• 제목/요약/키워드: Power Conversion System

검색결과 1,264건 처리시간 0.032초

Study on load tracking characteristics of closed Brayton conversion liquid metal cooled space nuclear power system

  • Li Ge;Huaqi Li;Jianqiang Shan
    • Nuclear Engineering and Technology
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    • 제56권5호
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    • pp.1584-1602
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    • 2024
  • It is vital to output the required electrical power following various task requirements when the space reactor power supply is operating in orbit. The dynamic performance of the closed Brayton cycle thermoelectric conversion system is initially studied and analyzed. Based on this, a load tracking power regulation method is developed for the liquid metal cooled space reactor power system, which takes into account the inlet temperature of the lithium on the hot side of the intermediate heat exchanger, the filling quantity of helium and xenon, and the input amount of the heat pipe radiator module. After comparing several methods, a power regulation method with fast response speed and strong system stability is obtained. Under various changes in power output, the dynamic response characteristics of the ultra-small liquid metal lithium-cooled space reactor concept scheme are analyzed. The transient operation process of 70 % load power shows that core power variation is within 30 % and core coolant temperature can operate at the set safety temperature. The second loop's helium-xenon working fluid has a 65K temperature change range and a 25 % filling quantity. The lithium at the radiator loop outlet changes by less than ±7 K, and the system's main key parameters change as expected, indicating safety. The core system uses less power during 30 % load power transient operation. According to the response characteristics of various system parameters, under low power operation conditions, the lithium working fluid temperature of the radiator circuit and the high-temperature heat pipe operation temperature are limiting conditions for low-power operation, and multiple system parameters must be coordinated to ensure that the radiator system does not condense the lithium working fluid and the heat pipe.

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

  • 류호선;차한주
    • 전기학회논문지P
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    • 제63권3호
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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.

동기기를 사용한 계통연계형 가변속 풍력발전 시스템의 AC-DC-AC 컨버터 구현 및 제어 (Implementation and Control of AC-DC-AC Power Converter in a Grid-Connected Variable Speed Wind Turbine System with Synchronous Generator)

  • 송승호;김성주;함년근
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제54권12호
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    • pp.609-615
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    • 2005
  • A 30kW electrical power conversion system is developed for a variable speed wind turbine. In the wind energy conversion system(WECS) a synchronous generator with field current excitation converts the mechanical energy into electrical energy. As the voltage and the frequency of the generator output vary according to the wind speed, a 6-bridge diode rectifier and a PWM boost chopper is utilized as an ac-dc converter maintaining the constant dc-link voltage with only single switch control. An input current control algorithm for maximum power generation during the variable speed operation is proposed without any usage of speed sensor. Grid connection type PWM inverter converts dc input power to ac output currents into the grid. The active power to the grid is controlled by q-axis current and the reactive power is controlled by d-axis current with appropriate decoupling. The phase angle of utility voltage is detected using software PLL(Phased Locked Loop) in d-q synchronous reference frame. Experimental results from the test of 30kW prototype wind turbine system show that the generator power can be controlled effectively during the variable speed operation without any speed sensor.

동특성해석을 위한 계통연계 풍력발전 시스템의 모델링 (Modeling of a Grid-Connected Wind Energy Conversion System for Dynamic Performance Analysis)

  • 추연식;노경수
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 B
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    • pp.1358-1360
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    • 2002
  • This paper presents a modeling and simulation of a utility-connected wind energy conversion system with a link of a rectifier and an inverter. It discusses the maximum power control algorithm for the wind turbine and presents the relationship of wind turbine output, rotor speed, power coefficient, tip-speed ratio and wind speed when the wind turbine is operated under the maximum power control algorithm. The control objective is to extract maximum power from wind and transfer the power to the utility. This is achieved by controlling the pitch angle of the wind turbine blades. Pitch control method is mechanically complicated, but the control performance is better than that of the stall regulation method. The simulation results performed on MATLAB will show the variation of generator's rotor speed, pitch angle, and generator output.

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DC Microgrid 연계형 PMSG 기반 풍력에너지 변환 시스템의 전력 품질 개선을 위한 가변 샘플링 시간이 적용된 모델예측제어 (Model Predictive Control with Variable Sampling Time for Improving Power Quality of PMSG-based Wind Energy Conversion System in DC Microgrid)

  • 이재형;추경민;정원상;원충연
    • 전력전자학회:학술대회논문집
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    • 전력전자학회 2019년도 추계학술대회
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    • pp.180-181
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    • 2019
  • This paper proposes a method for improving the power quality of PMSG-based wind energy conversion system based on model predictive control in DC Microgrid. The MPC has a fast dynamic response. However, a large torque ripple deteriorating power quality is generated by a large and fixed switching period. On the other hand, the proposed method improves the power quality by setting the sampling time having zero torque error. The validity of the proposed method is verified through PSIM simulation.

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Maximum Power Point Tracking Control Scheme for Grid Connected Variable Speed Wind Driven Self-Excited Induction Generator

  • El-Sousy Fayez F. M.;Orabi Mohamed;Godah Hatem
    • Journal of Power Electronics
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    • 제6권1호
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    • pp.52-66
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    • 2006
  • This paper proposes a wind energy conversion system connected to a grid using a self-excited induction generator (SEIG) based on the maximum power point tracking (MPPT) control scheme. The induction generator (IG) is controlled by the MPPT below the base speed and the maximum energy can be captured from the wind turbine. Therefore, the stator currents of the IG are optimally controlled using the indirect field orientation control (IFOC) according to the generator speed in order to maximize the generated power from the wind turbine. The SEIG feeds a (CRPWM) converter which regulates the DC-link voltage at a constant value where the speed of the IG is varied. Based on the IG d-q axes dynamic model in the synchronous reference frame at field orientation, high-performance synchronous current controllers with satisfactory performance are designed and analyzed. Utilizing these current controllers and IFOC, a fast dynamic response and low current harmonic distortion are attained. The regulated DC-link voltage feeds a grid connected CRPWM inverter. By using the virtual flux orientation control and the synchronous frame current regulators for the grid connected CRPWM inverter, a fast current response, low harmonic distortion and unity power factor are achieved. The complete system has been simulated with different wind velocities. The simulation results are presented to illustrate the effectiveness of the proposed MPPT control scheme for a wind energy system. In the simulation results, the d-q axes current controllers and DC-link voltage controller give prominent dynamic response in command tracking and load regulation characteristics.

소형 스털링 엔진을 이용한 태양열 발전 시스템 (Solar Power Generation System Using A Small-Sized Stirling Engine)

  • 김기범
    • 한국산학기술학회논문지
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    • 제13권8호
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    • pp.3339-3344
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    • 2012
  • 태양 에너지 변환 효율이 높은 접시형 집광기와 스털링 엔진을 이용한 발전 방식을 조사하기 위하여 본 연구에서는 소형 스털링 엔진을 이용하여 좁은 공간에서 발전용으로 사용할 수 있는 시스템을 개발하였고, 기초 실험을 수행하였다. 본 연구에서 제작한 발전 시스템을 위하여 50만원의 제작비가 소요되었고, 제작한 시스템으로 최대 0.56 kWh의 전기를 발전하였으며, 에너지 변환 효율은 약 10%로 측정되었다. 시스템의 최적 설계를 통하여 더 높은 출력을 얻을 수 있으며, 본 연구의 기초 실험 데이터는 많은 태양열 발전 관련 분야에서 유용하게 사용될 것으로 사료된다.

6.6 kW On-Vehicle Charger with a Hybrid Si IGBTs and SiC SBDs Based Booster Power Module

  • Han, Timothy Junghee;Preston, Jared;Ouwerkerk, David
    • Journal of Power Electronics
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    • 제13권4호
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    • pp.584-591
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    • 2013
  • In this paper, a hybrid booster power module with Si IGBT and Silicon Carbide (SiC) Schottky Barrier Diode (SBDs) is presented. The switching characteristics of the hybrid booster module are compared with commercial Silicon IGBT/Si PIN diode based modules. We applied the booster power module into a non-isolated on board vehicle charger with a simple buck-booster topology. The performances of the on-vehicle charger are analyzed and measured with different power modules. The test data is measured in the same system, at the same points of operation, using the conventional Si and hybrid Si/SiC power modules. The measured power conversion efficiency of the proposed on-vehicle charger is 96.4 % with the SiC SBD based hybrid booster module. The conversion efficiency gain of 1.4 % is realizable by replacing the Si-based booster module with the Si IGBT/SiC SBD hybrid boost module in the 6.6 kW on-vehicle chargers.

Status Review of Power Electronic Converters for Fuel Cell Applications

  • Emadi, Ali;Williamson, Sheldon S.
    • Journal of Power Electronics
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    • 제1권2호
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    • pp.133-144
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    • 2001
  • Power electronics plays an important role in providing an interface between fuel cells and loads. Furthermore, power electronic converters ensure that the power is reliably and efficiently delivered to the load in the required DC or AC form. In this paper, major types of fuel cells are presented. Basic structures, operating principles, and different applications of fuel cells are described. In addition, current status and future trends in the areas of power electronics for fuel cells are described. In addition, current statue and future trends in the areas of power electronics for fuel cell applications are explained. A review of fuel cell power electronic system topologies and basic requirements are given as well.

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Design and Control of an Optimized Battery Charger for an xEV Based on Photovoltaic Power Systems

  • Kim, Dong-Hee;Cheo, Gyu-Yeong;Lee, Byoung-Kuk
    • Journal of Electrical Engineering and Technology
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    • 제9권5호
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    • pp.1602-1613
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    • 2014
  • The continuous growth of electric vehicles has caused electric power shortages in conventional utilities owing to the charging of electric-vehicle batteries. In order to increase the capacity of these utilities, photovoltaic systems may be an appropriate solution because of their benefits. However, a large amount of loss is generated in a conventional charging structure using photovoltaic sources owing to the many power conversion processes. This paper describes a simple integrated battery charger that utilizes a PV generation system. Moreover, the system control algorithm is deduced by analyzing the operation modes in order to control the proposed integrated system. The proposed system and algorithm are verified by a 3.3-kW prototype, resulting in an increase in the efficiency of approximately 7% to 15% compared with the conventional system. And, to examine the feasibility of the proposed system, the simulation for multi-charger with various conditions are progressed.