• Title/Summary/Keyword: Steady Performance

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High Performance Current Control Algorithm Based on Virtual DQ Synchronous Reference Frame for Single-Phase Boost PFC Converter (단상 부스트 PFC 컨버터용 가상 DQ 동기좌표계 기반 고성능 전류제어 알고리즘)

  • Kim, Hyun-Geun;Jin, Seong-Min;Lee, Sang-Hee;Lee, Su-Hyoung;Kim, Joohn-Sheok
    • The Transactions of the Korean Institute of Power Electronics
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    • v.22 no.6
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    • pp.496-503
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    • 2017
  • This study proposes a high-performance current control algorithm for a diode-bridge-type single-phase boost power factor correction (PFC) converter. The conventional asynchronous single-phase current controllers that directly control AC-type current tend to be accompanied by steady-state errors due to their poor dynamic characteristics for the transient-state, which can be attributed to bandwidth limitations and phase delays. In the proposed algorithm, an ideal current control with minimal phase delays and steady-state errors can be achieved by using a virtual DQ synchronous reference frame and by controlling the synchronous reference frame excluding the frequency component in the single-phase system. The performance of the conventional asynchronous single-phase current controller is compared with that of the proposed algorithm through simulation and experiments, and the results have confirmed the superiority of the latter.

Sliding Mode Control for Servo Motors Based on the Differential Evolution Algorithm

  • Yin, Zhonggang;Gong, Lei;Du, Chao;Liu, Jing;Zhong, Yanru
    • Journal of Power Electronics
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    • v.18 no.1
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    • pp.92-102
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    • 2018
  • A sliding mode control (SMC) for servo motors based on the differential evolution (DE) algorithm, called DE-SMC, is proposed in this study. The parameters of SMC should be designed exactly to improve the robustness, realize the precision positioning, and reduce the steady-state speed error of the servo drive. The main parameters of SMC are optimized using the DE algorithm according to the speed feedback information of the servo motor. The most significant influence factor of the DE algorithm is optimization iteration. A suitable iteration can be achieved by the tested optimization process profile of the main parameters of SMC. Once the parameters of SMC are optimized under a convergent iteration, the system realizes the given performance indices within the shortest time. The experiment indicates that the robustness of the system is improved, and the dynamic and steady performance achieves the given performance indices under a convergent iteration when motor parameters mismatch and load disturbance is added. Moreover, the suitable iteration effectively mitigates the low-speed crawling phenomenon in the system. The correctness and effectiveness of DE-SMC are verified through the experiment.

Comparing Methodology of Building Energy Analysis - Comparative Analysis from steady-state simulation to data-driven Analysis - (건물에너지 분석 방법론 비교 - Steady-state simulation에서부터 Data-driven 방법론의 비교 분석 -)

  • Cho, Sooyoun;Leigh, Seung-Bok
    • KIEAE Journal
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    • v.17 no.5
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    • pp.77-86
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    • 2017
  • Purpose: Because of the growing concern over fossil fuel use and increasing demand for greenhouse gas emission reduction since the 1990s, the building energy analysis field has produced various types of methods, which are being applied more often and broadly than ever. A lot of research products have been actively proposed in the area of the building energy simulation for over 50 years around the world. However, in the last 20 years, there have been only a few research cases where the trend of building energy analysis is examined, estimated or compared. This research aims to investigate a trend of the building energy analysis by focusing on methodology and characteristics of each method. Method: The research papers addressing the building energy analysis are classified into two types of method: engineering analysis and algorithm estimation. Especially, EPG(Energy Performance Gap), which is the limit both for the existing engineering method and the single algorithm-based estimation method, results from comparing data of two different levels- in other words, real time data and simulation data. Result: When one or more ensemble algorithms are used, more accurate estimations of energy consumption and performance are produced, and thereby improving the problem of energy performance gap.

Kurtosis Driven Variable Step-Size Normalized Least Mean Square Algorithm for RF Repeater

  • Han, Yong-Sik;Yang, Woon-Geun
    • Journal of information and communication convergence engineering
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    • v.8 no.2
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    • pp.159-162
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    • 2010
  • This paper presents a new Kurtosis driven Variable Step-Size Normalized Least Mean Square (KVSSN-LMS) algorithm to prevent repeater from oscillation due to feedback signal of radio frequency (RF) repeater. To get better Mean Square Error (MSE) performance, step-size is adjusted using the kurtosis. The proposed algorithm shows the better performance of steady state MSE. The proposed algorithm shows a better ERLE performance than that of KVSS-LMS, VSS-NLMS, NLMS algorithms.

Testing Items Change on Characteristics of Protective relays (보호계전기 특성시험기술의 시험항목 변화)

  • Jang, Byung-Tae;Lee, Nam-Ho
    • Proceedings of the KIEE Conference
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    • 2008.07a
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    • pp.161-162
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    • 2008
  • The steady state performance test for the digital protective relay using general relay test equipment has been main test methods. Because of the development of advanced power system testing equipments, dynamic performance test has been carried out additionally using a digital simulator such as RTDS(Real Time Digital Simulator). For the case of newly adopted digital protective relay with IEC 61850 and network, performance testing items need supplementing. This report displays testing items change according to newly protective relay.

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Hydro-elastic analysis of marine propellers based on a BEM-FEM coupled FSI algorithm

  • Lee, Hyoungsuk;Song, Min-Churl;Suh, Jung-Chun;Chang, Bong-Jun
    • International Journal of Naval Architecture and Ocean Engineering
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    • v.6 no.3
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    • pp.562-577
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    • 2014
  • A reliable steady/transient hydro-elastic analysis is developed for flexible (composite) marine propeller blade design which deforms according to its environmental load (ship speed, revolution speed, wake distribution, etc.) Hydro-elastic analysis based on CFD and FEM has been widely used in the engineering field because of its accurate results however it takes large computation time to apply early propeller design stage. Therefore the analysis based on a boundary element method-Finite Element Method (BEM-FEM) Fluid-Structure Interaction (FSI) is introduced for computational efficiency and accuracy. The steady FSI analysis, and its application to reverse engineering, is designed for use regarding optimum geometry and ply stack design. A time domain two-way coupled transient FSI analysis is developed by considering the hydrodynamic damping ffects of added mass due to fluid around the propeller blade. The analysis makes possible to evaluate blade strength and also enable to do risk assessment by estimating the change in performance and the deformation depending on blade position in the ship's wake. To validate this hydro-elastic analysis methodology, published model test results of P5479 and P5475 are applied to verify the steady and the transient FSI analysis, respectively. As the results, the proposed steady and unsteady analysis methodology gives sufficient accuracy to apply flexible marine propeller design.

Development of Classification Model on SAC Refrigerant Charge Level Using Clustering-based Steady-state Identification (군집화 기반 정상상태 식별을 활용한 시스템 에어컨의 냉매 충전량 분류 모델 개발)

  • Jae-Hee, Kim;Yoojeong, Noh;Jong-Hwan, Jeung;Bong-Soo, Choi;Seok-Hoon, Jang
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.35 no.6
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    • pp.357-365
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    • 2022
  • Refrigerant mischarging is one of the most frequently occurring failure modes in air conditioners, and both undercharging and overcharging degrade cooling performance. Therefore, it is important to accurately determine the amount of charged refrigerant. In this study, a support vector machine (SVM) model was developed to multi-classify the refrigerant mischarge through steady-state identification via fuzzy clustering techniques. For steady-state identification, a fuzzy clustering algorithm was applied to the air conditioner operation data using the difference between moving averages. The identification results using the proposed method were compared with those using existing steady-state determination techniques studied through the inversed Fisher's discriminant ratio (IFDR). Subsequently, the main features were selected using minimum redundancy maximum relevance (mRMR) considering the correlation among candidate features, and an SVM multi-classification model was devised using the derived features. The proposed method achieves satisfactory accuracy and robustness from test data collected in the new domain.

A Performance Improvement of NM-MMA Adaptive Equalization Algorithm using Adaptive Modulus (Adaptive Modulus를 이용한 NM-MMA 적응 등화 알고리즘의 성능 개선)

  • Lim, Seung-Gag
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.18 no.6
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    • pp.113-119
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    • 2018
  • This paper relates the AM-NM-MMA algorithm which possible to adaptive equalization performance improvement using the adaptive modulus instead of fixed modulus in the NM-MMA algorithm. The NM-MMA emerged for the tradeoff the MMA and SE-MMA algorithm characteristics, the MMA provides the less residual values in the steady state and have a slow convergence rate, the SE-MMA provides the fast convergence rate and increae the risidual values in the steady state. But the fixed modulus can not give the zero residual values in the perfect equalization state and eqaulization performance were degrade, the adaptive modulus was applied in order to reducing the residual values, and its improved performance were confirmed by simulation. For this, the equalizer output constellation, residual isi, MD, MSE, SER were used for performance index. As a result of computer simulation, the AM-NM-MMA has more good performance in equalizer output signal constellation, residual isi, MD, MSE than the NM-MMA, but not in SER performance.

A Study on Steady-state and Transient Performance Simulation of Turboprop Engine(PT6A-62) (터보프롭엔진(PT6A-62)의 정.동적 성능모사에 관한 연구)

  • 공창덕;기자영;신현기
    • Journal of the Korean Society of Propulsion Engineers
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    • v.4 no.2
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    • pp.61-70
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    • 2000
  • The performance simulation program on the turboprop engine(PT6A-62), which is a main engine of the first trainer KT-1 in republic of Korea, was developed. Characteristics of engine components were required for the steady-state performance analysis including on and off design point analysis. In most cases, these were substituted for what scaled from well known engine components characteristics with the scaling law. The developed program was compared with CASTURB program which is well known for the simulation performance analysis, such as analysis results of mass flow rate, compressor pressure ratio, fuel flow rate, power, specific fuel consumption ratio and turbine inlet temperature in the following four cases, to evaluate whether the developed program is acceptable or not. The first case was the sea level static standard condition and other cases were considered with various flight Mach numbers, altitudes. After verifying the developed program, the partload performance analysis was carried out. Transient performance analysis for various fuel schedules were performed. When the fuel step increase of 0.1sec was performed, the overshoot of the compressor turbine inlet temperature occurred. However, the fuel ramp increase for longer than 0.1sec time was performed, the overshoot could be eliminated.

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Performance Evaluation of FC-MMA and RMMA Algorithm for Adaptive Equalization in 2-dimensional QAM Signals (2차원 QAM 신호에서 적응 등화를 위한 FC-MMA와 RMMA 알고리즘의 성능 평가)

  • Lim, Seung-Gag;Kang, Dae-Soo
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.16 no.5
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    • pp.91-97
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    • 2016
  • This paper evaluates the equalization algorithm of FC-MMA (Fast Convergence-Multi Modulus Algorithm) and RMMA (Region based Multi Modulus Algorithm) for the compensation of intersymbol interference which is due to the distortion of communication channel. In order to obtain the error signal for adaptive equalization, the FC-MMA use the modified dispersion constant considering the number of signal symbol, the RMMA separates the 4 region which every symbol points are located, then reduce the symbol point based on this region into constant modulus symbol point. By applying the different principle in order to get the error signal for the updating the tap coefficient of adaptive equalizer, it has the different equalization performance by these error signal. The computer simulation was performed in order to compare the different equalization performance in this paper. The performance index includes the output signal constellation, the residual isi and maximum distortion that is for the convergence characteristics, the SER. As a result of computer simulation, RMMA has more good performance in the residual isi, maximum distortion after in steady state and SER performance than FC-MMA, but not in convergence speed to reach the steady state.