RoCof droop control of PMSG-based wind turbines for system inertia response rapidly

Abstract

This paper proposes a RoCoF droop control, which relieves the transient frequency change process by controlling the energy of the DC side capacitor. Firstly, analyze and classify the control time scale of the wind power system (WPS). Under the electromagnetic time scale, combine the low-pass filter (LPF) and the differential link to obtain the control link of the system. Therefore, the transient process of RoCoF is effectively improved. Secondly, on the basis of the inertia analysis of the original synchronous generator, further derivation and analysis of the RoCoF droop control inertia characteristics. Compared with traditional droop control, RoCoF droop control enables the inverter to have the ability to improve frequency deviation. Then, the mechanism analysis of the bus capacitance voltage to the system inertia support is given, the relationship between capacitor reserve capacity and RoCoF is derived, which verifies the feasibility of capacitor-assisted frequency modulation. Finally, the experimental comparison with the droop control strategy is carried out based on the RT-LAB platform.