• Title/Summary/Keyword: synchronous generator

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A Novel Control Scheme for T-Type Three-Level SSG Converters Using Adaptive PR Controller with a Variable Frequency Resonant PLL

  • Lin, Zhenjun;Huang, Shenghua;Wan, Shanming
    • Journal of Power Electronics
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    • v.16 no.3
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    • pp.1176-1189
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    • 2016
  • In this paper, a novel quasi-direct power control (Q-DPC) scheme based on a resonant frequency adaptive proportional-resonant (PR) current controller with a variable frequency resonant phase locked loop (RPLL) is proposed, which can achieve a fast power response with a unity power factor. It can also adapt to variations of the generator frequency in T-type Three-level shaft synchronous generator (SSG) converters. The PR controller under the static α-β frame is designed to track ac signals and to avert the strong cross coupling under the rotating d-q frame. The fundamental frequency can be precisely acquired by a RPLL from the generator terminal voltage which is distorted by harmonics. Thus, the resonant frequency of the PR controller can be confirmed exactly with optimized performance. Based on an instantaneous power balance, the load power feed-forward is added to the power command to improve the anti-disturbance performance of the dc-link. Simulations based on MATLAB/Simulink and experimental results obtained from a 75kW prototype validate the correctness and effectiveness of the proposed control scheme.

Eliminating the Third Harmonic Effect for Six Phase Permanent Magnet Synchronous Generators in One Phase Open Mode

  • Liu, Jian;Yang, Gui-Jie;Li, Yong;Gao, Hong-Wei;Su, Jian-Yong
    • Journal of Power Electronics
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    • v.14 no.1
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    • pp.92-104
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    • 2014
  • To insure stable operation and eliminate twice torque ripple, a topology for a six phase permanent magnet synchronous generator (SP-PMSG) with a neutral point connected together was analyzed in this paper. By adopting an extended transformation matrix, the mathematic model of the space vector control was established. The voltage and torque equations were deduced while considering the third harmonic flux and inductance. In addition, the suppression third harmonic method and the closed loop control strategy were proposed. A comparison analysis indicates that the cooper loss minimum method and the current magnitude minimum method can meet different application requirements. The voltage compensation amount for each of the methods was deduced which also takes into account the third harmonic effect. A simulation and experimental result comparison validates the consistency through theoretical derivation. It can be seen that all of the two control strategies can meet the requirements of post-fault.

Development of Integrated Start-up and Excitation System for Gas Turbine Synchronous Generator (가스터빈 동기기 통합형 기동 및 여자시스템 개발)

  • Ryu, Hoseon;Cha, Hanju
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.63 no.3
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    • pp.183-188
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    • 2014
  • Power conversion systems used in large gas turbine power plant can be divided into two main part. Because of the initial start-up characteristic of the gas turbine combustor, the gas turbine must be accelerated by starting device(LCI : Load Commutated Inverter) up to 10%~20% of rated speed to ignite it. In addition, the ECS(Excitation Control system) is used to control the rotor field current and reactive power in grid-connected synchronous generator. These two large power conversion systems are located in the same space(container) because of coordination control. Recently, many manufactures develop high speed controller based on function block available in the LCI and ECS with the newest power semiconductor. We also developed high speed controller based on function block to be using these two system and it meets the international standard IEC61131 as using real-time OS(VxWorks) and ISaGRAF. In order to install easily these systems at power plant, main controller, special module and IO module are used with high speed communication line other than electric wire line. Before initial product is installed on the site, prototype is produced and tests are conducted for it. The performance results of Integrated controller and application program(SFC, ECS) were described in this paper. The test results will be considered as the important resources for the application in future.

RTDS based Transient Analysis of PMSG Type wind Power Generation System (RTDS를 이용한 영구자석형 동기발전기를 갖는 풍력발전시스템의 과도현상 해석)

  • Hwang, Chul-Sang;Kim, Gyeong-Hun;Kim, Nam-Won;Lee, Hyo-Guen;Seo, Hyo-Ryong;Park, Jung-Do;Yi, Dong-Young;Lee, Sang-Jin;Park, Min-Won;Yu, In-Keun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.3
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    • pp.572-576
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    • 2011
  • The operation of permanent magnet synchronous generator (PMSG) type wind power generation system (WPGS) can be affected by the utility condition. Consequently, transient condition of utility should be analyzed for the safe and reliable operation of WPGS. This paper presents transient analysis results of a PMSG type WPGS using real time digital simulator (RTDS). A fault condition was applied to the transient analysis of PMSG type WPGS as the transient grid condition. The simulation results were analyzed to show the operational characteristic of PMSG type WPGS under the transient phenomenon of utility.

Modeling and Control of IGBT Converter-Based High-Voltage Direct Current System

  • Kim, Hong-Woo;Ko, Suk-Whan;An, Hae-Joon;Jang, Gil-Soo;Ko, Hee-Sang
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.7
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    • pp.97-104
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    • 2011
  • This paper presents modeling and control for the emerging IGBT converter-based high-voltage direct-current system (IGBT-HVDC). This paper adds to the representation of the IGBT-HVDC system in the dq-synchronous reference frame and its decoupled control scheme. Additionally, since the IGBT-HVDC is able to actively support the grid due to its capacity to control independently active and reactive power production, a reactive power control scheme is presented in order to regulate/contribute to the voltage at a remote location by taking into account its operational state and limits. The ability of the control scheme is assessed and discussed by means of simulations using ahybrid power system, which consists of a permanent magnetic synchronous-generator (PMSG) based wind turbine, an IGBT-HVDC, and a local load.

Development of 10kW Permanent Magnet Synchronous Generator for Small Hydropower Generation (소수력 발전용 10kW급 영구자석형 동기발전기 개발)

  • Jeong, Hak-Gyun;So, Ji-Young;Chung, Dong-Hwa;Ahn, Kang-Soon;Cho, Chong-Hyoun;Kim, Dae-Kyong
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.9
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    • pp.44-52
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    • 2013
  • This paper presents the development of 10 kW permanent magnet synchronous generator (PMSG) for small hydropower plants considering flow rates and net head. The initial and detailed design are determined using a load distribution method (LDM) which is a well-known method for designing an electric machine and a 2D-FEA which is performed for more accurate analysis of PMSG. The characteristic analysis results of proposed model with straight line magnet are satisfied with the initial model with curved magnet. Finally, the analysis and the design results are confirmed by the experimental results.

An Improved Operating Characteristics of Surface Permanent Magnetic Synchronous Generator for 5-Phase 5kW (5상 5kW 표면부착형 영구자석 동기발전기 특성개선)

  • Jung, Hyung-Woo;Kim, Min-Huei;Song, Hyun-Jik;Kim, Dong-Hee
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.27 no.9
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    • pp.53-61
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    • 2013
  • This paper propose a improved operating characteristics of the 5-phase 5kW within developed the surface permanent mount synchronous generator (SPMSG) in order to make a study of a polyphase ac motors keeping hold of more advantages. The developed manufacturing motor was necessary to do improvement of voltage regulation, efficiency, operating characteristics, and so on at the rated load. There are remake a redesigned and distributed stator winding connection without changing the frames of stator and rotor core in previous established generator by a repeat tests. There are shown a amplitude and waveform of the generated electromotive force, FFT analysis of harmonics within output voltages, and reviewing a experiment results in load of resistive and 5-phase induction motor by variable generator output frequency.

A Study on Out-of-Step Relay Operation due to Delayed Fault Clearing in Transmission Line (송전선로 고장제거 지연에 따른 동기 탈조 계전기 동작 검토)

  • Park, Ji-Kyung;Kim, Kwang-Hyun;Kim, Chul-Hwan;Lyu, Young-Sik;Yang, Jeong-Jae
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.10
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    • pp.1466-1473
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    • 2017
  • Generally, electrical torque in synchronous generator is balanced with the rotor mechanical torque under steady-state condition. Thus, the synchronous generator rotor rotates at constant speed. However, under fault condition, the electrical torque output is suddenly decreased and the sum of both torques does not remain constant. If the mechanical torque is not decreased at the same time, the generator rotor would accelerate. Therefore, this accelerating generator rotates at different speeds with respect to other generators in the power system. This phenomena is called as Out-of-Step (OOS). In this paper, we presented a certain two-step type quadrilateral OOS relay setting, which is applicable in actual field, and examined the validity of its setting value with OOS simulation conditions due to delayed fault clearing in transmission line. In order to conduct the study of OOS relay characteristics, we checked the impedance locus and generator output characteristics under the various delayed fault clearing conditions. Moreover, we proposed a countermeasure for avoiding the misoperation of OOS relay during the stable swing by modifying the setting values.

Model Predictive Power Control of a PWM Rectifier for Electromagnetic Transmitters

  • Zhang, Jialin;Zhang, Yiming;Guo, Bing;Gao, Junxia
    • Journal of Power Electronics
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    • v.18 no.3
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    • pp.789-801
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    • 2018
  • Model predictive direct power control (MPDPC) is a widely recognized high-performance control strategy for a three-phase grid-connected pulse width modulation (PWM) rectifier. Unlike those of conventional grid-connected PWM rectifiers, the active and reactive powers of permanent magnet synchronous generator (PMSG)-connected PWM rectifiers, which are used in electromagnetic transmitters, cannot be calculated as the product of voltage and current because the back electromotive force (EMF) of the generator cannot be measured directly. In this study, the predictive power model of the rectifier is obtained by analyzing the relationship among flux, back EMF, active/reactive power, converter voltage, and stator current of the generator. The concept of duty cycle control in the proposed MPDPC is introduced by allocating a fraction of the control period for a nonzero vector and rest time for a zero vector. When nonzero vectors and their duration in the predefined cost function are simultaneously evaluated, the global power ripple minimization is obtained. Simulation and experimental results prove that the proposed MPDPC strategy with duty cycle control for the PMSG-connected PWM rectifier can achieve better control performance than the conventional MPDPC-SVM with grid-connected PWM rectifier.

The Comparison Analysis between Psim Simulation and Motor-Generator (MG) Set Output Characteristics (Psim시뮬레이션과 전동기-발전기(MG) 세트의 출력특성분석)

  • Lim, Hyung-Tack;Jo, Da-Som;Son, Hyo-Soo;Moon, Sang-Soo;Lee, Seok-Hyun;Kim, Kun-Su;Jo, Chul-Hee
    • New & Renewable Energy
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    • v.10 no.3
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    • pp.31-38
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    • 2014
  • The importance of energy is growing according to the energy shortage and environmental concerns. Accordingly, in order to solve the problems about the use of fossil fuel, a renewable energy sources are needed. Global renewable energy power industry's position in the renewable energy market becomes important and new technology development is also essential. MG set composed by the induction motor and permanent magnet synchronous generator for simulating a renewable energy source is based on a suitable experiment equipment. The torque generated by applying a voltage to the induction motor in MG set is used as an input of the permanent magnet synchronous generator. In Psim simulation, the characteristics of the induction motor model was formulated and the output torque characteristics of the motor was controlled using the induction motor side inverter, In this paper, the comparison analysis between Psim simulation and the output characteristics of the MG set is performed in order to identify a renewable energy power system more accurately.