Direct Torque Control of a Doubly-Fed Induction Generator for Variable Speed Wind Turbines

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.