• Journal of Institute of Control, Robotics and Systems
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• v.15 no.12
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• pp.1163-1168
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• 2009

The power quality of wind energy becomes more and more important in connecting wind-farms to the grid, especially weak grid. This paper presents the simulation of a wind farm of a permanent magnet synchronous generator (PMSG) and a doubly fed induction generator (DFIG). Flicker mitigation is performed by using PMSG as a static synchronous compensator (STATCOM) to regulate the voltage at the point of common coupling (PCC). A benefit of the measure is that integrating two function of to control the active power flow and to reduce the voltage flicker in a wind farm. Simulation results show that controlling PMSG is an effective and economic measure in reducing the flicker during continuous operation of grid connected wind turbines regardless of short circuit capacity ratio, turbulence intensity and grid impedance angle.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1556-1570
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• 2016

In the process of virtual inertia control (VIC), the frequency regulation capability of the directly-driven wind turbine with permanent-magnet synchronous generator (D-PMSG) on wind farm is related to its rotor kinetic energy and capacity margin. This paper proposes the method for assessing the D-PMSG frequency regulation capability and defining its coefficient according to the operating state of wind power generators. In addition, the calculating method of parameters in VIC is also discussed according to the principles of primary frequency regulation and inertia response of synchronous generators. Then, by introducing the capability coefficient into the proportion-differential virtual inertia control (PD-VIC) for power coordination, a coordinated virtual inertia control (C-VIC) strategy is developed, with the consideration of the difference in frequency regulation capability between wind power generators. The proposed control method can not only give full play to the frequency regulation capability of wind power generators, decrease the movements of the pitch angle control system but also bring some self-coordination capability to different wind power generators thus to avoid a secondary drop in system frequency. The simulations and experiments prove the proposed method to be effective and practicable.

• The Transactions of the Korean Institute of Power Electronics
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• v.19 no.6
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• pp.549-556
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• 2014

This study proposes a parallel operation strategy for small wind turbine systems. A small wind turbine system consists of blade, permanent magnet synchronous generator, three-phase diode rectifier, DC/DC buck converter, and the battery load. This configuration has reliability, simple control algorithm, high efficiency, and low cost. In spite of these advantages, the system stops when unexpected failures occur. Possible failures can be divided into mechanical and electrical parts. The proposed strategy focuses on the failure of electrical parts, which is verified by numerical analysis through equivalent circuit and acquired general formula of small wind power generation systems. Simulation and experimental results prove its efficiency and usefulness.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.510-511
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• 2011

This paper has represented about the activated scheme the Honam regional wind power industry favorable products. The favorable products are the MW offshore wind system with Outer-rotor type PMSG-6 products, the 3MW offshore wind system with adatation type of west-south sea, and the hybrid generator system with wind turbine technology basis-2 products.

• Journal of international Conference on Electrical Machines and Systems
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• v.1 no.2
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• pp.116-124
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• 2012

Wind is an abundant source of natural energy which can be utilized to generate power. Wind velocity does not remain constant, and as a result the output power of wind turbine generators (WTGs) fluctuates. To reduce the fluctuation, different approaches are already being proposed, such as energy storage devices, electric double layer capacitors, flywheels, and so on. These methods are effective but require a significant extra cost to installation and maintenance. This paper proposes to reduce output power fluctuation by controlling kinetic energy of a WTG system. A MW-class pitch-regulated permanent magnet synchronous generator (PMSG) is introduced to apply a power fluctuation reducing method. The major advantage of this proposed method is that, an additional energy storage system is not required to control the power fluctuation. Additionally, the proposed method can mitigate shaft stress of a WTG system. Which is reflected in an enhanced reliability of the wind turbine. Moreover, the proposed method can be changed to the maximum power point tracking (MPPT) control method by adjusting an averaging time. The proposed power smoothing control is compared with the MPPT control method and verified by using the MATLAB SIMULINK environment.

• The Transactions of the Korean Institute of Power Electronics
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• v.20 no.5
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• pp.410-420
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• 2015

This paper provides a comparison of power converter loss and thermal description for voltage source and current source type 5 MW-class medium-voltage topologies of wind turbines. Neutral-point clamped three-level converter is adopted for a voltage source type topology, whereas a two-level converter is employed for current source type topology, considering the popularity in the industry. To match the required voltage level of 4160 V with the same switching device of IGCT as in the voltage source converter, two active switches are connected in series for the case of current source converter. Transient thermal modeling of a four-layer Foster network for heat transfer is done to better estimate the transient junction and case temperature of power semiconductors during various operating conditions in wind turbines. The loss analysis is confirmed through PLECS simulations. Comparison result shows that the VSC-based wind turbine system has higher efficiency than the CSC under the rated operating conditions.

• Proceedings of the KIPE Conference
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• 2009.11a
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• pp.135-138
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• 2009

In this paper, a novel maximum power point tracking (MPPT) for a PMSG-based variable speed wind power system is proposed using the fuzzy logic algorithm. The control algorithm is developed based on the normal hill climb searching (HCS) method, commonly used in wind energy conversion systems (WECS). The inputs of fuzzy-based controller are the derivations of DC output power and the step size of DC/DC converter duty cycles. The main advantages of the proposed MPPT method are no need to measure the wind velocity and the generator rotational speed. As such, the control algorithm is independent of turbine characteristics, achieving the fast dynamic responses with non-linear fuzzy systems. The effectiveness of the proposed MPPT strategy has been verified through the simulated results.

• Journal of IKEEE
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• v.21 no.1
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• pp.81-84
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• 2017

As the demands for offshore wind power generation systems on a large scale have grown dramatically, and extensive developments in PMSG (Permanent Magnet Synchronous Generator) and DFIG (Doubly-fed Induction Generator) wind turbine system have been going on. However, the wind power systems have been more sophisticated, and their reliability becomes critical issues. Averagely, wind turbines have shut down for about a week per year for repairs and maintenance. Especially the high speed gearbox of DFIG is inevitable components for high power generation, but becomes one of the critical failures. In this paper, a new reliable gearless wind turbine structure is proposed. The gearless wind turbine can operate on a maximum power points by controlling the speed of a rotational stator. The proposed approach is verified by PSIM simulations, resulting in increased energy reliability.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.509-510
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• 2015

본 논문에서는 강인한 계통과 연계되어 있지 않은 독립형 마이크로그리드에 PMSG (Permanent Magnet Synchronous Generator)기반 풍력발전기를 연계하였을 때의 계통 특성을 분석한다. 독립형 마이크로그리드에서는 계통과 연계되어 있지 않기 때문에 하나의 분산전원이 기준전원으로 동작하여 전압과 주파수를 유지하고 나머지 분산전원이 전력흐름에 따라 전류제어를 수행하여야 한다. 인버터 기반의 전원을 기준전원으로 설정하고 PMSG 기반 풍력발전기를 연계하였을 시 컨버터의 전압 제어 및 정격출력보다 큰 출력이 나올 경우 피치각 제어를 통한 출력 특성과 제어기의 성능을 검증한다.

• Journal of the Korean Solar Energy Society
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• v.34 no.2
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• pp.8-15
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• 2014

The objective of this paper is to suggest a design topology of permanent magnet synchronous generator with 2,000kW capacities for wind turbine. The suggested topology is to provide 3 split magnet PMSG instead of single magnet, and performed an analysis of eddy current loss and iron loss for suggested type using ansoft maxwell commercial program. The simulation results of suggested magnet type show there duction of eddy current loss as 13.87kW with loadless conditions and23.48kW with rated conditions, but iron loss for rotor yoke show the in creasing trend as2.2kW with loadless conditions and 0.2kW with rated conditions. The suggested 3 split maget type is to identified as more useful for 2,000kW PMSG.