Research on Reactive Power Control of the Grid-Side Converter of DFIG Based Wind Farm

During the grid fault, the rotor-side converter of the doubly-fed wind turbine exits the operation under the protection of the rotor and cannot generate reactive power. For this problem, this paper analyzes the mathematical model and reactive power regulation capability of the grid-side converter, two effective control models are proposed to ensure that the wind farm can still provide reactive power to the grid and keep the system running stably during the fault. In this paper, a three-machine nine-node system including a doubly-fed wind farm is established in the DIgSILENT/Power Factory simulation software, the simulation results show that the traditional unit power factor control mode of the grid-side converter can not meet the reactive power demand of the power grid during the grid fault. However, the two control methods proposed in this paper can generate more reactive power and achieve rapid recovery of voltage, which improves the transient voltage stability of the wind power access system to a certain extent. Finally, the two control methods of the grid-side converter are analyzed and compared from the aspects of reactive power regulation capability and dynamic response characteristics, and the best control method is proposed.