Analytical determination of steady-state converter control laws for wind turbines equipped with doubly fed induction generators

An analytical method for the determination of the steady-state control laws of the doubly fed induction generators (DFIG) used in wind turbines is presented. The analytical model is used to derive the converter control laws of the generator in terms of rotor voltage and control angle (real and reactive power) on the whole operation speed range. The method can be efficiently implemented in a global optimisation CAD environment to design the converters and the generator associated to a given wind turbine. It is used to present some DFIG performances for different grid specifications and discuss the relative size of the rotor and grid side converters for a fixed induction generator and a given wind turbine of 2.5 MW.