Direct Torque Control of a Doubly-Fed Induction Generator for Variable Speed Wind Turbines
ABSTRACT This paper presents the analysis and design of a Direct Torque Control (DTC) of a Doubly-Fed Induction Generator applied to a wind generation system as an alternative to the classical field-oriented control (FOC) widely used in drive control. The aims of the control system are the control of the reactive power interchanged between the generator and the grid and the control of the power drawn from the wind turbine in order to track the wind turbine optimum operation point. DTC appeared as a control concept for squirrel cage motor drives. In this paper, DTC concept is applied to control a wound rotor induction generator by means of a rotor connected VSI. Torque and rotor flux control are used to control in an indirect way active and reactive power, respectively.
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ABSTRACT: The aerodynamic torque and power caused by the interaction between the wind and blade of wind turbine are highly nonlinear. For this reason, the overall dynamic behaviors of wind turbine have nonlinear characteristics. The aerodynamic nonlinearity also affects properties of torque control for wind turbine. In this paper, the nonlinear aerodynamic property according to the wind speed below rated power and its effects on the torque control system are investigated. Nonlinear parameter representing change of aerodynamic torque with respect to rotor speed is obtained by linearization technique. Effects of this aerodynamic nonlinear parameter on the closed-loop torque system with PI controller for an 1.5 MW wind turbine are presented.Journal of Institute of Control, Robotics and Systems. 01/2009; 15(12).
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ABSTRACT: in this paper, the Authors present a Direct Torque Control scheme of an Induction Generator (IG) associated with a wind turbine system. The turbine is used to drive the IG in order to feed an isolated DC load. It receives the required active power from the generator through a rectifier and a DC bus. The models of the system components are developed and used in the system control scheme. Mathematical relations treating the system components are presented and studied. The generator and the turbine dynamic performances are analyzed. The simulation results of the system entire control have shown that the proposed methodology is an efficient and promising control procedure.IEEE Electrotechnical Conference (MELECON), 2012 16th IEEE Mediterranean. Date 25-28 March 2012; 03/2012
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ABSTRACT: As the wind has become one of the fastest growing renewable energy sources, the key issue of wind energy conversion systems is how to efficiently operate the wind turbines in a wide range of wind speeds. Compared to fixed speed turbines, variable speed wind turbines feature higher energy yields, lower component stress and fewer grid connection power peaks. Generally, measurement of wind speed is required for the control of variable speed wind turbine system. However, wind speed measured by anemometers is not accurate owing to various reasons. In this work, a new control algorithm for variable speed wind turbine system based on Kalman filter which can be used for the estimation of wind speed and artificial neural network which can generate optimum rotor speed is proposed. Also, to verify the feasibility of the proposed scheme, various simulation studies are carried out by using Simulink in Matlab.Journal of Korean Institute of Intelligent Systems. 04/2010; 20(2).