• Proceedings of the KIEE Conference
• /
• 2008.07a
• /
• pp.2281-2282
• /
• 2008

전력계통에서 전압을 안정시키고 계통의 안정도를 증진시키기 위해 송전시 발생하는 무효전력을 보상하는 방법으로 SVC(Static Var Compensator, 정지형 무효전력보상기)를 사용한다. SVC를 TCR(Thyristor Controlled Reactor)과 FC(Fixed Capacitor)필터, 그리고 스너버(Snubber)회로를 사용하여 모델링하고 이 모델을 EMTP를 이용하여 시뮬레이션함으로써 그 결과를 통해 SVC가 전력계통의 무효전력을 보상함을 알아본다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.25 no.11B
• /
• pp.1895-1902
• /
• 2000

이 논문에서는 AD 변화기의 앞에 설치되는 샘플-앤드-홀드 회로의 비선형성을 보상하기 위해 신경 회로망 기법과 볼테라 급수 모델을 직접적으로 적용하는 기법을 제안한다. 제안하는 기법들의 성능을 비교하기 위해, 볼테라 급수 모델에 기반을 둔 전통적인 p차 역산 방식의 결과와 비교 검토한다. 비교 검토를 위해서는 모노-톤과 투-톤 신호를 사용하여 출력의 고조파 및 혼변조 레벨을 살펴보았다. p차 역산 방식이 역 시스템을 구하는 것이라면 제안하는 기법들은 최적화 기법에 바탕을 두고 있다고 할 수 있다. 결과를 보면 어떤 한 방식이 다른 방식보다 성능이 월등하다고 할 수 없는데, 그 이유는 각 방식마다 나름대로의 장단점을 갖고 있기 때문이다. 보상 방식의 선택은 신호의 통계적 성질, 신호 레벨, 비선형성의 정도 등을 고려해야 한다.

• Journal of IKEEE
• /
• v.25 no.2
• /
• pp.261-266
• /
• 2021

This paper suggests design methodology for thermal infrared data correction algorithms considering environmental temperature variations. First, a thermal infrared measurement model is suggested by a parameter-dependent first-order input-output equation using the relationship between infrared measurement data and model environmental parameters. In order to compensate the influence of environmental temperatures on infrared data, a compensation function is identified. Through experiments, the proposed algorithm is shown to reduce the influence of environmental temperatures on the infrared data effectively.

• Journal of the Institute of Electronics and Information Engineers
• /
• v.51 no.1
• /
• pp.202-208
• /
• 2014

Friction force on robot systems is highly nonlinear and especially disturbs precise control of the robots at low speed. This paper deals with the dynamic friction compensation problem of a well-known one-link benchmark robot system. We consider the LuGre model because the model can successfully represent dynamic characteristics and various effects of friction phenomenon. The proposed controller is constructed as two parts. An adaptive controller based on dual observers is used to estimate and compensate the dynamic friction. In order to attenuate the friction estimation error and other disturbances, PI observer is additionally designed. Through the computer simulations with the benchmark system, this paper first examines the effects of nonlinear dynamic friction on the control performance of the benchmark robot system. Next, it is shown that the control performance against the dynamic friction is improved by using the proposed controller.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.10 no.2
• /
• pp.152-160
• /
• 2000

This paper addresses the analysis and design of fuzzy-model-based controller for nonlinear systems using extended PDC and optimal pole-placement schemes. In the design procedure, we represent the nonlinear system using a Takagi-Sugeno fkzy model and formulate the controller rules by using the extended parallel distributed compensator (EPDC) and construct an overall fuzzy logic controller by blending all local state feedback controllers with an optimal pole-placement scheme. Unlike the commonly used parallel distributed compensation technique, by blending a newly extended parallel distributed compensator and the optimal poleplacement schemes, we can design not only a local stable k z y controller but also an overall stable fuzzy controller to perform the tacking control objective. Furthermore, a stability analysis is carried out not only for the fuzzy model but also for a real nonlinear system. Finally. the effectiveness and feasibility of the proposed fizzy model-based controller design method has been shown through a simulation example.

• The Journal of the Acoustical Society of Korea
• /
• v.27 no.4
• /
• pp.191-199
• /
• 2008

In this paper, we propose a MWF-PMC noise processing method which enhances the input speech by using Mel-warped Wiener Filtering (MWF) at pre-processing stage and compensates the recognition model by using PMC (Parallel Model Combination) at post-processing stage for speech recognition in noisy environments. The PMC uses the residual noise extracted from the silence region of enhanced speech at pre-processing stage to compensate the clean speech model and thus this method is considered to improve the performance of speech recognition in noisy environments. For recognition experiments we dew.-sampled KLE PBW (Phoneme Balanced Words) 452 word speech data to 8kHz and made 5 different SNR levels of noisy speech, i.e., 0dB. 5dB, 10dB, 15dB and 20dB, by adding Subway, Car and Exhibition noise to clean speech. From the recognition results, we could confirm the effectiveness of the proposed MWF-PMC method by obtaining the improved recognition performances over all compared with the existing combined methods.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2003.10a
• /
• pp.287-287
• /
• 2003

• Journal of the Korean Society for information Management
• /
• v.10 no.1
• /
• pp.53-63
• /
• 1993

The conventional fuzzy set model has been criticized as a retrieval model because the MIN and MAX operators have the properties adverse to effective calculation of document values. Since the first introduction of fuzzy set theory a variety of fuzzy operators have been developed, which can replace the MIN and MAX operators. We analyze their behavioral aspects of generating document values, and propose the enhanced fuzzy set model based on a class of fuzzy operators called positively compensatory operators. We also show through performance experiments that the proposed fuzzy set model provides higher retrieval effectiveness.

• The Transactions of the Korean Institute of Power Electronics
• /
• v.10 no.3
• /
• pp.219-225
• /
• 2005

In this paper, a new discrete-time small signal model of an average current mode control is proposed to predict the inductor current responses. Compared to the peak current mode control, the analysis of the average current mode control is difficult because of its presence of an compensation network. By utilizing sampler model, a new discrete-time small signal model is derived and used to predict the behaviors of an inductor current of average current mode control employing generalized compensation networks. In order to show the usefulness of the proposed model, prediction results of the proposed model are compared to those of the circuit level simulator, PSIM and experiment.

• Proceedings of the KIPE Conference
• /
• 2016.07a
• /
• pp.273-274
• /
• 2016

본 논문에서는 LLC 공진형 컨버터 기반 리튬 이온 배터리 충전기의 통합형 보상기를 제안하였다. 제안한 보상기는 실효 커패시턴스의 변화를 고려할 수 있는 배터리 모델 기반으로 설계되어 전 충전 구간 동안 안정적인 동작이 가능하며 정전류-정전압 (CC-CV) 충전을 하나의 보상기로 구현하여 충전 모드 변환시의 과도 특성을 가지지 않는다. 제안한 통합형 보상기의 설계는 기본파 근사법과 확장기술함수를 활용하여 진행 하였으며, LLC 공진형 컨버터와 배터리팩을 이용한 실험결과를 통하여 그 유효성을 검증 하였다.