• Journal of Power Electronics
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• v.17 no.4
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• pp.1027-1036
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• 2017

The brushless doubly-fed induction generator (BDFIG) is a new type of dual stator winding induction generator. In such a generator, both the power winding (PW) and the control winding (CW) are housed in the stator. This paper presents the performance characteristics of a stand-alone BDFIG operation system. A new T-type steady-state model of a BDFIG is proposed. This model is more suitable for the performance analysis of stand-alone BDFIGs than the conventional Π-type steady-state model and the simplified inner core steady-state model. The characteristics of the power flow and CW current are analyzed by detailed mathematical derivations on the basis of the proposed T-type steady-state model. The analysis results are verified by experiments, which are carried out on a prototype BDFIG. The results of the performance analysis contribute to simplifying the control circuit, improving the control performance, and selecting an appropriate BDFIG for actual industrial applications.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.261-264
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• 2006

In this paper, doubly-fed induction-type wind power generation system simulation model for grid connection is developed. The simulation model is based on PSCAD/EMTDC and consists of rotor-blade, blade controller, generator power converter and generator controller Blade controller controls the blade pitch angle for starting, peak power limiting and emergency condition. Generator controller controls the generator output power to maximize the system efficiency. Simulation results are shown for the variable wind speed conditions. The simulation model can be utilized for study of actual interaction between wind turbine and grid for reliable operation and protection of power system.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.40 no.7
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• pp.656-663
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• 1991

This paper deals with the control strategy for the constant voltage, constant frequency (CVCF) generation of doubly -fed induction generator. Since induction machine is a nonlinear and multivariable one, the influential factors for CVCF generation of induction generator are the magnitude of output voltage, load current and its power factor, slip of the machine, etc. To get appropriate control scheme and study the effect of its parameters, the control equation of induction machine is derived and tested. The simulation and test results show that suggested equation and control system are very useful strategy for the CVCF control of induction generator.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.639-643
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• 2003

We are interested in this paper on the control of an electromechanical system consisting of a doubly-fed induction generator(DFIG), driven by a prime mover that can supply or extract mechanical power, e.g., a flywheel inertia, and an induction motor(IM). The stator of the Induction machine is connected to the stator of the generator whose rotor voltage is regulated by a bidirectional converter. The main interest of this configuration is that it permits a bidirectional power flow between the motor, which may operate in regenerative mode, and the generator We propose a passivity-based controller to regulate the motor mechanical speed. Since this kind of controllers achieve stabilization via energy balancing, regulation of the power flow in the system is naturally incorporated. Simulation results are presented to illustrate the main points of our paper.

• Journal of Power Electronics
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• v.8 no.1
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• pp.10-22
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• 2008

The wind-driven doubly fed induction generator (DFIG) is currently under pressure to be more grid-compatible. The main concern is the fault ride-through (FRT) requirement to keep the generator connected to the grid during faults. In response to this, the paper introduces a novel model and new control scheme for the DFIG. The model provides a means of direct stator power control and considers the stator transients. On the basis of the derived model, a robust linear quadratic (LQ) controller is synthesized. The control law has proportional and integral actions and takes account of one sample delay in the input owing to the microprocessor's execution time. Further, the influence of the grid voltage imperfection is mitigated using frequency shaped cost functional method. Compensation of the rotor current pulsations is proposed to improve the FRT capability as well as the generator performance under grid voltage unbalance. As a consequence, the control system can achieve i) fast direct power control without instability risk, ii) alleviation of the problems associated with the DFIG operation under unbalanced grid voltage, and iii) high probability of successful grid FRT. The effectiveness of the proposed solution is confirmed through simulation studies on 2MW DFIG.

• Wind and Structures
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• v.22 no.6
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• pp.635-662
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• 2016

This paper deals with the comparison of different control strategies for the Induction generators in wind energy conversion system. Mainly, two types of induction machines, Self excited induction generator (SEIG) and doubly Fed Induction generators (DFIG) are studied. The different control strategies for SEIG and DFIG are compared. For SEIG, Electronic load Controller mechanism, Static Compensator based voltage regulator are studied. For DFIG the main control strategy namely vector control, direct torque control and direct power control are implemented. Apart from these control strategies for both SEIG and DFIG to improve the performance, the ANFIS based controller is introduced in both STATCOM and DTC methods. These control methods are simulated using MATLAB/SIMULINK and performances are analyzed and compared.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.460_461
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• 2009

This paper analyzes the steady state characteristics for variable speed wind power system with doubly-fed induction generator(DFIG). This paper explains the equivalent circuit and phasor diagram of DFIG for different operating conditions. It also simulates the torque-slip characteristics with respect to changes of different parameters. Simulation results show the torque-slip characteristics, stator power factor-rotor voltage and stator current-rotor voltage.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1182-1183
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• 2008

In this paper, we develop PCS for doubly-fed induction-type wind generator(DFIG). PCS consists of a converter set and a controller. PCS controls the active power of wind generator and the reactive power of wind turbine system according to rotating speed, instantaneous power, grid quality, and order by transmission system operator.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.6
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• pp.985-993
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• 2008

This paper proposes a new DFIG(Doubly-Fed Induction Generator) system using matrix converter, which is very effectively used for interconnecting the wind power system to the power grid. The operation of proposed system was verified by computer simulations with PSCAD/EMTDC software. The feasibility of hardware implementation was conformed by experimental works with a laboratory scaled-model of wind power system. The laboratory scaled-model was built using a motor-generator set with vector drive system, and a matrix converter with DSP(Digital Signal Processor). The operation of scaled-model was tested by modeling the specific variable-speed wind turbine using the real wind data in order to make the scaled-model simulate the real wind power system as close as possible. The simulation and experimental results confirm that matrix converter can be applied for the DFIG system.

• Advances in Computational Design
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• v.8 no.3
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• pp.237-253
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• 2023

Torque ripple content and variable switching frequency operation of conventional direct torque control (DTC) are reduced by the integration of space vector modulation (SVM) into DTC. Integration of space vector modulation to conventional direct torque control known as SVM-DTC. It had been more frequently used method in renewable energy and machine drive systems. In this paper, SVM-DTC is used to control the rotor side converter (RSC) of a wind driven doubly-fed induction generator (DFIG) because of its advantages such as reduction of torque ripples and constant switching frequency operation. However, flux and torque ripples are still dominant due to distorted current waveforms at different operations of the wind turbine. Therefore, to smoothen the torque profile a Neural Network Controller (NNC) based SVM-DTC has been proposed by replacing the PI controller in the speed control loop of the wind turbine controller. Also, stability analysis and simulation study of DFIG using process reaction curve method (RRCM) are presented. Validation of simulation study in MATLAB/SIMULINK environment of proposed wind driven DFIG system has been performed by laboratory developed prototype model. The proposed NNC based SVM-DTC yields superior torque response and ripple reduction compared to other methods.