• Title/Summary/Keyword: AC modeling

검색결과 243건 처리시간 0.021초

AC/DC 하이브리드형 혼합송전계통에서 DC 케이블의 유도전압평가에 의한 적정배열 선정 (Proper Cable Arrangement Selection by Induced Voltage Evaluation of DC Cable in AC/DC Hybrid Combined Transmission Systems)

  • 손용대;이종범
    • 전기학회논문지
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    • 제64권5호
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    • pp.680-688
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    • 2015
  • Hybrid type combined transmission systems is being operated by AC and DC line at the same space will be expanded instead of the overhead line. However, such hybrid type combined system has problem like the arrangement selection of DC cable for effective system operation. In this paper, to select the proper arrangement of DC cable, induced voltage of DC cable influenced by AC cable was analyzed in case of several type arrangement of DC cable. Such induced voltage is in detailed analyzed not only in case of steady, but transient state. The arrangement which has the lowest induced voltage is selected as the proper one. EMTP/ATPDraw is used for modeling and analysis of hybrid type combined transmission system.

AC-DC Zeta Converter for Power Quality Improvement in Direct Torque Controlled PMSM Drive

  • Singh Bhim;Singh B.P.;Dwivedi Sanjeet
    • Journal of Power Electronics
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    • 제6권2호
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    • pp.146-162
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    • 2006
  • This paper deals with the analysis, design and implementation of an AC-DC Zeta converter in discontinuous current mode (DCM) of operation used for power quality improvement at AC mains in direct torque controlled (DTC) permanent magnet synchronous motor (PMSM) drives. The designed Zeta converter feeds a direct torque controlled PMSM drive system. Modeling and simulation is carried out in a standard PSIM software environment. Test results are obtained on the developed prototype Zeta converter using DSP ADMC401. The results obtained demonstrate the effectiveness of the Zeta converter in improving power quality at AC mains in the PMSM drive system.

A Novel High-Performance Strategy for A Sensorless AC Motor Drive

  • Lee, Dong-Hee;Kwon, Young-Ahn
    • KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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    • 제2B권3호
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    • pp.81-89
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    • 2002
  • The sensorless AC motor drive is a popular topic of study due to the cost and reliability of speed and position sensors. Most sensorless algorithms are based on the mathematical modeling of motors including electrical variables such as phase current and voltage. Therefore, the accuracy of such variables largely affects the performance of the sensorless AC motor drive. However, the output voltage of the SVPWM-VSI, which is widely used in sensorless AC motor drives, has considerable errors. In particular, the SVPWM-VSI is error-prone in the low speed range because the constant DC link voltage causes poor resolution in a low output voltage command and the output voltage is distorted due to dead time and voltage drop. This paper investigates a novel high-performance strategy for overcoming these problems in a sensorless ac motor drive. In this paper, a variation of the DC link voltage and a direct compensation for dead time and voltage drop are proposed. The variable DC link voltage leads to an improved resolution of the inverter output voltage, especially in the motor's low speed range. The direct compensation for dead time and voltage drop directly calculates the duration of the switching voltage vector without the modification of the reference voltage and needs no additional circuits. In addition, the proposed strategy reduces a current ripple, which deteriorates the accuracy of a monitored current and causes torque ripple and additional loss. Simulation and experimentation have been performed to verify the proposed strategy.

Supervisory Control for Energy Management of Islanded Hybrid AC/DC Microgrid

  • Mansour, Henda Ben;Chaarabi, Lotfi;Jelassi, Khaled;Guerrero, Josep M.
    • International Journal of Computer Science & Network Security
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    • 제22권3호
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    • pp.355-363
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    • 2022
  • This paper presents the modeling for islanded hybrid AC/DC microgrid and the verification of the proposed supervisory controller for energy management for this microgrid. The supervisory controller allows the microgrid system to operate in different power flows through the proposed control algorithm, it has several roles in the management of the energy flow between the different components of the microgrid for reliable operation. The proposed microgrid has both essential objectives such as the maximum use of renewable energies resources and the reduction of multiple conversion processes in an individual AC or DC microgrids. The microgrid system considered for this study has a solar photovoltaic (PV), a wind turbine (WT), a battery (BT), and a AC/DC loads. A small islanded hybrid AC/DC microgrid has been modeled and simulated using the MATLAB-Simulink. The simulation results show that the system can maintain stable operation under the proposed supervisory controller when the microgrid is switched from one operating mode of energy flow to another.

345kV 계통 모델링 데이터를 활용한 과여자 보호계전기법 (Over-Excitation Protection Relaying using the 345kV Power System Modeling Data)

  • 박철원;반우현
    • 전기학회논문지P
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    • 제60권4호
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    • pp.175-180
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    • 2011
  • A large AC generator is an important component of the power system. It is a need for research of AC generator protection relay for the next-generation ECMS and an efficient operation of protection control system. However, most of protection and control systems used in power plants have been still imported as turn-key and operated in domestic. This may cause the lack of the correct understanding on the protection systems and methods, and thus have difficulties in optimal operation. In this paper, over-excitation protection relaying is one of the protective factors in generator protection IED was presented. The cause and protection principles were dealt and, DFT-based gain compensation algorithm was adopted for the frequency measurement. The Republic of Korea 345kV modeling data by EMTP-RV was used for performance evaluation.

Analysis, Design, Modeling, Simulation and Development of Single-Switch AC-DC Converters for Power Factor and Efficiency Improvement

  • Singh, Bhim;Chaturvedi, Ganesh Dutt
    • Journal of Power Electronics
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    • 제8권1호
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    • pp.51-59
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    • 2008
  • This paper addresses several issues concerning the analysis, design, modeling, simulation and development of single-phase, single-switch, power factor corrected AC-DC high frequency switching converter topologies with transformer isolation. A detailed analysis and design is presented for single-switch topologies, namely forward buck, flyback, Cuk, Sepic and Zeta buck-boost converters, with high frequency isolation for discontinuous conduction modes (DCM) of operation. With an awareness of modem design trends towards improved performance, these switching converters are designed for low power rating and low output voltage, typically 20.25W with 13.5V in DCM operation. Laboratory prototypes of the proposed single-switch converters in DCM operation are developed and test results are presented to validate the proposed design and developed model of the system.

전기철도 3상유도전동기의 기동특성을 고려한 STATCOM에 의한 전압강하 보상에 관한연구 (A Study on Voltage Drop Compensation by STATCOM Considering Dynamic Characteristics of the 3-Phase Induction Motor in Electric Railway Systems)

  • 황승호;오민혁;이병하
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 추계학술대회 논문집 전력기술부문
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    • pp.337-339
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    • 2005
  • The purpose of this paper is to compensate the voltage drop of the power system in the AC High-Speed Railway (HSR). Reactive power compensation is often the most effective way to improve system voltage drop. The suitable modeling of the electric railway system should be applied to the EMTP. the dynamic characteristics of 3-Phase Induction Motor in Electric Railway Systems is considered for precise modeling. it is shown through EMTP simulation that voltage drop can be compensated effectively by STATCOM.

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EMTP MODELS를 이용한 전기철도 FACTS 설비의 제어 구현 연구 (A Study on control realization of FACTS equipment in Electric Railway Systems using EMTP MODELS)

  • 오민혁;이병하
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 A
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    • pp.329-330
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    • 2006
  • The purpose of this paper is to compensate the voltage drop of the power system in the AC Electric Railway Systems. Reactive power compensation is often the most effective way to improve system voltage drop. The suitable modeling of the electric railway system should be applied to the EMTP. the dynamic characteristics of 3-Phase Induction Motor in Electric Railway Systems is considered for precise modeling. it is shown through EMTP simulation using EMTP MODELS that voltage drop can be compensated effectively by STATCOM.

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Modeling and Control of Three-Phase Self-Excited Induction Generator Connected to Grid

  • Chandrasekaran, Natarajan;Karthikeyan, A
    • Transactions on Electrical and Electronic Materials
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    • 제18권5호
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    • pp.265-272
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    • 2017
  • This paper presents the dynamic modeling, analysis, and control of an AC/DC/AC-assisted, self-excited induction generator connected to the grid. The dynamic model includes wind turbine models with pitch control, gear boxes, self-excited induction generators, excitation capacitance, inductive load models, controlled six-pulse rectifiers, and novel state-space models of a grid-connected inverter. The system has been simulated to verify its capabilities of buildup voltage, stator flux response, stator phase current, electromagnetic torque, and magnetizing inductance variation during both the dynamic and steady states with a variable-speed prime mover. The complete setup of the above dynamic models was simulated using MATLAB/SIMULINK.

정전기력 가진에 의한 외팔보형 탄소나노튜브 공진기의 비선형 동적 응답 (Nonlinear Dynamic Response of Cantilevered Carbon Nanotube Resonator by Electrostatic Excitation)

  • 김일광;이수일
    • 한국소음진동공학회:학술대회논문집
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    • 한국소음진동공학회 2011년도 춘계학술대회 논문집
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    • pp.447-452
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    • 2011
  • This paper predicted the dynamic behaviors of a cantilevered carbon nanotube(CNT) incorporating the electrostatic force, van der Waals interactions between the CNT and ground plane. The structural model of the CNT includes geometric and inertial nonlinearities for predicting various phenomena of nonlinear responses of the CNT due to the electrostatic force. In order to solve the problem, we used Galerkin's approximation and the numerical integration techniques and as a result, we predicted characteristics of nonlinear response of nano resonator. The cantilevered CNT shows complex dynamic responses and instabilities due to the applied ac and ac voltages, and driving frequencies. The results investigated in this paper are helpful to the modeling of nanotube based electromechanical devices such as nano-resonators and nano-sensors.

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