Simulation of Low Voltage Ride through for Doubly Fed Induction Generator Based on Model Analysis
In response to the problem of overcurrent in the rotor side converter of a doubly fed induction generator caused by asymmetric voltage drop in the power grid,based on the mathematical model and transient parameter analy-sis of the doubly fed induction generator in a synchronous coordinate system with forward and reverse rotation,it is de-rived that the change in positive sequence current is much greater than that in negative sequence under the same volt-age change in the rotor positive and negative sequence,and the stator reactive power generated by the doubly fed in-duction generator is positively correlated with the rotor positive sequence reactive current.A asymmetric low-voltage ride through control strategy that balances rotor current and grid reactive power support is proposed.The model is au-tomatically and dynamically solved during the ride through period to reasonably distribute the rotor voltage and control the rotor fault current within the safe range.Finally,the feasibility of the strategy is verified by MATLAB/Simulink.When the voltage drops by 80％,the rotor current is controlled to provide maximum reactive power support to the pow-er grid at the same time to help the power grid voltage recover.The proposed control strategy improves the low voltage ride-through capability of DFIG to a certain extent.
Asymmetric drop of grid voltageElectric currentReactive power supportLow voltage ride through
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