Frequency Trajectory Planning Based Transient Frequency Support of D-PMSG

Abstract

The grid connection of large-scale wind power will reduce the equivalent inertia and damping of the system, resulting in a decrease in system frequency stability. The directly-driven permanent magnet synchronous generators (D-PMSG)-based wind turbine (WT) usually uses conventional PD control to support frequency, however, the related controller parameters are difficult to design, reducing economic benefits of WT power generation and slowing speed recovery. To this end, based on the analysis of the dynamic response of D-PMSG grid-tied system, this paper studies the dynamic influence and variation law of controller parameters on system frequency. A WT control strategy based on frequency trajectory planning (FTP) is proposed. The frequency fixed value determined by the power grid regulation is directly taken as the control target to carry out the FTP, and the WT auxiliary power output is controlled according to the planned frequency trajectory. The system frequency is supported quickly in the transient process, ensuring the safe and stable operation of the grid while realizing the economy of WT power generation. The effectiveness and economy of the proposed control strategy is verified by RT-LAB experiment.