Optimal performance of double fed induction generator in windmills

Double fed induction generator with two pair of poles (DFTPPIG) can be combined with the windmill such that it works only at one power characteristic with the optimum value of tip speed ratio (TSR). With such construction one does not have to care on variable speed gearbox and variable pitch blade. Adjusting the magnitude of the rotor's voltage, angle between the rotor's ems and voltage and number of poles of the DFTPPIG in relation to the speed of the wind (shaft) it is possible to obtain the optimum value of TSR for wide range of speed for given windmill at the fixed position of the propellers.