المستخلص: |
This paper proposition a control planner of a grid connected doubly fed induction generator (DFIG) wind turbine with series grid side converter (SGSC) to improve the control and operation performance of (DFIG) system through grid unbalanced. The action of (DFIG) system with (SGSC) under unbalanced grid voltage condition is described. The (SGSC) is controlled to input voltage in series to balance the stator voltage. So that, the reverse impact of voltage unbalance in the (DFIG) such large stator and rotor current unbalances, electromagnetic torque and power pulsations are removed and the conventional vector control strategy for the rotor side converter (RSC) remains in full force under unbalanced conditions. Meanwhile, three selective control targets for the parallel grid side converter (PGSC) such eliminating the oscillations in total active or reactive power, or no negative sequence current inputted to the grid are identified and compared. Besides, the proportional resonant controllers in the stationary reference frame are designed for both the (SGSC) and (PGSC) to further improve the dynamic performance of the whole system. Finally, the rating and losses of the (SGSC) and the inputted transformer are discussed and the effectiveness of the proposition control planner is verified by the simulation results of using average model in Matlab a 6×1.5 MW (DFIG) based wind turbine with (SGSC) under steady state and small transient grid voltage unbalance.
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