High Voltage Ride-Through Control Strategy for DFIG Considering Full Magnetic Flux Linkage Compensation
When the power grid voltage surges,the stator flux changes dynamically in the doubly fed induction generator(DFIG),resulting in degraded performance of the traditional vector decoupling control.In this paper,by establishing the precise mathematical model of DFIG,the disturbance terms and coupling terms related to the flux are obtained through comparative analysis.Based on this,the traditional vector decoupling control is improved,and a control structure with full flux compensation is proposed to improve the high voltage ride through(HVRT)capability of the wind power system.By breaking the constraint of vector orientation,the decoupling term calculated directly from the measured current value and the stator flux compensation term multiplied by the compensation coefficient defined in this paper are introduced as feedforward compensation means to correct the instruction value of the inner current loop.The simulation results show that the proposed full flux compensation control strategy can quickly track the internal flux change when the power grid voltage surges,suppress the instantaneous influence caused by the power grid voltage sudden change,accelerate the oscillation attenuation speed,and have good transient response characteristics,which is conducive to DFIG to realize fault ride through.