Control Strategy of Wind Turbine Grid Side Converter under Unbalanced Grid Voltage
As the negative sequence component in the unbalanced power grid will have a huge impact on the normal operation of wind turbines,taking the doubly fed wind turbine in the wind-driven generators as an example,a control strategy was proposed by combining the double closed-loop control and sliding mode variable structure control in the grid side converter.The double closed loop control was formed by the control of the air control center and the network active disturbance rejection controller,which can maintain the stability of the converter voltage.By combining with sliding mode variable structure control,the influence of negative sequence components on the system was eliminated.Through experimental simulation,it had been verified that the dual closed-loop control strategy can output a sine wave that was consistent with the grid voltage.The proposed control strategy has a good inhibitory effect on the harm caused by single-phase short circuit faults.
wind turbinegrid side converterunbalanced grid voltagedoubly-fed asynchronous generatordouble closed-loop controlsliding mode variable structure control