Improving waveform quality in direct power control of DFIG using fuzzy controller

This paper proposes a new direct power control (DPC) strategy of double-fed induction generator using fuzzy logic controller. The active and reactive power equations are expanded, and effects of voltage vectors on active and reactive power variations are investigated quantitatively. The selection of the voltage vectors is performed using fuzzy system which is used instead of optimal switching table. Four variables are used as inputs of the fuzzy system which are errors of active and reactive powers, real time value of the rotor speed and stator flux position. The defuzzified output is the optimal selected voltage vector. MATLAB/Simulink software is used for the purpose of simulation and the results reported show the effectiveness of the proposed method in improving the waveform quality. Compared with the conventional DPC, the proposed fuzzy technique can reduce the power out of band percentage by about 25 % which is very impressive.