• Title/Summary/Keyword: synchronous generator

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A Study on Excitation System for Synchronous Generator Using Two State Three Phase PWM AC/DC Converter (2단 3상 PWM AC/DC 컨버터를 이용한 동기발전기 여자제어시스템)

  • Lee, Sang-Hun;Lee, Dong-Hee;Ahn, Jin-Woo
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.3
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    • pp.96-106
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    • 2007
  • The terminal voltage of a synchronous generator is maintained by the field current control of excitation system. Generally AC/DC converter which is component of AVR(Automatic Voltage Regulator) system for excitation current control is connected to diode rectifier and DC/DC converter system. In the case of diode rectifier system of phase controlled converter as AC/DC converter have low power factor and harmonics of lower order in the line current. In this paper, two stage three phase PWM AC/DC converter is studied to solve these problems. The characteristics of a proposed converter reduces the harmonics and reactive power of the distribution line and has fast dynamic response in transient period using boost converter and current control mode buck converts. The proposed method is verified by the computer simulation and experimental results in prototype generation system.

Characteristics Analysis of Generator by Load Variation (부하변동에 따른 발전기 특성해석)

  • Kim, Jong-Gyeum
    • 한국신재생에너지학회:학술대회논문집
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    • pp.507-510
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    • 2006
  • 본 논문은 신재생에너지의 한 분야로서 청정에너지인 소수력 발전시스템 운영시 수용가 부하의 변동에 따른 발전기의 특성변화를 해석한 것이다. 모의에 사용된 동기발전기-전동기가 부하의 변동에 따라 토크, 속도, 전류 등이 어떤 영향을 받는지 전자계 과도해석 프로그램을 사용하여 나타내었다.

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Development of Generator Excitation System with Main/Standby Controller in In-chun Thermal power plant #4 (인천화력 4호기 발전기용 주/부 제어기를 갖는 정지형 여자시스템 개발)

  • 류호선;임익헌
    • Proceedings of the KIPE Conference
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    • pp.407-410
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    • 1999
  • Potential-source controlled excitation system had been developed for synchronous generator in In-Chun thermal power plant #4 by KEPRI. This paper describes the characteristics of Main/Standby control system employed analog, digital circuit devices (hybrid type) and 3 PCRs(Phase Controlled Rectifier)

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A Study on Frequency Control and Active Power Control of Wind Turbine Generation System for PMSG (PMSG 풍력발전 시스템의 출력 제어 및 주파수 제어 연구)

  • Lee, Kwang-Soo;Kim, Mun-Kyeom
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.63 no.5
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    • pp.597-607
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    • 2014
  • This paper proposes active power control and frequency support control schemes of wind turbine generation system by using modified Maximum Power Point Tracking(MPPT) of Permanent Magnet Synchronous Generator(PMSG). Most wind turbine generation system is completely decoupled from the power system and power output control with pitch control. According to the frequency deviation, however, MPPT control can not contribute to the frequency change of the power system due to its active power output control. For solving this, the de-loaded(DL) control scheme is constructed for the frequency support control, which is based on applying the active power output control in the rotor speed control of PMSG. The rotor speed by used in the proposed DL control scheme is increased more than the optimal rotor speed of MPPT, and then this speed improvement increases the saved kinetic energy(KE). In order to show the effectiveness of the proposed control scheme, the case studies have been performed using the PSCAD/EMTDC. The results show that the proposed active power output control scheme(DL control and KE discharge control) works properly and the frequency response ability of the power system can be also improved with the frequency support of wind farm.

Power Fluctuation Reduction of Pitch-Regulated MW-Class PMSG based WTG System by Controlling Kinetic Energy

  • Howlader, Abdul Motin;Urasaki, Naomitsu;Yona, Atsushi;Senjyu, Tomonobu;Saber, Ahmed Yousuf
    • Journal of international Conference on Electrical Machines and Systems
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    • v.1 no.2
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    • pp.116-124
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    • 2012
  • Wind is an abundant source of natural energy which can be utilized to generate power. Wind velocity does not remain constant, and as a result the output power of wind turbine generators (WTGs) fluctuates. To reduce the fluctuation, different approaches are already being proposed, such as energy storage devices, electric double layer capacitors, flywheels, and so on. These methods are effective but require a significant extra cost to installation and maintenance. This paper proposes to reduce output power fluctuation by controlling kinetic energy of a WTG system. A MW-class pitch-regulated permanent magnet synchronous generator (PMSG) is introduced to apply a power fluctuation reducing method. The major advantage of this proposed method is that, an additional energy storage system is not required to control the power fluctuation. Additionally, the proposed method can mitigate shaft stress of a WTG system. Which is reflected in an enhanced reliability of the wind turbine. Moreover, the proposed method can be changed to the maximum power point tracking (MPPT) control method by adjusting an averaging time. The proposed power smoothing control is compared with the MPPT control method and verified by using the MATLAB SIMULINK environment.

A Study of a Novel Wind Turbine Concept with Power Split Gearbox

  • Liu, Qian;Appunn, Rudiger;Hameyer, Kay
    • Journal of international Conference on Electrical Machines and Systems
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    • v.2 no.4
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    • pp.478-485
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    • 2013
  • This paper focuses on the design and control of a new concept for wind turbines with a planetary gearbox to realize a power split. This concept, where the generated wind power is split into two parts, is to increase the utilization of the wind power and may be particularly suitable for large scale off-shore wind turbines. In order to reduce the cost of the power electronic devices, a synchronous generator, which is driven by the planetary gear, is directly connected to the power grid without electronic converter. A servo drive, which functions as the control actuator, is connected to the power grid by a power electronic converter. With small scale power electronic device, the current harmonics can also be reduced. The speed of the main shaft is controlled to track the optimal tip speed ratio. Meanwhile the speed of the synchronous generator is controlled to stay at the synchronous speed. The minimum rated power of the servo motor and the converter, is studied and discussed in this paper. Different variants of the wind turbine with a planetary gear are also compared. The controller for optimal tip speed ratio and synchronous speed tracking is given.

Real-Time Hardware Simulator for Grid-Tied PMSG Wind Power System

  • Choy, Young-Do;Han, Byung-Moon;Lee, Jun-Young;Jang, Gil-Soo
    • Journal of Electrical Engineering and Technology
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    • v.6 no.3
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    • pp.375-383
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    • 2011
  • This paper describes a real-time hardware simulator for a grid-tied Permanent Magnet Synchronous Generator (PMSG) wind power system, which consists of an anemometer, a data logger, a motor-generator set with vector drive, and a back-to-back power converter with a digital signal processor (DSP) controller. The anemometer measures real wind speed, and the data is sent to the data logger to calculate the turbine torque. The calculated torque is sent to the vector drive for the induction motor after it is scaled down to the rated simulator power. The motor generates the mechanical power for the PMSG, and the generated electrical power is connected to the grid through a back-to-back converter. The generator-side converter in a back-to-back converter operates in current control mode to track the maximum power point at the given wind speed. The grid-side converter operates to control the direct current link voltage and to correct the power factor. The developed simulator can be used to analyze various mechanical and electrical characteristics of a grid-tied PMSG wind power system. It can also be utilized to educate students or engineers on the operation of grid-tied PMSG wind power system.

Fuzzy Applications in a Multi-Machine Power System Stabilizer

  • Sambariya, D.K.;Gupta, Rajeev
    • Journal of Electrical Engineering and Technology
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    • v.5 no.3
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    • pp.503-510
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    • 2010
  • This paper proposes the use of fuzzy applications to a 4-machine and 10-bus system to check stability in open conditions. Fuzzy controllers and the excitation of a synchronous generator are added. Power system stabilizers (PSSs) are added to the excitation system to enhance damping during low frequency oscillations. A fuzzy logic power system stabilizer (PSS) for stability enhancement of a multi-machine power system is also presented. To attain stability enhancement, speed deviation ($\Delta\omega$) and acceleration ($\Delta\varpi$) of the Kota Thermal synchronous generator rotor are taken as inputs to the fuzzy logic controller. These variables have significant effects on the damping of generator shaft mechanical oscillations. The stabilizing signals are computed using fuzzy membership functions that are dependent on these variables. The performance of the fuzzy logic PSS is compared with the open power system, after which the simulations are tested under different operating conditions and changes in reference voltage. The simulation results are quite encouraging and satisfactory. Similarly, the system is tested for the different defuzzification methods, and based on the results, the centroid method elicits the best possible system response.

A Novel Skewed-Type Iron Slot Wedge for Permanent Magnet Synchronous Generators for Improving Output Power and Reducing Cogging Torque

  • Kang, Sun-Il;Moon, Jae-Won;You, Yong-Min;Lee, Jin-Hee;Kwon, Byung-Il
    • Journal of Electrical Engineering and Technology
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    • v.10 no.1
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    • pp.243-250
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    • 2015
  • This paper proposes a novel skewed-type iron slot wedge that can improve both the cogging torque and the output power of a permanent magnet synchronous generator (PMSG). Generally the open slot structure is adopted in a PMSG due to its convenient winding work, but the high cogging torque is undesired. Firstly, an iron slot wedge was utilized to reduce the cogging torque of an open slot type PMSG. However, the output power of the machine decreased rapidly with this method. Thus, a proposed skewed type iron slot wedge is presented to improve the output power as well as the cogging torque as compared to the open slot type. Shape optimization of the skewed-type iron slot wedge is performed to simultaneously maximize the output power and reduce the cogging torque. The Kriging model based on the Halton sequence method and a genetic algorithm are used to optimize the design.