• Journal of Power Electronics
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• 제14권6호
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• pp.1217-1223
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• 2014

A novel half load-cycle worked dual input single output (DISO) DC/AC inverter is presented. The basic circuit consists of a dual buck regulator, which works in continuous current mode. The working principle of DISO DC/AC inverter has been used. The control method applied for half load-cycle worked DISO DC/AC inverter has been studied. The control effects of the open-loop proportional control and closed-loop proportional-integral control are compared by using PSIM software. The parameters are adopted in the realistic simulation and experiment test. Moreover, the waveforms, such as voltage of modulation reference signal and output voltage, were given. The simulation and experiment results proved that the half load-cycle worked DISO DC/AC inverter could achieve good performance, gain a line frequency of 50 Hz, and verify the correctness of theoretical analysis.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2005년도 전기학술대회논문집
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• pp.1005-1010
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• 2005

In this paper, it is presented a frequency modulated continuous wave radar (FMCW) for distance measurement. The frequency range is $10{\sim}11$ GHz and the sweep time of the signal is 100 ms. The test target is 0.8 m2 of metal plate. The experiment is performed in open ground and the pyramidal horn antenna of about 22 dBi gain is used. The beat frequency according to the target moving to 40 m is measured. There is a good agreement between measured and calculated results. But the resolution of the FMCW radar is not good such as about 10 cm. It is result from the nonlinear signal of voltage controlled oscillator (VCO). To improve the nonlinear characteristic of VCO, a high pass filter and phase locked loop (PLL) frequency synthesizer are included in the radar system.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.465-465
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• 2000

The paper presents the fuzzy control technique to adjust the gain schedule in the fuzzy controller. The micro computer is designed to the fuzzy controller to execute the proportional gain with the data of the error and speed command. The gain schedule is the fuzzy set which execute based on the fuzzy rule. The gain schedule from the fuzzy controller is fed to the sinusoidal pulse width modulation (SPWM) inverter for control the response and speed of the induction motor. The induction motor coupling to the DC motor and tachogenerator which DC motor as a load. The test result of the fuzzy control technique in the open loop control, it provides a good response and in the closed loop control it can control speed in the any condition of load design

• 대한기계학회논문집
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• 제19권9호
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• pp.2399-2411
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• 1995

Crane operation for transporting heavy loads inherently causes swinging motion at the loads due to crane's acceleration or deceleration. This motion not only lowers the handling safety but also slows down the handling process. To complement such a problem, Korea Atomic Energy Research Institute(KAERI) has designed several anti-swing controllers using open loop and closed loop approaches. They are namely a pre-programmed feedback controller and a fuzzy controller. These controllers are implemented on a 1-ton crane system at KAERI and their control performances are compared. Test operations show that the new controllers are superior to that of conventional cranes in terms of robustness to the disturbances and adaptation capability to the change of rope length.

• 전기학회논문지
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• 제61권12호
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• pp.1903-1910
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• 2012

This paper presents a data based low-order controller design algorithm for a linear time-invariant process with a time delay. The algorithm is composed by combining an identification step based on open loop pulse test with a low-order controller design step to obtain the entire set of controllers achieving multiple performance specifications. The initial information necessary for this algorithm are merely the width and amplitude of a rectangular pulse, a controller of four types (PI, PD, PID, first-order), and design objectives. Various parametric approaches that have been developed are merged in the controller design algorithm. The resulting controller set satisfying the design objectives are displayed on the 2D and 3D graphics and thus it is very easy for us to pick a controller inside the admissible set because we can check the corresponding closed-loop performances visually.

• 한국군사과학기술학회지
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• 제2권1호
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• pp.121-131
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• 1999

프로펠러 항공기에서는 추력효과 때문에 엔진 출력 변동시 트림 상태를 유지하기 위해서 계속적인 트림 스위치 조작을 하여야 한다. 자동러더트림장치는 고출력 터보 프롭 항공기에서 추력효과가 발생할 때 트림 상태를 유지하기 위해 러더 트림 조작에 필요한 조종사의 조종부담을 경감시키기 위해 도입된 장치이다. 본 논문은 자동러더트림장치 개발을 위한 기술적인 해석, 제어법칙에 대한 설계, 그리고 장치 적용에 따른 비행운동에 있어서의 효과를 분석한 내용이다. 자동러더트림장치의 제어 법칙은 항공기 특성 분석과 설계 요구도 및 제약 조건 등을 고려하여 설계되었고, 트림 맵을 이용하는 개루프제어 방법과 횡축 가속도를 제환 신호로 사용하여 개루프 시스템의 에러를 보상하도록 하는 폐루프 제어 방법의 통합으로 구현되었다. 설계된 제어 법칙을 이용한 자동러더트림장치를 실제 항공기에 장착하여 시험한 결과 방향축 트림을 위한 조종사의 조종부담을 효과적으로 감소시켰고, 엔진 출력이 변할 때 발생하는 순간 요우 모션도 크게 보상시킴을 확인하였다.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2004년도 제22회 춘계학술대회논문집
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• pp.376-379
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• 2004

The purpose of this work is to develop an effective active control system for combustion instabilities of premixed combustors. For the first step, the natural modes of combustion oscillation were investigated for a methane-air premixed combustor and the controls by secondary fuel injection were examined. The main premixed flame is stabilized by a swirler with orifices for secondary injection installed on the central hub. For sensing purposes, a pressure transducer and a chemiluminescence sensor were placed on the appropriate positions. The acoustic characteristics and the source of the oscillation were analyzed by those signals. To test the controllability, two methods of actuations by secondary fuel injection were examined. One is the open loop control and the other is the closed loop control. The comparison of the reduction levels of p $_{rms}$ shows that the closed loop control with a phase-shift injection performs best in this condition.ition.n.

• 한국정밀공학회지
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• 제21권8호
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• pp.143-151
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• 2004

This paper deals with the precision NURBS interpolator for wire-EDM. Previous research about OAC (Open Architecture Controller) is mostly aimed at NC cutting machines such as milling or lathes, and hence these results are inadequate to apply to wire-EDM. In contradiction to NC machines, wire-EDM operates relatively slow feed rates and based on a feedback control loop to the machining process. The 2-stage interpolation method which reflects wire-EDM specific characteristics was proposed. The constant interpolation error could be acquired through 1 st stage interpolation. Feed rate regulation was performed through 2nd stage interpolation. The suggested algorithm was implemented to test-bed PC-NC system. Computer simulations and the experimental machining were conducted.

• 한국항공우주학회지
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• 제33권3호
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• pp.47-56
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• 2005

본 논문에서는 마이크로 자이로스코프를 위한 폐루프 제어기를 설계하여 그 성능이 개선됨을 보였다. 마이크로 자이로스코프는 높은 Q값을 가지는 시스템으로 그 특성상 공진 영역에서 동작하게 되는데, 개루프로 동작할 경우 선형성, 대역폭 등의 성능에 제약이 있게 된다. 폐루프 제어기는 개루프 동작시의 이러한 제약을 극복하고 성능을 개선할 수 있도록 한다. 본 연구에서는 PD 제어기를 적용하였으며 실험 대상이 된 마이크로 자이로스코프는 서울대에서 설계하고 Bosch foundry에서 제작한 SNU-Bosch MEMS 자이로스코프를 사용하였다. 실험을 통해 폐루프 제어기의 성능을 검증한 결과 대역폭은 35Hz에서 78Hz로, 선형성은 2.07%에서 0.504%로, 바이어스 안정도는 0.066deg/sec에서 0.043deg/sec로 개선되는 것을 확인할 수 있었다.

• Nuclear Engineering and Technology
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• 제44권6호
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• pp.561-586
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• 2012

This paper describes a summary of final prediction results by system-scale safety analysis codes during the OECD/NEA/CSNI ISP-50 exercise, targeting a 50% Direct Vessel Injection (DVI) line break integral effect test performed with the Advanced Thermal-Hydraulic Test Loop for Accident Simulation (ATLAS). This ISP-50 exercise has been performed in two consecutive phases: "blind" and "open" phases. Quantitative comparisons were performed using the Fast Fourier Transform Based Method (FFTBM) to compare the overall accuracy of the collected calculations. Great user effects resulting from the combination of the possible reasons were found in the blind phase, confirming that user effect is still one of the major issues in connection with the system thermal-hydraulic code application. Open calculations showed better prediction accuracy than the blind calculations in terms of average amplitude (AA) value. A total of nineteen organizations from eleven countries participated in this ISP-50 program and eight leading thermal-hydraulic system analysis codes were used: APROS, ATHLET, CATHARE, KORSAR, MARS-KS, RELAP5/MOD3.3, TECH-M-97, and TRACE.