Research On Frequency Control Of Grid-Connected Wind Farm

To eliminate the negative influence of fluctuating wind power on the grid, achieve the connection of large scale wind farm to power grid and make the wind power participate in the frequency control of the system, the active power and frequency control methods of grid-connected wind farm are studied in this paper. The control method by using flywheel energy storage could economize the fast response ability of flywheel energy storage system (FESS), and good control effect can be obtained when active power and frequency control of wind farm is conducted assisted by FESS.A permanent magnet synchronous motor based flywheel energy storage system is designed in this paper. Vector control method is adopted in the PMSM to achieve the accurate and effective electromagnetic torque control. Rotate speed control module is design to ensure the safe operation of the flywheel. The reference power calculation method of FESS when it assist wind farm with active power and primary frequency control is studied. The operation state of the FESS changes according to the change of reference power. And by controlling the grid side converter, the energy exchange between grid and storage system and unit factor operation are achieved. Space voltage vector control technology is adopted in both converters. Control models of FESS are established in Simulink, and simulation of active power and frequency control of wind farm are conducted. The result shows that this control method could effectively smooth the output of wind farm, and decreases the frequency deviation of grid as well.