• 한국산학기술학회논문지
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• 제14권6호
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• pp.2979-2984
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• 2013

본 논문은 도서지역에서 운용되고 있는 풍력-디젤 하이브리드 발전시스템의 풍속변화 등으로 인한 주파수변동 문제를 해결할 수 있는 플라이휘일 저장장치의 모델링 및 제어기 설계 방법을 제안하였다. 플라이휘일 저장장치는 효율측면에서 유리한 영구자석 동기기형 플라이휘일로 선정하여 모델링하였고, 주파수보상 제어기는 AC/DC/AC 양방향컨버터로 구성하되 동기기측 컨버터는 연계계통의 주파수변동에 대하여 충방전운전을 하도록 하고, 계통측 컨버터는 직류버스전압 일정제어를 통하여 출력을 하도록 설계하였다. 제안된 모델링 및 제어기 설계방법을 풍력-디젤 하이브리드 독립운전계통에 적용한 결과 풍속변화에 따른 주파수변동을 적정범위내로 유지할 수 있었다.

• Journal of Magnetics
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• 제20권2호
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• pp.176-185
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• 2015

We present the design optimization of the magnetic pole and slot design options that minimize the cogging torque of permanent-magnet (PM) brushless generators for small wind turbine generators. Most small wind-turbines use direct-driven PM generators which have the characteristics of low speed and high efficiency. Small wind-turbines are usually self-starting and require very simple controls. The cogging torque is an inherent characteristic of PM generators, and is mainly caused by the generator's geometry. The inherent the cogging torque can cause problems during turbine start-up and cut-in in order to start softly and to run a power generator even when there is little wind power during turbine start-up. Thus, to improve the operation of small turbines, it is important to minimize the cogging torque. To determine the effects of the cogging torque reductions, we adjust the slot opening width, slot skewing, mounting method of magnets, magnet shape, and the opening and combinations of different numbers of slots per pole. Of these different methods, we combine the methods and optimized the design variables for the most significant design options affecting the cogging torque. Finally, we apply to the target design model and compare FEA simulation and measured results to validate the design optimization.

• 조명전기설비학회논문지
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• 제28권6호
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• pp.106-112
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• 2014

Recently, tidal power generation has gained much attention. South Korea's tidal power generation systems were imported from abroad by turnkey type and have being operated. Therefore, for efficient operation and technological independence of a tidal power system, development of core technology is required. This paper deals with the start stop control system of water turbine generator in the tidal power plant, as one of our development project results. Using the SCADA system, the status and operations of water turbine generator in the tidal power plant, as well as simulation for calculation of maximum power were carried out. A small model type of start stop control device was also developed. In addition, the control system in Sihwa tidal power plant was modeled, and the results obtained by the dynamic simulation were given in graphics by 2D simulator.

• 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.

• Journal of Power Electronics
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• 제18권1호
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• pp.195-203
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• 2018

In the variable speed Wind Turbine based on ElectroMagnetic Coupler (WT-EMC), a synchronous generator is coupled directly to the grid. Therefore, like conventional power plants, WT-EMC is able to inherently support grid frequency. However, due to the reduced inertia of the synchronous generator, WT-EMC is expected to be controlled to increase its output power in response to a grid frequency drop to support grid frequency. Similar to the grid frequency support control of Type 3 or Type 4 wind turbine, inertial control and droop control can be used to calculate the WT-EMC additional output power reference according to the synchronous generator speed. In this paper, an experimental platform is built to study the grid frequency support from WT-EMC with inertial control and droop control. Two synchronous generators, driven by two induction motors controlled by two converters, are used to emulate the synchronous generators in conventional power plants and in WT-EMCs respectively. The effectiveness of the grid frequency support from WT-EMC with inertial control and droop control responding to a grid frequency drop is validated by experimental results. The selection of the grid frequency support controller and its gain for WT-EMC is analyzed briefly.

• 한국정보기술학회논문지
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• 제15권12호
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• pp.181-188
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• 2017

레저 활동 인구의 증가와 다양화로 이동용 전력 시스템에 대한 수요가 많고 친환경적인 전력 발전 시스템에 대한 요구가 늘어나고 있으며 이를 충족 시킬만한 발전 장비로 소형 풍력 발전시스템이 대안으로 떠오르고 있다. 이동용 소형 풍력발전기를 개발할 때 가장 중요한 사항으로는 발전기의 무게를 줄이고 효율을 증가시키는 것이다. 기존의 300W급 풍력 발전기의 무게는 10kg정도로 이를 4kg이하로 줄여서 휴대가 용이하게 하면서 고 효율의 풍력 발전기용 발전기를 설계 제작하였다. 또한, 돌풍이 발생하는 한국의 풍량과 지형의 특성상 미풍에서도 발전이 가능하고 도심 및 농어촌 등에서도 독립적으로 사용할 수 있는 소형 풍력발전기를 설계 제작하였다. 기초설계 및 최적화설계를 통해 가볍고 효율이 높은 발전기를 제작하였다. 본 논문에서는 중량을 줄인 300W급 풍력발전기를 설계하고 시제품으로 제작 하였다. 제작한 300W 풍력발전기는 무부하 시험 시 정격속도 900rpm에서 평균출력전압이 24.7V이었으며, 제작된 발전기의 부하시험시 평균 선간전압 : 36.8V, 평균 상전류 : 2.62A로 기계적 입력이 339.84W일 때 출력전력은 289.5W로 측정되었고 이때의 효율은 85.18%이었다. 제작된 발전기 무게는 3.84kg이었다.

• 플랜트 저널
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• 제17권4호
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• pp.35-40
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• 2021

본 연구에서는 서인천복합 6호기 가스터빈 발전기계통에 대하여 기술특성시험을 실시하여 모델정수를 도출하고 검증하였다. 발전기 최대/최소 무효전력 한계시험 결과 최대 무효전력 한계는 80 MVar이고, 최소 무효전력 한계는 -30 MVar이다. 발전기는 GENROU 모델을 사용하였고, 계자시정수(T'do)는 4.077 s, 관성정수(H)는 5.461 P.U로 결정하였다. 여자시스템은 ESST4B 모델을 사용, 무부하 2% AVR 스텝시험을 모의하는 방식으로 모델정수를 도출하고 검증하였으며, PSS 모델링은 PSS2A 모델정수로 도출하였고, PSS Off/On일때 측정된 계측 데이터를 모의, 비교하여 검증하였다. 조속기-터빈는 GGOV1 모델을 사용하여 모델정수를 도출하고 검증하였다. PSS/E 시뮬레이션 프로그램을 통해 10% 조속기 스텝시험을 모의하여 결정된 조속기-터빈 모델정수의 수치 안정성을 확인하였다.

• 제어로봇시스템학회논문지
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• 제10권3호
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• pp.286-293
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• 2004

This paper presents the result of a study on the starter control for a turbo generator. Because a starter in gear box type turbo-generator system is composed of gearbox and brush DC motor, it should be replaced with High Speed Generator(HSG)) in HSG type Turbo-generator. There-ore, it is necessary to design a new starting algorithm and starter. In gearbox type system, brush DC motor is rotated to the designed speed using low voltage-high current battery power. After brush DC motor speed is increased to several times by gearbox, gas turbine engine can be rotated to designed starting speed. If we implement a starter with High Speed Generator(HSG), it is necessary to drive high-speed generator to high-speed motor. High-speed generator with permanent magnet on rotor has a low leakage inductance fur driving high-speed rotation, and it is necessary high DC link voltage for inverter when High-speed generator is driven to high speed. This paper presents result of development of the boost converter for converting high voltage DC from low battery voltage and design of the inverter for controlling a high frequency current to be injected to motor winding. Also, we show performance of the designed starter by driving the turbo generator.

• 한국산업융합학회 논문집
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• 제24권6_2호
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• pp.801-808
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• 2021

In this paper, a numerical analysis was conducted on the effect of the flow control valve of a oscillation water column(OWC) type wave power generator turbine. The OWC wave power turbine operates with compressed air in the air chamber according to the change of wave height. When the wave height changes rapidly, a flow control valve is required due to overload of the turbine and reduced efficiency. Therefore, in this paper, a flow control valve with an opening angle of 60 degrees was installed in the front of the turbine, and the pressure drop, torque, and overall performance were calculated according to the change of turbine RPM and flow rate of turbine inlet. In conclusion, the flow control valve with an opening angle of 60 degrees affects when the turbine rotates at low rotation and the inlet flow rate is large. But it does not have a significant effect on overall turbine performance and it is necessary to find the optimal angle in the future works.

• Nuclear Engineering and Technology
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• 제39권2호
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• pp.103-110
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• 2007

The High Temperature Gas-cooled Reactor (HTGR) possesses inherent safety features and is recognized as a representative advanced nuclear system for the future. Based on the success of the HTR-10, the long-time operation test and safety demonstration tests were carried out. The long-time operation test verifies that the operation procedure and control method are appropriate for the HTR-10 and the safety demonstration test shows that the HTR-10 possesses inherent safety features with a great margin. Meanwhile, two new projects have been recently launched to further develop HTGR technology. One is a prototype modular plant, denoted as HTR-PM, to demonstrate the commercial capability of the HTGR power plant. The HTR-PM is designed as $2{\times}250$ MWt, pebble bed core with a steam turbine generator that serves as an energy conversion system. The other is a gas turbine generator system coupled with the HTR-10, denoted as HTR-10GT, built to demonstrate the feasibility of the HTGR gas turbine technology. The gas turbine generator system is designed in a single shaft configuration supported by active magnetic bearings (AMB). The HTR-10GT project is now in the stage of engineering design and component fabrication. R&D on the helium turbocompressor, a key component, and the key technology of AMB are in progress.