Application of Direct Controls to Variable–Speed Wind

Abstract

The well–known principle of the direct torque control applied mainly to squirrel–cage induction motor drives can be generalized and applied to other machines, quantities, converters and systems. These are: other AC machines (double–fed induction and permanent magnet synchronous machine), active and reactive power, direct power control of the line side converter, direct controls of both of the converters in a DC link inverter. These new fields are investigated in this paper generally and their application to the components of a wind generator practically. The limits of the direct torque control in salient–pole permanent magnet synchronous generator are given. A solution is given for the stability problem of the double–fed induction generator. The systems are investigated by simulation, the results show the excellent performance of the proposed controls.