• 조명전기설비학회논문지
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• 제18권6호
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• pp.84-90
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• 2004

제어계에서 제어성능을 개선시키기 위해서 많은 제어기법들이 제안되어왔다. 궤환제어계에서 일반적으로 제어기의 출력이 제어대상의 입력으로 사용된다. 그러나 불필요한 잡음이 제어기의 출력에 포함된다. 그러므로 이러한 잡음을 제거하고 계의 응답특성을 개선시키기 위해서 전치보상기를 사용할 필요가 있다. 본 논문에서는 모델추종제어를 위한 전치보상기의 설계법을 I-PD 제어계에서 제안하였다. 제안한 전치보상기를 신경망으로 구현하였고, 계의 응답특성이 어떤 조건하에서 변할 때 원하는 응답이 되도록 전치보상기의 이득이 자동적으로 조정되도록 하였다.

• Journal of Power Electronics
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• 제7권2호
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• pp.146-158
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• 2007

A multi-pulse GTO based voltage source converter (VSC) topology together with a fundamental frequency switching mode of gate control is a mature technology being widely used in static synchronous compensators (STATCOMs). The present practice in utility/industry is to employ a high number of pulses in the STATCOM, preferably a 48-pulse along with matching components of magnetics for dynamic reactive power compensation, voltage regulation, etc. in electrical networks. With an increase in the pulse order, need of power electronic devices and inter-facing magnetic apparatus increases multi-fold to achieve a desired operating performance. In this paper, a competitive topology with a fewer number of devices and reduced magnetics is evolved to develop an 18-pulse, 2-level $\pm$ 100MVAR STATCOM in which a GTO-VSC device is operated at fundamental frequency switching gate control. The inter-facing magnetics topology is conceptualized in two stages and with this harmonics distortion in the network is minimized to permissible IEEE-519 standard limits. This compensator is modeled, designed and simulated by a SimPowerSystems tool box in MATLAB platform and is tested for voltage regulation and power factor correction in power systems. The operating characteristics corresponding to steady state and dynamic operating conditions show an acceptable performance.

• Journal of Power Electronics
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• 제15권4호
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• pp.994-1005
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• 2015

This paper presents a novel power control strategy for PWM current-source rectifiers (CSRs) in the stationary frame based on the instantaneous power theory. In the proposed control strategy, a virtual resistance based on the capacitor voltage feedback is used to realize the active damping. In addition, the proportional resonant (PR) controller under the two-phase stationary coordinate is designed to track the ac reference current and to avoid the strong coupling brought about by the coordinate transformation. The limitations on improving steady-state performance of the PR controller is investigated and mitigated using a cascaded lead-lag compensator. In the z-domain, a straightforward procedure is developed to analyze and design the control-loop with the help of MATLAB/SISO software tools. In addition, robustness against parameter variations is analyzed. Finally, simulation and experimental results verify the proposed control scheme and design method.

• Journal of Power Electronics
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• 제10권4호
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• pp.342-350
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• 2010

Randomizing the switching frequency (RSF) to reduce the electromagnetic interference (EMI) of switching power converters is a well-known technique that has been previously discussed. The randomized pulse position (RPP) technique, in which the switching frequency is kept fixed while the pulse position (the delay from the starting of the switching cycle to the turn-on instant within the cycle) is randomized, has been previously addressed in the literature for the same purpose. This paper presents a double-hybrid technique (DHB) for EMI reduction in dc-dc switching regulators. The proposed technique employed both the RSF and the RPP techniques. To effectively spread the conducted-noise frequency spectrum and at the same time attain a satisfactory output voltage quality, two parameters (switching frequency and pulse position) were randomized, and a third parameter (the duty ratio) was controlled by a digital compensator. Implementation was achieved using field programmable gate array (FPGA) technology, which is increasingly being adopted in industrial electronic applications. To evaluate the contribution of the proposed DHB technique, investigations were carried out for each basic PWM, RPP, RSF, and DHB technique. Then a comparison was made of the performances achieved. The experimentally investigated features include the effect of each technique on the common-mode, differential-mode, and total conducted-noise characteristics, and their influence on the converter’s output ripple voltage.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2015년도 전력전자학술대회 논문집
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• pp.467-468
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• 2015

능동형필터는 주로 비선형 부하로 부터 발생되는 정수배의 고조파를 보상하는데 응용되어 왔다. 본 논문에서는 국가핵융합연구소(NFRI)의 KSTAR 주장치의 전원공급장치인 PF MPS가 가동되면서 특이한 저차수 대역의 비정수 고조파가 발생되는데 이는 MG(motor generator)와 RPC (Reactive Power Compensator)간의 병렬공진 확대현상으로 나타나 고조파 전류의 증가, 전압왜형 상승 등 안정적인 전력계통 운영에 영향을 주고 있다. 따라서 이의 원인이 되는 특이성의 비정수 고조파를 저감시키기 위한 제어 알고리즘 개발과 모의시험에 관한 연구내용을 다루고자한다. 지금까지 개발된 알고리즘은 주로 정수배 고조파만을 대상으로 한 FFT의 일괄보상, 혹은 개별차수 보상방식이었으나 여기서는 DQ 변환 알고리즘을 채용하여 정수배 고조파는 물론 0.5차 단위의 비정수 고조파까지 제어하는 기술을 다루었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.280-283
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• 2004

This paper discribes the design concept, fabrication process and measuring result of 2.5kV Gate Commutated Thyristor devices. Integrated gate commutated thyristors(IGCTs) is the new power semiconductor device used for high power inverter, converter, static var compensator(SVC) etc. Most of the ordinary GTOs(gate turn-off thyristors) are designed as non-punch-through(NPT) concept; i.e. the electric field is reduced to zero within the N-base region. In this paper, we propose transparent anode structure for fast turn-off characteristics. And also, to reach high breakdown voltage, we used 2-stage bevel structure. Bevel angle is very important for high power devices, such as thyristor structure devices. For cathode topology, we designed 430 cathode fingers. Each finger has designed $200{\mu}m$ width and $2600{\mu}m$ length. The breakdown voltage between cathode and anode contact of this fabricated GCT device is 2,715V.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1994년도 제20회 학술대회
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• pp.54-58
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• 1994

본 연구에서는 가변용량형 사판식 액시얼 피스톤 펌프의 가변용량 시스템에 있어서 actuator piston의 가공정도와 실린더사이의 간극의 변화에 따른 응답성 및 누설용량에 끼치는 영향을 살펴보았다. 가변용량형 사판식 액시얼 피스톤 펌프는 사판의 각도를 조절함으로써 유량을 조절하게 된다. 사판의 각도조절은 actuator piston에 의해 행해지며, 가변용량부의 어느 설정압력에 도달하면, 이 actuator piston이 사판을 밀어 사판의 각도를 변화 시키게 된다. 지배방정식으로는 spool과 사판의 운동방정식과 각 chamber의 누설 유량이 있다. 이들 방정식을 \ulcorner으로써 각 부분의 운동을 해석할 수 있게 된다. 여기에서 해석이 어려운 부분은 각 계수들의 결정이며 simulation을 할 때는 이로한 계수들을 이론적으로 결정을 하게 되고, 실험을 통해 검증하도록 한다. 즉, 각 운동뷰의 감쇠계수와 각 오리피스를 통한 유량계수, 그리고 감쇠계수 등은 실험을 통해 검토한다. 실험을 통한 측정에서는 각 chamber의 압력은 각 chamber에 연결된 압력센서 3개에 의해 행해지며, 사판의 각도는 angle 센서에 의해 측정하게 된다. 그리고 actuator piston과 블럭 사이의 간극을 조절하여 누설계수를 변화시키며, 그 영향을 살펴보았다.

• 한국소음진동공학회논문집
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• 제18권11호
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• pp.1134-1142
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• 2008

In this paper, a model-based stick-slip compensation for the micro-positioning is proposed using an enhanced stick-slip model based on statistical rough surface contact model. The smart structure is comprised with PZT(lead (Pb) zirconia(Zr) Titanate(Ti)) based stack actuator incorporating with the PID(proportional-integral-derivative) control algorithm, mechanical displacement amplifier and positioning devices. For the stick-slip compensation, the elastic-plastic static friction model is used considering the elastic-plastic asperity contact in the rough surfaces statistically. Mathematical model of system for the positioning apparatus was derived from the dynamic behaviors of structural parts. PID feedback control algorithms with the developed stick-slip model as well as feedforward friction compensator are formulated for achieving the accurate positioning performance. Experimental results are provided to show the performances of friction control using the developed positioning apparatus.

• 한국정밀공학회지
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• 제21권11호
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• pp.91-98
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• 2004

TFLIM(Transverse Flux Linear Induction Motor), making its closed magnetic path with the direction of the traveling field orthogonal, had been developed to decrease an edge effect of the general induction motor. To control the levitation force and the thrust force on the secondary part of TFLIM independently, the various methodologies have been presented. When we try to achieve the independent control using only the multi-phase inputs assigned in the stator coils as an approach, in which condition we can minimize the coupling effect between two forces\ulcorner In this paper, we show the qualitative influence of a slip frequency, an ac magnitude, a dc offset superposed in the ac power, and a major parameter of TFLIM on the couple through the computer simulation. And to realize the independent motions between levitation and thrust motion without any auxiliary means fur isolation of the secondary part of TFLIM, the decouple compensator is suggested, including the experimental results.

• 한국소음진동공학회논문집
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• 제15권11호
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• pp.1303-1310
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• 2005

Stabilization error of target aiming systems mounted on moving vehicles is an important performance because the error directly affects hit Probability. In a heavy load targetaiming system, the disturbance torque comes from mass unbalance and linear acceleration is a main source of stabilization error. This study suggests an experimental design method of disturbance feedforward compensation control to improve the stabilization performance of heavy load target aiming systems. The filtered_x least square(FxLMS) algorithm is used to estimate the compensator coefficients adaptively. The proposed control is applied to a simple experimental set-up which simulates dynamic characteristics of a real target aiming system. The feasibility of the proposedtechnique is illustrated, along with results of experiments.