• 한국지능시스템학회논문지
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• 제21권1호
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• pp.55-61
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• 2011

10KW 이하의 소형 풍력 발전 시스템은 언덕이나, 공원, 도시와 같은 협소한 지역에 유연하게 설치될 수 있다는 장점으로 인해 신재생에너지 분야에서 지속적인 연구/개발이 이루어지고 있다. 소형 풍력 발전기는 낮은가격, 고신뢰도 및 고성능이 중요시되기 때문에 최대 전력을 추종하기 위한 다양한 기법이 요구된다. 일반적으로 제어기의 출력은 DC 부하에 전원을 공급하기 때문에 48V 배터리에 연결되어 동작된다. 본 논문에서는 소형 풍력 발전 시스템을 위한 FPGA 기반 MPPT 제어기를 제안하고자하며, 제안된 시스템에서의 다양한 MPPT 알고리즘의 성능을 검증하기 위해 NI 사에서 제작된 Compact-RIO 컨트롤러를 사용하였다.

• 전기학회논문지
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• 제59권9호
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• pp.1560-1565
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• 2010

The renewable resource are getting more attentions with increased concerns on the depletion of fossil fuels and several environmental issues like emission problem. Wind power is a representative option among several renewable sources and the generation capacity using wind power is being increased. However, the wind generation is so volatile on its output characteristic, so it is required to assess the grid impact of wind power generation by measuring the fluctuation effect more precisely. This paper proposes the method for measuring the generation output according to IEC 61400-21(Measurement and assessment of power quality characteristics of grid connected wind turbines) to assess the power quality of wind turbine generation. In addition, it shows an application case to a small-scale wind power generator. In the case study, it suggests a structure design of the proposed measurement instrument both on hardware and software aspects, which is composed of a remote monitoring & data analysis program and an FPGA based real-time signal processing device.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.1080-1088
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• 2014

By combining a wind turbine with an energy storage system (ESS), we are able to attenuate the intermittent wind power characteristic making the power derived from a wind farm dispatchable. This paper evaluates the influence of the phase delay of the low-pass filter in the conventional smoothing power control on the ESS capacity; longer phase delays require a larger ESS capacity. In order to eliminate the effect of the phase delay, we optimize the power dispatch using a zero-phase low-pass filter that results in a non-delayed response in the power dispatch. The proposed power dispatching method significantly minimizes the ESS capacity. In addition, the zero-phase low-pass filter, which is a symmetrical forward-reverse finite impulse response type, is designed simply with a small number of coefficients. Therefore, the proposed dispatching method is not only optimal, but can also be feasibly applied to real wind farms. The efficacy of the proposed dispatching method is verified by integrating a 3 MW wind turbine into the grid using wind data measured on Jeju Island.

• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.81-90
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• 2014

The Jeju-Korea power system is a small-sized network with a system demand ranging from a autumn minimum of 350MW to a summer peak of 716MW. Because Jeju island is well exposed to north-east winds with high speed, applications to connect to Jeju power system are flooded. Considering physical/environmental constraints, Jeju Self-governing Province has also target for the wind power capacity of 1,350MW by 2020. It amounts to two or three times of Jeju average-demand power and wind power limit capacity announced by Korea Power Exchange (KPX) company. Wind farm connection agreements will be signed to maximize utilization of wind resource. In spite of submarine cable HVDC connected to Korea mainland, Jeju power system is independently operated by frequency and reserve control. This study reevaluates wind power limit based on the KPX criteria from 2016 to 2020. First of all wind power generation limit are affected by off-peak demand in Jeju power system. Also the possibility capacity rate of charging wind power output is evaluated by using energy storage system (ESS). As a result, in case of using 110MWh ESS, wind power limit increases 33~55MW(30~50% of ESS), wind power constraint energy decreases from 68,539MWh to 50,301MWh and wind farm capacity factor increases from 25.9 to 26.1% in 2020.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 B
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• pp.1005-1007
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• 2005

Small wind turbines are becoming a viable technology option to supply electricity to landowners. These systems provide energy security, product relatively no environmental harm, and in an appropriate setting can be quite cost-competitive with traditional electricity options. This paper is dealing with the methods how to overcome such inconvenience and with the analysis of characteristic and a field test with a prototype of the stand alone wind turbine was performed. The method applies to small systems, equipped with a coreless axial-flux permanent magnet(AFPM) generator in the turbine, a dc-dc converter and batteries. The analysis concentrates on the effect of the load on the power-wind speed curve of the turbine. The system is designed for direct driven, coupled with turbine and generator with a rated power of, 3kW.

• 조명전기설비학회논문지
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• 제24권6호
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• pp.147-153
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• 2010

소규모 풍력 및 태양광설비가 기존의 배전계통에 연계되어 전압변동, 역률, 주파수, 고조파, 플리커 등의 전원품질 요소에 영향을 줄 것으로 우려하고 있다. 따라서 본 연구에서는 풍력발전설비(AC 링크방식)가 연계된 배전계통의 전력품질에 어떠한 영향을 줄 수 있는지에 대한 조사를 위하여 현재 운영 중에 있는 풍력발전설비의 전력변환장치 앞과 배전선로측 수용가 전원설비 2차측에 각각 전력품질 분석 장치를 설치하여 실측하고 풍력발전기가 가동과 정지 상태에서 배전선로측에 어떠한 영향을 주는지에 대하여 분석하였다. 분석결과 발전기가 가동 및 정지 시 전압변동이 0.34[%] 상승, 전류파형파고율 0.145 정도 상승, 위상차가 가동 중일 때 0.6[$^{\circ}$] 정도의 편차를 발생시켰다.

• 한국유체기계학회 논문집
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• 제20권1호
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• pp.48-52
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• 2017

Small-scale motor-generator sets have been used in laboratories for verification of real large wind turbines whose rated power are more than 1 MW. In this paper, a result of designing a small-scale motor-generator system, which is composed of motor, gear box, flywheel, and generator, is presented in the aspect of speed response. Design objective is to make a small-scale motor-generator system have the same time constant and optimal tip speed ratio region as a real MW wind turbine. A small-scale 3.5 kW motor-generator system for emulating response of a 2 MW wind turbine is considered and designed.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권4호
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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.

• 전기학회논문지
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• 제59권12호
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• pp.2179-2189
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• 2010

This paper deals with analytical techniques for performance evaluation of small scaled wind power generator with outer permanent magnet rotor. In part (1), using transfer relations theorem, magnetic field distribution characteristics by PM and armature reaction field are derived. Moreover, electrical parameters such as back-EMF, inductance and resistance are calculated from the obtained field characteristic equations. The proposed analytical techniques are validated by nonlinear finite element method using commercial software 'Maxwell' and performance experiments of the manufactured generator. In part (2), generating characteristics analysis such as constant speed characteristics and constant resistive load characteristics, and performance evaluation according to variation of wind speed will be accomplished using the derived electrical parameters.

• 전기학회논문지
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• 제63권7호
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• pp.916-923
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• 2014

This paper proposes a low-cost switched-mode rectifier (SMR) for a small-scale wind turbine with a permanent magnet synchronous generator (PMSG) system. Also, a sensorless Fuzzy MPPT control is realized by the proposed system. In the PMSG system with the SMR, the synchronous impedance can be replaced as the input inductor of a boost converter. Moreover, the sensorless MPPT control using the Fuzzy technique is carried out by the duty-ratio regulation of the SMR. The relation between the generating power and the duty-ratio is ruled by the chain rule. The wind turbine model is implemented by the squirrel cage induction motor and generated the variable torque when the generator speed is varied. To verify the performance of the proposed system, simulation and experimental results are executed.