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The classical vector control technology is usually adopted in doubly fed induction generator (DFIG). As the stator flux linkage cannot change suddenly, the grid voltage asymmetrical dips will generate transient DC flux linkage on stator side. At the same time, high electromotive force induced on the rotor side by accompanying negative sequence flux linkage, may exceed the maximum voltage of the rotor side converter. Hence the current is out of control due to the saturated converter. To solve the problem, a dual control is studied in the paper which can optimize the fluctuation of rotor current, stator current and electromagnetic torque during asymmetrical grid voltage dips. A simulation model of DFIG is built on Matlab/Simulink platform, and the two kinds of control strategies are compared and analyzed on rotor current, stator current and electromagnetic torque. The simulation results verify the effectiveness of dual control.
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