• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.65 no.4
• /
• pp.533-538
• /
• 2016

In a power grid that has a high penetration of wind power, the highly-fluctuating output power of wind turbine generators (WTGs) adversely impacts the power quality in terms of the system frequency. This paper proposes a power smoothing scheme of a variable-speed WTG that can smooth its fluctuating output power caused by varying wind speeds, thereby improving system frequency regulation. To achieve this, an additional loop relying on the frequency deviation that operates in association with the maximum power point tracking control loop, is proposed; its control gain is modified with the rotor speed. For a low rotor speed, to ensure the stable operation of a WTG, the gain is set to be proportional to the square of the rotor speed. For a high rotor speed, to improve the power smoothing capability, the control gain is set to be proportional to the cube of the rotor speed. The performance of the proposed scheme is investigated under varying wind speeds for the IEEE 14-bus system using an EMTP-RV simulator. The simulation results indicate that the proposed scheme can mitigate the output power fluctuation of WTGs caused by varying wind speeds by adjusting the control gain depending on the rotor speed, thereby supporting system frequency regulation.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.846-848
• /
• 2000

In the early development of wind energy, the majority of wind turbines were operated at constant speed. Recently, the number of variable-speed wind turbines adopted pitch control apparatus has increased. This paper deal with a simulation of pitch control of variable-speed wind turbine and the response of pitch angle is traced in a given random wind speed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.3 no.3
• /
• pp.40-46
• /
• 1999

Aerodynamic performance and starting characteristic of wind turbine blade are important factors that determine the whole system as rated power, operating method, etc. Therefore, starting characteristic according to aerodynamic performance, wind speed and blade pitch angle should be examined while wind turbine blade is designed. In this study, the aerodynamic analysis program of 750㎾ class horizontal axis wind turbine blade was developed and to certify this program, the aerodynamic performance of the commercialized blade was analyzed with it. The analysis result was corresponding to the value presented from manufacturer. And the starting analysis program was developed on the basis of the developed aerodynamic analysis program and starting analysis was performed. As a result, it was confirmed that variable speed operation and variable pitch control are profitable to wind turbine used in low wind speed as our country.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.8
• /
• pp.150-157
• /
• 2005

This paper presents the simulation modeling and analysis of variable wind speed turbine system(VWTS) using the doubly fed induction generator(DFIG) connected the back to back converter system in the rotor side. In the simulation, using the model system which has the 660[kW] rated power, blade control and the dual converter system are modeled for verifying the control characteristics. The VWTS is controlled by the optimal pitch angle for maximum output power under the rated wind speed, and for the rated output power over the rated wind speed. And also power factor is controlled by the reactive power. To verify the effectiveness of the proposed method, simulation results are compared with the actual data from the V47 VWTS located in Hangwon wind farm in Jeju-Do. According to the comparison of these results, this method shows excellent performance.

• Journal of Energy Engineering
• /
• v.12 no.4
• /
• pp.309-319
• /
• 2003

The main purpose of this paper is to present a simulation model for assessing the impacts of a variable speed wind turbine (VSWT) on the distribution network and perform a simulation analysis of volt-age profiles and harmonics along the wind turbine installed feeder using the presented model. The modeled wind energy conversion system consists of a fixed pitch wind turbine and a permanent-magnet synchronous generator, in which a controllable power electronics inverter performs variable speed operation and reactive power output control. Impact analysis on voltage profiles and harmonics of a VSWT-installed distribution feeder is addressed and simulated in terms of steady state and dynamic behaviors. Various capacities and different modes of variable speed wind turbines are simulated and investigated. Case studies demonstrate how feeder voltages are influenced by capacity and control modes of wind turbines and changes in wind speed under various network conditions, and show harmonic impacts on the feeder. Modeling and simulation analysis is based on PSCAD/EMTDC a software package.

• 한국신재생에너지학회:학술대회논문집
• /
• 2007.06a
• /
• pp.366-369
• /
• 2007

This paper presents the general results of the conceptual design of a 3MW class offshore wind turbine named WinDS 3000 under development. In WinDS 3000, an integrated drive train design, three stage gearbox and permanent magnet generator (PMG) with fully rated converters have been introduced. A pitch regulated variable speed power control with individual pitch control has been adopted to regulate rotor torque while generator reaction torque can be adjusted almost instantaneously by the associated power electronics. Through the introduction of WinDS 3000, it is expected that helpful to understanding of the development status of 3MW offshore wind turbine.

• Proceedings of the KIEE Conference
• /
• 2004.07d
• /
• pp.2307-2309
• /
• 2004

This paper presents a modeling and simulation of a fuzzy controller for maximum power extraction of a grid-connected wind energy conversion system with a link of a rectifier and an inverter. It discusses the maximum power control algorithm for a wind turbine and proposes, in a graphical form, the relationships of wind turbine output, rotor speed, power coefficient, tip-speed ratio with wind speed when the wind turbine is operated under the maximum power control. The control objective is to always extract maximum power from wind and transfer the power to the utility by controlling both the pitch angle of the wind turbine blades and the inverter firing angle. 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 angle and rotor speed, pitch angle, and generator output.

• The Transactions of the Korean Institute of Electrical Engineers B
• /
• v.51 no.8
• /
• pp.467-474
• /
• 2002

In this paper, a wind power simulator is designed and implemented. To realize the torque of wind blade, a DC motor is used as a variable torque input device. An induction machine is used as a generator of which speed is controlled to maintain the optimal tip speed ratio during wind speed change. Input torque of system is controlled by armature current of DC motor and speed is controlled by generator control unit using field oriented control algorithm. Various control algorithms such as MPPT, soft start up, the simulator reactive power control, can be developed and tested using the simulator.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2004.03a
• /
• pp.401-407
• /
• 2004

This study proposes a interim development result for the l-㎾ class small wind turbine system, which is applicable to relatively low wind speed regions like Korea and has the variable pitch control mechanism. In the aerodynamic design of the wind turbine blade, parametric studies were carried out to determine an optimum aerodynamic configuration which is not only more efficient at low wind speed but whose diameter is not much larger than similar class other blades. A light composite structure, which can endure effectively various loads, was newly designed. In order to evaluate the structural design of the composite blade, the structural analysis was performed by the finite element method. Moreover both structural safety and stability were verified through the full-scale structural test.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.19 no.2
• /
• pp.124-130
• /
• 2005

This paper presents the simulation modeling and analysis of variable wind speed turbine system(VWTS) using Psim program In the simulation, using the Vestas V47 VWTS located in Hangwon wind farm in Jeju-Do as a model, wind model, blade model, pitch control model and grided connected generator are modeled. The VWTS is controlled by the optimal pitch angle for maximum output power under the rated wind speed and for the rated output power over the rated wind speed. To verify the effectiveness of proposed method, simulation results are compared with the actual data from the model system According to the comparison of these results, this method shows excellent performance. So it is very useful for understanding and applications of wind power control system.