• Title/Summary/Keyword: Fixed Grid System

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The Instantaneous Phase-Tracking in PLL using the DFT Algorithm (DFT 알고리즘을 이용한 PLL의 순시 추종)

  • Kim, Youn-Seo;Yang, Oh
    • Journal of the Institute of Electronics Engineers of Korea SC
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    • v.45 no.6
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    • pp.141-148
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    • 2008
  • An utility voltage information, including the frequency, phase angle and amplitude is very important in many industrial systems. The grid-connected photovoltaic system in the limelight as alternative energy needs utility voltage information such as frequency, phase angle and magnitude to connect the grid-line. In this paper, it proposes the instantaneous phase-tracking in PLL that uses the frequency from the utility voltage as a sync signal and locks the phase with compensation for phase difference from DPT algorithm. It also proposes not only DFT algorithm execution by every sample not by one period, but also phase-tracking method in a wide range of frequency not a fixed one. This paper shows the feasibility and the usefulness of the proposed methods through the computer simulation and the experiment.

3D Detection of Obstacle Distribution and Mapping for Walking Guide of the Blind (시각 장애인 보행안내를 위한 장애물 분포의 3차원 검출 및 맵핑)

  • Yoon, Myoung-Jong;Jeong, Gu-Young;Yu, Kee-Ho
    • Journal of Institute of Control, Robotics and Systems
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    • v.15 no.2
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    • pp.155-162
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    • 2009
  • In walking guide robot, a guide vehicle detects an obstacle distribution in the walking space using range sensors, and generates a 3D grid map to map the obstacle information and the tactile display. And the obstacle information is transferred to a blind pedestrian using tactile feedback. Based on the obstacle information a user plans a walking route and controls the guide vehicle. The algorithm for 3D detection of an obstacle distribution and the method of mapping the generated obstacle map and the tactile display device are proposed in this paper. The experiment for the 3D detection of an obstacle distribution using ultrasonic sensors is performed and estimated. The experimental system consisted of ultrasonic sensors and control system. In the experiment, the detection of fixed obstacles on the ground, the moving obstacle, and the detection of down-step are performed. The performance for the 3D detection of an obstacle distribution and space mapping is verified through the experiment.

Control of Power Quality Using a High Voltage STATCOM for the Integration of Large Scale Wind Power Plant (고전압 무효전력 보상기를 사용한 대규모 풍력발전 설비의 전력 품질 보상)

  • Kim, Jihong;Song, Seungho;Jeong, Seunggi
    • New & Renewable Energy
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    • v.8 no.4
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    • pp.13-20
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    • 2012
  • This paper describes a transformerless static synchronous campensator (STATCOM) system based on cascade H-bridge multilevel inverter with star configuration. It is designed not only for the dynamic and continuous compensation of the reactive power but also for the improvement of power quality of existing wind power plant. Especially, when the induction generator of wind turbine is directly connected to the grid, reactive power are occurred by exiting current. so a reactive power compensation system based on the cascade H-bridge multilevel STATCOM is proposed because the output power quality and controllability of reactive power are required by grid code in many different countries. Using various The proposed reactive power control strategy using a STATCOM is compared with the conventional scheme using fixed-size of capacitor bank through various simulation results.

A Study about Grid-Connected Wind Power Generation System (계통연계 풍력발전 시스템에 관한 연구)

  • Cho, Moon-Taek;Hwang, Lak-Hun;Kim, Young-Soo;Na, Seung-Kwon;Song, Ho-Bin;Kim, Yeal-Chung
    • Proceedings of the KIEE Conference
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    • 2007.07a
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    • pp.1238-1240
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    • 2007
  • The wind force development system is applying variableness inside system recently. High-capacity system performs blade pitch check and main point check, but because pitch angle is fixed in case of capacity system, development efficiency drops. Must do to achieve variableness inside control about change of manners to be acted in maximum electric power point hereupon. Treatise that see hereupon proves this theoretically, and proved validity through 400 [W] experiments.

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Stability Analysis of Mooring Lines of a Submersible Fish Cage System Using Numerical Model

  • Kim, Tae-Ho;Hwang, Kyu-Serk
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.5
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    • pp.690-699
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    • 2011
  • A numerical model analysis was performed to analyze the stability of the mooring lines of an automatic submersible fish cage system in waves and currents. The fish cage system consisted of a 12-angled rigid frame, net cage, cover net, 12 upper floats, 12 tanks(for fixed and variable ballast), mooring lines, anchors, and a control station. Simulations were performed with the cage at the surface of the water and at a depth of 20 m. A Morison equation type model was used for simulations of the system in two configurations. The force parameters described both regular and random waves, with and without currents, and their values were input to the model. Mooring tension calculations were conducted on the mooring lines, grid lines and lower bridle lines of the cage. The stability of the mooring lines was checked under both static and dynamic conditions.

Variable Step-Size MPPT Control based on Fuzzy Logic for a Small Wind Power System (소형풍력발전시스템을 위한 퍼지로직 기반의 가변 스텝 사이즈 MPPT 제어)

  • Choi, Dae-Keun;Lee, Kyo-Beum
    • The Transactions of the Korean Institute of Power Electronics
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    • v.17 no.3
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    • pp.205-212
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    • 2012
  • This paper proposes the fuzzy logic based variable step-size MPPT (Maximum Power Point Tracking) method for the stability at the steady state and the improvement of the transient response in the wind power system. If the change value of duty ratio is set on stability of the steady state, MPPT control traces to maximum power point slowly. And if the change value is set on improvement of the transient response, the system output oscillates at the maximum power point. By adjusting the step size with fuzzy logic, it can be improved the MPPT response speed and stability at steady state when MPPT control is performed to track the maximum power point. The effectiveness of the proposed method has been verified by simulations and experimental results.

Design of Robust Adaptive Fuzzy Controller for Uncertain Nonlinear System Using Estimation of Bounds for Approximation Errores and Dynamic Fuzzy Rule (근사화 오차의 유계상수 추정과 동적인 퍼지규칙을 이용한 비선형 계통에 대한 강인한 적응 퍼지 제어기 설계)

  • Park, Jang-Hyun;Seo, Ho-Joon;Park, Gwi-Tae
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2308-2310
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    • 2000
  • In adaptive fuzzy control, fuzzy systems are used to approximate the unknown plant nonlinearities. Until now, most of the papers in the field of controller design for nonlinear system using fuzzy systems considers the affine system with fixed grid-rule structure. This paper considers general nonlinear systems and dynamic fuzzy rule structure. Adaptive laws for fuzzy parameters and fuzzy rule structrue are established so that the whole system is stable in the sense of Lyapunov.

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Modeling and Analysis of Control Scheme for Voltage Source Inverter Based Grid-connection of Wind Turbine (전압원인버터를 이용한 계통연계형 풍력발전의 출력제어 모의 및 해석)

  • 김슬기;김응상
    • Journal of Energy Engineering
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    • v.12 no.2
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    • pp.154-163
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    • 2003
  • Grid connection essentially requires a wind energy conversion system (WECS) to not only supply adequate power responding to constantly varying wind speed but also provide a specified level of voltage magnitude and frequency that is acceptable in the electric power network. To satisfy such requirements, appropriate control schemes of a wind turbine to be connected to the power grid should be employed. This paper presents an output control strategy of a grid-connected wind power generation, which consists of a fixed-pitch wind turbine, a synchronous generator and a AC-DC-AC component with a voltage source inverter built in, and performs modelling and analysis of the strategy using PSCAD/EMTDC, an electromagnetic transient analysis software. Real power output control of the voltage source inverter is implemented to extract the maximum energy from wind speed inputted through wind blades and reactive power control, to keep the terminal voltage of WECS at a specific level. SPWM switching method is used to reduce the harmonics and maintain 60 ㎐ of the output frequency. The wind turbine performance and output corresponding to wind variation and the terminal load change is simulated and analysed.

Comparison of PI and PR Controller Based Current Control Schemes for Single-Phase Grid-Connected PV Inverter (단상 계통 연계형 태양광 인버터에 사용되는 PI 와 PR 전류제어기의 비교 분석)

  • Vu, Trung-Kien;Seong, Se-Jin
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.11 no.8
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    • pp.2968-2974
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    • 2010
  • Nowadays, the PV systems have been focused on the grid connection between the power source and the grid. The PV inverter can be considered as the core of the whole system because of an important role in the grid-interfacing operation. An important issue in the inverter control is the load current regulation. In the literature, Proportional Integral (PI) controller, which is normally used in the current-controlled Voltage Source Inverter (VSI), cannot be a satisfactory controller for an AC system because of the steady-sate error and the poor disturbance rejection, especially in high-frequency range. Compared with conventional PI controller, Proportional Resonant (PR) controller can introduce an infinite gain at the fundamental frequency of the AC source; hence it can achieve the zero steady-state error without requiring the complex transformation and the de-coupling technique. Theoretical analyses of both PI and PR controller are presented and verified by simulation and experiment. Both controller are implemented in a 32-bit fixed-point TMS320F2812 DSP processor and evaluated on a 3kW experimental prototype PV Power Conditioning System (PCS). Simulation and experimental results are shown to verify the controller performances.

The Discipline of the Dom-ino Frame and the Regulating Line - A Study of Le Corbusier's Villa La Roche-Jeanneret and Villa Stein-de Monzie - (르 꼬르뷔제 건축에서 돔-이노 프레임과 규준선의 기율 - 라 로쉬-잔느레 주택과 가르쉬 주택을 중심으로 -)

  • Pai, Hyung-Min;Hyun, Myung-Seok
    • Journal of architectural history
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    • v.12 no.1 s.33
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    • pp.25-41
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    • 2003
  • This paper is a study of Le Corbusier's trace regulateur of the 1920s, particularly its role in the design of the Villas La Roche-Jeanneret and Stein-de Monzie. It proceeds on the basis of the following three themes: first, the relation between the regulating line and the dom-ino frame; second, its status as a proportional device based not on a module system but one that defines relations; third, its function as an essential practical device in the design process. In the Villa La Roche-Jeanneret, the embedded horizontal planes of the dom-ino frame were constant, but the vortical lines of the columns were altered according to the changes in plan. Initially, a left-hand bay window formed a symmetry with the right-hand bay window, the only constant in the design process. With subsequent changes, mullion sections of the horizontal window and roof elements came to provide the reference points for the regulating line. Eventually, a regulating line different from the one that controlled the bay window and the elongated volume came to control the entrance hall of Villa La Roche, resulting in three different kinds of regulating lines in the final version. In contrast to the Villa La Roche-Jeanneret, a singular and consistent regulation line was anticipated in the earliest design stages of the Villa Stein-de Monzie. The repetition of its A:B grid and the standard $2.5m{\times}1.0m$ sliding window determined the proportions of both its plan and elevation, and thus the regulating line became 'automatic,' losing its viability as a practical tool. Though the regulating titles of the La Roche-Jeanneret look as if they were an afterthought, drawn after the design was complete, they were most active, requiring tenacity and discipline in their application. On the other hand, the seemingly 'redundant' regulating line of the Villa Stein-de Monzie gains its raison d'etre from the dom-ino frame. Its cantilevers and uninterrupted horizontal window could be used in decisive fashion because of the guarantee that the correct proportion would always be maintained. Thus we discover that Le Corbusier's discipline of the 1920s had a certain spectrum of flexibility. His 'parti' ranged from the extremely loose and malleable grid of the Villa La Roche-Jeanneret to the fixed grid of the Villa Stein-de Monzie. In different ways, these projects retain the tension between the dom-ino frame and the regulating line. For Le Corbusier, as much as the grid was an object with fixed attributes, it was also an active medium manipulated by the will of the architect.

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