Frequency Regulation Capability Improvement Control Strategy for Grid‐Forming Direct‐Drive Wind Turbines

Grid‐forming control of direct‐drive permanent magnet synchronous generator (D‐PMSG) wind turbine is an effective method to improve the frequency stability and provide inertia support for the system. In conventional virtual synchronous generator (VSG)–based grid‐forming control, fixed inertia and droop coefficients can result in poor frequency regulation under varying frequencies, and excessive reduction in rotor speed may lead to disconnection. This study analyzes the frequency support capability of rotor kinetic energy and the speed recovery characteristics of VSG‐based D‐PMSGs. It proposes a frequency support strategy for D‐PMSG that uses Adaptive Sliding Mode Extended State Observer (ASM‐ESO) to enhance the frequency regulation capability and reduce the risk of secondary frequency drops during rotor speed recovery. A grid‐forming D‐PMSG system based on the RT‐LAB platform is adopted to conduct the proposed frequency support strategy performance evaluation.