Combined vector control and direct power control methods for DFIG under normal and unbalanced and distorted grid voltage conditions

In this paper, a new control method for rotor side converter (RSC) and grid side converter (GSC) of doubly fed induction generator (DFIG) is proposed. Using the main principle of vector control (VC) and direct power control (DPC) results in a new control strategy for the RSC. Instead of using DPC strategy for the GSC, a direct current control is applied. Under the unbalanced and distorted grid voltage conditions, the new control strategy injects a pure sinusoidal and balanced stator and GSC currents without any need of extracting the negative sequence and 5^th and 7^th voltage harmonics. Only a modified phase locked loop (PLL) to extract the positive sequence of the fundamental phase angle, is added to this situation. The accuracy of the proposed control strategy for 2 MW DFIG under normal and unbalanced and distorted voltage conditions is evaluated in MATLAB/SIMULINK environment and results are compared with DPC strategy.