimal gains of the controller. From the given controller, a humanoid robot can moved more preciously. All the processes are investigated through simulations and are verified experimentally in a real joint system for a humanoid robot.

• 전력전자학회논문지
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• 제21권1호
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• pp.58-64
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• 2016

This study presents a design method for a single-loop voltage controller that is suitable for an arbitrary waveform generator (AWG). The voltage control algorithm of AWG should ensure high dynamic performance and should attain sufficient robustness to disturbances such as inverter nonlinearity, sensor noise, and load current. By analyzing the power circuit of AWG, control limitation and control target are presented to improve the dynamic performance of AWG. The proposed voltage control algorithm is composed of a single-loop output voltage control, an inverter current feedback term to improve transient response, and a load current feedforward term to prevent voltage distortion. The guideline for setting control gain is presented based on output filter parameters and digital time delay. The performance of the proposed algorithm is proven by experimental results through comparison with the conventional algorithm.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2013년도 추계학술대회 논문집
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• pp.25-26
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• 2013

본 논문에서는 직류출력과 교류출력을 갖는 단상 Z-소스 전자변압기를 제안하였다. 제안된 시스템은 입력은 병렬로, 츨력은 직렬로 연결된 2대의 Quasi Z-소스 AC-AC 컨버터로 구성되어 있다. 교류 입력 전압에 대하여 Quasi Z-소스 AC-AC 컨버터의 출력 전압은 동상의 강압과 승압 고정 주파수 가변 전압 VVCF(Variable Voltage Constant Frequency)의 특성을 가지고 있다. 또한 Quasi Z-소스 AC-AC 컨버터의 Active 스위치 단에 벅-컨버터를 연결하여 48V 직류 전압도 동시에 출력 할 수 있다. 끝으로 PI제어된 직류 벅 컨버터에 의하여 일정한 직류전압을 출력할 수 있음을 PSIM 시뮬레이션과 실험을 통하여 확인하였다.