• Journal of Power Electronics
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• 제18권5호
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• pp.1424-1433
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• 2018

This paper presents a novel space vector pulse-width modulation (SVPWM) to synthesize an arbitrary non-sinusoidal phase voltage. The key of the proposed method is that the switching vectors used to comprise the reference vectors in the ${\alpha}_1-{\beta}_1$ frame and the ${\alpha}_3-{\beta}_3$ frame are decoupled. In the ${\alpha}_1-{\beta}_1$ frame, the reference vector is comprised by near two large vectors. The corresponding vector comprised by the two vectors in the ${\alpha}_3-{\beta}_3$ frame is considered as a disturbance, which is restrained by close-loop control. In the ${\alpha}_3-{\beta}_3$ frame, there are two methods to comprise the reference vector. Method I is a near two middle vectors method. Method II uses near four vectors (two middle and two little vectors). The proposed SVPWM using decoupled switching vectors can guarantee a maximum modulation index in the ${\alpha}_1-{\beta}_1$ frame. The effectiveness of the proposed method is verified by simulated and experimental results under various operation conditions.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2011년도 제37회 추계학술대회논문집
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• pp.575-578
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• 2011

추련편향 개념은 최신의 초음속 전투기에 적용되어 사용되고 있다. 본 연구는 추력편향노즐의 성능특성을 쉴리렌기법을 이용한 충격파 가시화를 통하여 제시한다. 피치 각 변화와 피치플랩길이 변화라는 추력편향노즐의 기하학적인 특성에 따른 실험평가를 수행하고, 이러한 연구를 통하여 추력편향노즐의 초음속 유동특성을 분석하였다. 추력편향노즐의 총 추력은 편향각도가 증가함에 따라 감소되며, 추력손실이 가장 적으면서 적절한 편향 효과를 가지는 최적의 플랩 길이비가 존재한다.

• Journal of Power Electronics
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• 제16권5호
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• pp.1773-1780
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• 2016

This paper proposes a wide air-gap control method for the multi-module permanent magnet linear synchronous motor (MM-PMLSM) based on independent vector control. In particular, the MM-PMLSM consists of symmetrical multi-module and multi-phase structures, which are basically three-phase configurations without a neutral point, unlike conventional three-phase machines. In addition, there are no additional magnetic levitation windings to control the normal force of the air-gap between each stator and mover. Hence, in this paper, a dq-axis current control applying a d-q transformation and an independent vector control are proposed for the air-gap control between the two symmetric stators and mover of the MM-PMLSM. The characteristics and control performance of the MM-PMLSM are analyzed under the concept of vector control. As a result, the proposed method is easily implemented without additional windings to control the air-gap and the mover position. The effectiveness of the proposed independent vector control algorithm is verified through experimental results.

• 한국전자파학회논문지
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• 제13권8호
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• pp.777-782
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• 2002

일반적인 시간 영역에서의 레이더 신호들은 표적의 관측각에 민감하게 변화한다. 따라서 대표적인 시간영역 레이더 신호인 1차원 range profile을 이용하여 구분실험을 하는 경우에 있어서 central moments와 PCA를 결합하여 먼저 특성벡터를 추출한 후 clustering 기법에 기반한 subclass concept을 사용하는 구분기를 사용하여 넓은 관측각에서의 표적인식 성능을 향상시킨 결과들을 보여준다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 B
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• pp.1084-1087
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• 2002

This paper presents an improved fuzzy logic-based adaptive PWM technique. A fuzzy logic- based adaptive PWM technique determines the optimal output voltage vector which takes into account both direction of back-emf and direction of current error vector. This technique has a simple structure and a good level of stability, but it has disadvantages. The longer sampling period, the larger current error. Because there is no considerations of the current error magnitude of each phases. The proposed method improves the control performance by selecting the optimum switching pattern in which the magnitudes of current errors are considered introducing space vector concept. Simulation results using Matlab/Simulink show that the proposed control method reduces current error keeping the merit of previous one.

• 한국안전학회지
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• 제32권1호
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• pp.115-120
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• 2017

The aim of this study is to develop construction safety and health management cost prediction model using support vector machine (SVM). To this end, theoretical concept of SVM is investigated to formulate the cost prediction model. Input and output variables have been selected by analyzing the balancing accounts for the completed construction project. In order to train and validate the proposed prediction model, 150 data sets have been gathered from field. Effects of SVM parameters on prediction accuracy are analyzed and from which the optimal parameter values have been determined. The prediction performance tests are conducted to confirm the applicability of the proposed model. Based on the results, it is concluded that the proposed SVM model can effectively be used to predict the construction safety and health management cost.

• Journal of Advanced Marine Engineering and Technology
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• 제29권1호
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• pp.132-139
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• 2005

This paper describes the application of sliding mode control based on the variable structure control(VSC) concept for high-performance position control of an induction servo motor A design method based on external load parameters has been developed for the robust control of AC induction servo drive. Also, a slip frequency vector control with software current control technique has been adopted to achieve fast response of an induction motor drive The position control scheme is comprised of a variable structure controller and slip frequency vector control for inverter fed induction servo motor. Simulated results are given to verify the proposed design method by adoption of sliding mode and show robust control for a change of shaft inertia, viscous friction and torque disturbance.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2002년도 추계학술대회논문집
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• pp.762-766
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• 2002

This paper describes the emotion recognition algorithm using HMM(Hidden Markov Model) method. The relation between the mechanic system and the human has just been unilateral so far. This is the why people don't want to get familiar with multi-service robots of today. If the function of the emotion recognition is granted to the robot system, the concept of the mechanic part will be changed a lot. Pitch and Energy extracted from the human speech are good and important factors to classify the each emotion (neutral, happy, sad and angry etc.), which are called prosodic features. HMM is the powerful and effective theory among several methods to construct the statistical model with characteristic vector which is made up with the mixture of prosodic features

• Journal of the Korean Data and Information Science Society
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• 제28권1호
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• pp.227-235
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• 2017

When the spatial information of each location is given specifically as coordinates it is popular to use the geographically weighted regression to incorporate the spatial information by assuming that the regression parameters vary spatially across locations. In this paper, we relax the linearity assumption of geographically weighted regression and propose a geographically weighted least squares-support vector machine for estimating geographically weighted mean by using the basic concept of kernel machines. Generalized cross validation function is induced for the model selection. Numerical studies with real datasets have been conducted to compare the performance of proposed method with other methods for predicting geographically weighted mean.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 학술대회 논문집 정보 및 제어부문
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• pp.340-342
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• 2005

This paper describes the speed-sensorless vector control system of a three-phase induction motor using sliding mode flux/speed observer. The sliding mode observer estimates the rotor speed. The error between the actual and observed currents converges to zero which guarantees the accuracy of the flux observer. The convergence of nonlinear time-varying observer along with the asymptotic stability of the controller was analyzed. To define the control action which maintains the motion on the sliding manifold, an "equivalent control" concept was used. It was simulated and implemented on a sensorless indirect vector drive for 750[W] three-phase induction motor. The simulation and experimental results demonstrated the effectiveness of the proposed estimation method.