• Journal of Electrical Engineering and Technology
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• v.9 no.3
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• pp.820-826
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• 2014

It is well known that energy generated by a wind generator (WG) depends on the wind resources at the installation site. In other words, a WG installed in a high wind speed area can produce more energy than that in a low wind speed area. However, a WG installed at a low wind site can produce a similar amount of energy to that produced by a WG installed at a high wind site if the WG is designed with a rated wind speed corresponding to the mean wind speed of the site. In this paper, we investigated the power curve of a WG suitable for Korea's southwestern coast with a low mean wind speed to achieve a high capacity factor (CF). We collected the power curves of the 11 WGs of the 6 WG manufacturers. The probability density function of the wind speed on Korea's southwestern coast was modeled using the Weibull distribution. The annual energy production by the WG was calculated and then the CFs of all of the WGs were estimated and compared. The results indicated that the WG installed on the Korea's southwestern coast could obtain a CF higher than 40 % if it was designed with the lower rated speed corresponding to the mean wind speed at the installation site.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.26 no.4
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• pp.48-56
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• 2012

The object of this paper is the controller for supplying stably power in a separate house in which a hybrid electrical storage system with a stand-alone photovoltaic/wind power generation system and a small generator is applied. In the photovoltaic/wind hybrid power system used in the separate house, when only the battery is used in sunless days, the capacity of the battery is become larger. In particular, as in recent days, if cloudy days are frequent due to anomaly climate, it is difficult to estimate the number of sunless days. Accordingly, it is preferable to build the electrical storage system that numbers of sunshineless days are to be controlled and a shortage amount of the power generation capacity is to be handled by a small generator system. In order to supply stably power of new renewable energy such as solar to any separate houses, it is preferable to reduce the capacity of battery by decreasing the number of sunless days when estimating the capacity of battery and to drive the small generator for compensation of the power shortage. Such system needs components including inverters for photovoltaic and wind power generation system, batteries and controllers for automatically driving the small generator, based upon the nature of the stand-alone house, and it is preferable to use the controller having a simpler and higher stability by adopting the all-in-one scheme to facilitate its maintenance.

• Proceedings of the KIEE Conference
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• 2003.04a
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• pp.143-145
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• 2003

In this paper, wind power system with direct-driven axial-flux type permanent-magnet (PM) synchronous generator, 10 [kVA], 300 [rpm], is presented. In order to analyze the performance of axial PM generator, finite-element (FE) analysis is used, and the 2-dimensional equivalent model is developed. The steady-state and transient-state characteristics are respectively analyzed at no-load and resistive-inductive loads. The test results of driving characteristics are presented as well. The results are very similar to predicted performance of design. Proposed generator is feasible for use with a small-class wind power applications.

• Journal of Power Electronics
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• v.10 no.5
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• pp.538-547
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• 2010

This paper deals with a stand-alone wind energy conversion system (WECS) with an isolated asynchronous generator (IAG) and voltage and frequency (VF) control feeding three-phase four-wire loads. The reference generator currents are estimated using the instantaneous symmetrical component theory to control the voltage and frequency of an IAG system. A three-leg voltage source converter (VSC) with an isolated star/delta transformer is used as an integrated VSC. An integrated VSC with a battery energy storage system (BESS) is used to control the active and reactive powers of the WECS. The WECS is modeled and simulated in MATLAB using the Simulink and the Sim Power System (SPS) toolboxes. The proposed VF controller functions as a voltage and frequency regulator, a load leveler, a load balancer and a harmonic eliminator in the WECS. A comparison is made on the rating of the VSC with and without ac capacitors connected at the terminals of an IAG. Simulation and test results are presented to verify the control algorithm.

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.121-123
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• 2002

This paper presents the finite-element (FE) analysis results of a permanent-magnet (PM) generator for wind-power applications under different operating conditions. Finite-element method is applied to analyze generator performance at no-load and load with variable resistance and inductance. The results of FE analysis show that proposed PM generator is a useful solution for small-scale wind-turbine systems.

• The Transactions of the Korean Institute of Electrical Engineers B
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• v.52 no.10
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• pp.528-534
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• 2003

A grid connection algorithm is proposed for the doubly-fed induction generator (DFIG) which is widely adopted in high power variable speed wind turbine. Before the stator of DFIG is connected to grid, rotor-side converter is used to control the induced stator voltage. As a result, the stator transient current is limited below the rate value during the connection by the proposed synchronization of the stator voltage to the grid voltage. A wind power generation simulator using DC motor and wound-rotor induction generator is built and the dynamic characteristics of proposed algorithm is verified experimentally.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.3
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• pp.405-410
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• 2015

This paper deals with the design method of 1kW-Switched Reluctance Generator (SRG) for wind power applications. The coefficient of the output equation is determined according to the purpose specification for design of SRG. Detailed design is carried out, after selecting the outer diameter of the rotor on the basis of the output equation. The generation characteristic of designed generator is verified by using Finite Element Method (FEM).

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1032-1039
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• 2001

In this paper, modal analysis of wind-power generator rotor system was performed by using finite element method. Experimental modal analysis of generator rotor system was performed and the result were compared with analytical ones. Sensitivity method and localized modification method were used to update finite element model. As a result of updating finite element model, errors of natural freguency were reduced within 0.5％ and MAC value was improved near by l. Stability characteristics of wind-power generator rotor-bearing system through harmonic analysis about several external force will be analyzed using finite element model.

• Proceedings of the KIEE Conference
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• 2002.07b
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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.

• Journal of Power Electronics
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• v.15 no.5
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• pp.1358-1366
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• 2015

This study focuses on an advanced second-order sliding mode control strategy for a variable speed wind turbine based on a permanent magnet synchronous generator to maximize wind power extraction while simultaneously reducing the mechanical stress effect. The control design based on a modified version of the super-twisting algorithm with variable gains can be applied to the cascaded system scheme comprising the current control loop and speed control loop. The proposed control inheriting the well-known robustness of the sliding technique successfully deals with the problems of essential nonlinearity of wind turbine systems, the effects of disturbance regarding variation on the parameters, and the random nature of wind speed. In addition, the advantages of the adaptive gains and the smoothness of the control action strongly reduce the chatter signals of wind turbine systems. Finally, with comparison with the traditional super-twisting algorithm, the performance of the system is verified through simulation results under wind speed turbulence and parameter variations.