• 전력전자학회:학술대회논문집
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• 전력전자학회 2012년도 전력전자학술대회 논문집
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• pp.258-259
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• 2012

This paper proposes a new control strategy to eliminate the harmonic components of stator current for stand-alone DFIG system feeding non-linear loads. In this method, the LSC operates as an active filter which is controlled by employing a proportional-integral and a resonant controller. And also, the stator current is used as the feedback signal for the compensator instead of the load current, so that the additional current sensor at the load side can be removed. The experiment is verified to validate the effectiveness of the proposed compensating method.

• 한국지능시스템학회논문지
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• 제21권6호
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• pp.755-760
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• 2011

본 논문은 파티클 필터(particle filter)를 이용한 레이저 내비게이션(laser navigation)의 위치측정 성능 향상에 관한 연구이다. 레이저 내비게이션은 무선항법장치(wireless navigation system)로써 무인 자율주행 장치(automatic guided vehicle)의 위치측정 및 제어에 주로 사용되며, 이는 기존의 유선유도장치(wired guidance system)들에 비해 유지보수에 유연하면서도 완전한 자율주행이 가능하다. 하지만 무선항법장치인 레이저 내비게이션은 반응속도가 느리며 고속주행 혹은 회전주행 시에 위치 정밀도가 크게 떨어지게 된다. 본 논문에서는 이와 같은 문제점을 해결하기 위해, 비선형(non-linear)/비가우시안(non-gaussian)의 시스템에서도 강인한 특성을 지닌 파티클 필터를 이용하여 위치 정밀도를 향상시키는 방법을 제안한다. 제안한 방법의 성능을 검증하기 위해, 레이저 내비게이션과 엔코더, 자이로가 장착된 지게차 AGV(automatic guided vehicle)를 사용하였으며, 제안된 방법과 상용화된 레이저 내비게이션의 위치측정 결과를 비교하였다. 실험 결과, 제안된 방법이 상용화된 레이저 내비게이션의 위치 정밀도에 비해 약 66.5% 향상됨을 확인하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 하계종합학술대회 논문집(2)
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• pp.177-180
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• 2000

This paper proposes the optimized hardware architecture for a high performance image downscaler The proposed downscaler uses non-linear digital filters for horizontal and vertical scalings. In order to achieve the optimization, the filters are implemented with multiplexer-adder type scheme and all the filter coefficients are selected on the order of two's power. The performance of the scaler is also verified by comparing with a pixel drop downscaler. The proposed scaler is designed by using the VHDL and implemented by using the IDEC-C632 0.65$\mu\textrm{m}$ cell library.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1433-1437
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• 2007

This paper describes the detection algorithm which can distinguish series arcing signal from voltage harmonics or noises produced by the operation of non-linear loads. A high pass filter with the cutoff frequency of 3 kHz is designed and it can attenuate power frequency signal to 80 dB. Series arcing phenomena is simulated to an incandescent lamp controlled by a dimmer. From the experimental results, it is confirmed that the amplitude of the filter output voltage varies at random during series arcing but the signal generated by non-linear loads appears on a regular basis. We proposed a series arcing detection algorithm using the chaotic nature of voltage signal.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2016년도 춘계학술발표대회
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• pp.743-744
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• 2016

Object tracking in video sequences is a challenging task and has various applications. Particle filtering has been proven very successful for non-Gaussian and non-linear estimation problems. In this study, we first try to develop a color-based particle filter. In this approach, the color distributions of video frames are integrated into particle filtering. Color distributions are applied because of their robustness and computational efficiency. The model of the particle filter is defined by the color information of the tracked object. The model is compared with the current hypotheses of the particle filter using the Bhattacharyya coefficient. The proposed tracking method directly incorporates the scale and motion changes of the objects. Experimental results have been presented to show the effectiveness of our proposed system.

• 전기전자학회논문지
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• 제24권2호
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• pp.570-578
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• 2020

본 논문에서는 적응 2차 볼테라 필터를 효율적으로 구현할 수 있는 새로운 방법을 제안한다. 연산량 감소를 위해 제안된 UCFD-SVF는 수렴 성능이 저하되는 단점이 있다. UCFD-SVF의 적응 필터 계수가 적응이 진행되면서 그 에너지가 급격하게 증가하지 않는다는 점을 이용하여 적응 필터 계수를 주기적으로 초기화는 방법을 제안하였다. 또한 일정한 수렴 성능을 보장하기 위해 가변적인 간격으로 적응 필터 계수를 초기화하는 방법을 제안하였고, 비정상 환경에서 우수한 수렴 특성을 가짐을 적응 시스템 확인 응용을 위한 컴퓨터 모의 실험을 통해 보였다.

• International Journal of Fuzzy Logic and Intelligent Systems
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• 제12권1호
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• pp.42-46
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• 2012

With the development of industry, more large-scale non-linear loads are added to existing power systems and they cause the serious power quality (PQ) problems to the nearby sensitive installations more and more. To protect the important loads and mitigate the impact of PQ disturbances on them, various compensating devices are installed. One of the most important control skills used in the compensating equipment at the load side is how fast they can recognize or detect the discontinuous abnormal PQ events from the normal voltage signal. This paper deals with two estimation methods for the fast detection and tracking of general PQ disturbances: Teager Energy Operator (TEO), which is a non-linear operator and used for a short time energy calculation, and Kalman Filter (KF), which is one of the most universally used estimation techniques. And it is also shown how to apply the TEO and the KF to detect the PQ disturbances such as voltage sag, swell, interruption, harmonics and voltage fluctuation.

• 항공우주시스템공학회지
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• 제11권4호
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• pp.22-29
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• 2017

비선형특성을 갖고 있는 실제 무인기용 소형터보제트엔진의 운전 중 발생하는 결함을 효과적으로 탐지하기 위한 방안에 대해 연구하였다. 이를 위해서 동적 열역학 사이클해석을 통한 비선형 동특성 모델을 도출하였다. 실제적인 운전상황의 연출을 위해 잡음특성의 평가에 부합하는 무향칼만필터를 적용하였고 필터성능이 가미된 제어기를 설계하였다. 엔진회전수 센서의 결함을 통한 엔진 결함발생을 모사하였고, 발생된 결함의 실시간적인 탐지 방안으로 연속확률비 평가기법을 도입하였다. 이를 운전 중 엔진결함탐지에 적용한 결과 분명한 결정양상을 보임으로써 매우 효과적이고 유용함을 확인하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제8권2호
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• pp.20-24
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• 2006

Recently, utility network is becoming more and more complicated and huge due to IT and OA devices. In addition to, demands of power conversion devices which have non-linear switching devices are getting more and more increased. Consequently, because of the non-linear power semiconductor devices, current harmonics are unavoidable. Sometimes those current harmonics flow back to utility network and become one of the main reasons which can make the voltage distortion. Also, it makes noise and heat loss. On the other hands, voltage sag from sudden increasing loads is also one of the terrible problems inside of utility network. In order to compensate the current harmonics and voltage sag problem, AF(active filter) systems could be a good solution method. SMES is a very good promising source due to it's high response time of charge and discharge. Therefore, the combined AF and SMES system can be a wonderful device to compensate both harmonics current and voltage sag. However, SMES needs a superconducting magnetic coil. Because of using this superconducting magnetic coil, quench problem caused by unexpected reasons have always been unavoidable. Therefore, to solve out mentioned above, this paper presents a decisive method using shunt and series active filter system combined with SMES. Especially, authors analyzed the change of original energy capacity of SMES regarding to the size of resistance caused by quench of superconducting magnetic coil.

• 전기학회논문지P
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• 제59권1호
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• pp.18-23
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• 2010

As the increasing of Non-linear load, we have been growing interest for the harmonics. Harmonics has been focused on the current component rather than voltages. Voltage harmonics can be mainly generated at the PCC with non-linear load and act on voltage unbalance. Voltage harmonics can be enlarged at the capacitor with low impedance as frequency increases. Capacitor is basically used for the power-factor compensation and sometimes as the passive filter. Small voltage of low-order acts on quite a few at the capacitor by the current increase. Capacitor has easily fall under by harmonic components. In this paper, we measured the magnitude and phase angle of asymmetrical voltage with harmonics components at the PCC and calculated with the same condition. we concluded that voltage harmonics of higher order increase each current component but have a little effect on capacitor rating.