• 전기전자학회논문지
• /
• 제26권4호
• /
• pp.596-601
• /
• 2022

최근 친환경 선박 전환 추세에 따라 EGR 시스템 적용이 증가되고 있다. EGR 시스템의 주요 부품 중 하나인 EGR 블로워는 공력시스템과 이를 구동하는 e-모터 및 인버터 등으로 구성되며, 에너지밀도가 높고 효율 특성이 우수한 영구자석형 동기전동기가 적용되고 있다. 한편, EGR 블로워용 모터의 경우 국내 중소조선기자재 기업들의 개발이 활발하지만, 선박에 탑재되는 인버터는 까다로운 선급인증을 획득해야 되므로 주로 글로벌 선진기업에서 개발한 범용 인버터가 사용되고 있다. 범용 인버터는 자가 튜닝 등 편리한 구동 기능을 갖고 있지만, 최적 제어 실패 시, 사용자 입장에서 원인을 분석하기 어려운 단점이 있다. 본 연구에서는 EGR 블로워용 SPMSM의 최적제어를 위한 전류 벡터 제어 및 Tracking observer를 설계 및 검증하여 범용 인버터의 최적제어 실패원인을 분석하고자 한다.

• 전자공학회논문지
• /
• 제51권2호
• /
• pp.55-68
• /
• 2014

현대의 지하 시설물들은 보행자의 보행에 방해되지 않도록 지하에 매설 되어 있기 때문에 가시적인 확인이 어렵다. 이러한 폐색 시설물들을 다루는 건설현장에서는 시각적으로 위치를 정확히 추정하기 어렵기 때문에 작업자의 경험 또는 종이 도면 등에 의존하다 보니 침수나 붕괴의 위험에 노출되는 등 많은 문제점이 발생한다. 본 논문에서는 일반적인 건설 현장에서 폐색된 지하 시설물을 모바일을 이용한 작업자 중심의 시각화 시스템을 제안한다. 논문의 구성은 크게 3단계로 이루어 진다. 먼저, "맨홀 검출 및 특징점 추출 단계"에서는 폐색된 건축물의 기준점인 폐색되지 않는 맨홀을 검출 및 추출한다. 다음으로, "특징점 추적 단계" 에서는 이전단계에서 추출한 특징점을 추적한다. 마지막으로, "폐색 건축물 시각화 단계" 에서는 맨홀에 따라 서로 다른 지하시설물이 존재함으로 이전 단계에서 검출 및 추적된 맨홀의 위치에 모바일에 내장된 GPS 데이터를 분석하여 현장에 해당하는 폐색된 건축물인 3차원 객체를 정합 한다. 제안된 방법은 실내 환경에서 맨홀 검출과 특징점 추출 및 추적방법들의 비교 분석을 통해 최적의 방법을 적용하였으며, 실제 환경에서의 폐색된 상/하수도 배관 증강을 통해 가능성을 확인하였다. 또한, 폐색된 상하수도 등의 건축물의 증강된 3차원 결과들로부터 작업자 중심의 보다 유용한 건설 환경을 제공할 수 있다.

• Journal of Power Electronics
• /
• 제15권5호
• /
• pp.1358-1366
• /
• 2015

This study focuses on an advanced second-order sliding mode control strategy for a variable speed wind turbine based on a permanent magnet synchronous generator to maximize wind power extraction while simultaneously reducing the mechanical stress effect. The control design based on a modified version of the super-twisting algorithm with variable gains can be applied to the cascaded system scheme comprising the current control loop and speed control loop. The proposed control inheriting the well-known robustness of the sliding technique successfully deals with the problems of essential nonlinearity of wind turbine systems, the effects of disturbance regarding variation on the parameters, and the random nature of wind speed. In addition, the advantages of the adaptive gains and the smoothness of the control action strongly reduce the chatter signals of wind turbine systems. Finally, with comparison with the traditional super-twisting algorithm, the performance of the system is verified through simulation results under wind speed turbulence and parameter variations.

• Journal of Advanced Marine Engineering and Technology
• /
• 제30권6호
• /
• pp.753-759
• /
• 2006

Integrating processes are frequently encountered in process industries. In this paper, new tuning formulae of the PID controllers for set-point tracking and load disturbance rejection are presented for integrating processes involving time delay. First, the controller parameter sets are tuned using a real-coded genetic algorithm (RCGA) such that performance criterion(IAE, ISE or ITSE) is minimized. Then, tuning rules are addressed using tuned PID parameter sets. tuning model and another RCGA. The performances of the proposed rules are tested on two processes.

• International journal of advanced smart convergence
• /
• 제1권1호
• /
• pp.52-56
• /
• 2012

As inexhaustible clean energy, solar energy will be the most ideal green energy in the 21st century. The effective method to convert solar energy into electrical energy is by solar photovoltaic power generation technologies. LED Emitting Diode is a kind of component which can transform electricity into visible light. As the smart current control system for photovoltaic street lights, the proposed system has improved the battery charging and discharging mechanism to extend the lifespan and effectively controls the LED discharge current according to battery charge state and lighting.

• 전력전자학회:학술대회논문집
• /
• 전력전자학회 2006년도 전력전자학술대회 논문집
• /
• pp.222-224
• /
• 2006

To improve the drawback of LCMPPT(Limit Cycle Maximum Power Point Tracking) controller of the existing two power conversion stages, an advanced MPPT scheme of single power conversion stage is proposed in this paper. This topology is faster on the control speed by means of current control method and the system configuration is simpler. The Authors produce a battery charger by using a cost effective one-chip processor (PIC16F877A) and evaluate another application on the basis of simulation. As a result, the proposed new LCMPPT algorithm is confirmed to be stable and useful.

• International journal of advanced smart convergence
• /
• 제7권4호
• /
• pp.114-120
• /
• 2018

The purpose of this paper is to develop simulations that can be used for virtual education in dentistry. This development goal is to allow dental students to learn the necessary surgical techniques at the point of their choice, not going into the operating room, away from time, space, and physical limits. In this paper configuration, the optimization method is applied convergent, and when the operation of the VR contents is performed, the content data is extracted from the interaction analysis formed in the VR engine, and the data is processed by the content algorithm. It also computes events and dental operations generated within the 3D engine programming and generates corresponding events through data processing according to the input signal. The visualization information is output to the HMD using the rendering information. In addition, the operating room environment was constructed by studying lighting and material for actual operating room environment. We applied the ratio of actual space to virtual space and the ratio between character and actual person to create a spatial composition at a similar rate to actual space.

• 로봇학회논문지
• /
• 제18권3호
• /
• pp.260-270
• /
• 2023

We introduce a novel Visual Inertial Odometry (VIO) algorithm designed to improve the performance of thermal-inertial odometry. Thermal infrared image, though advantageous for feature extraction in low-light conditions, typically suffers from a high noise level and significant information loss during the 8-bit conversion. Our algorithm overcomes these limitations by approximating a 14-bit raw pixel histogram into a Gaussian mixture model. The conversion method effectively emphasizes image regions where texture for visual tracking is abundant while reduces unnecessary background information. We incorporate the robust learning-based feature extraction and matching methods, SuperPoint and SuperGlue, and zero velocity detection module to further reduce the uncertainty of visual odometry. Tested across various datasets, the proposed algorithm shows improved performance compared to other state-of-the-art VIO algorithms, paving the way for robust thermal-inertial odometry.

• Journal of Advanced Marine Engineering and Technology
• /
• 제39권2호
• /
• pp.159-165
• /
• 2015

Motion control schemes are generally classified into three categories (point stabilization, trajectory tracking, and path following). This paper deals with the problem which is associated with the initial deployment of a group of Unmanned Surface Vehicle (USVs) and corresponding point stabilization. To keep the formation of a group of USVs, it is necessary to set the relationship between each vehicle. A forcing functions such as potential fields are designed to keep the formation and a graph Laplacian is used to represent the connectivity between vehicle. In case of fixed topology of the graph representing the communication between the vehicles, the graph Laplacian is assumed constant. However the graph topologies are allowed to change as the vehicles move, and the system dynamics become discontinuous in nature because the graph Laplacian changes as time passes. To check the stability in the stage of deployment, the system is modeled with Kronecker algebra notation. Filippov's calculus of differential equations with discontinuous right hand sides is then used to formally characterize the behavior of USVs. The stability of the system is analyzed with Lyapunov's stability theory and LaSalle's invariance principle, and the validity is shown by checking the variation of state norm.

• Journal of Power Electronics
• /
• 제17권1호
• /
• pp.232-241
• /
• 2017

Advanced control algorithms must be used to make wind power generation truly cost effective and reliable. In this study, we develop a new and simple control scheme that employs model predictive control (MPC), which is used in permanent magnet synchronous generators and grid-connected inverters. The proposed control law is based on two points, namely, MPC-based torque-current control loop is used for the generator-side converter to reach the maximum power point of the wind turbine, and MPC-based direct power control loop is used for the grid-side converter to satisfy the grid code and help improve system stability. Moreover, a simple prediction scheme is developed for the direct-drive wind energy conversion system (WECS) to reduce the computation burden for real-time applications. A small-scale WECS laboratory prototype is built and evaluated to verify the validity of the developed control methods. Acceptable results are obtained from the real-time implementation of the proposed MPC methods for WECS.