Research on SSO Suppression Strategy of Grid‐Forming D‐PMSG Based on Adaptive Notch Filter

ABSTRACT Subsynchronous oscillations (SSOs) within the power grid can compromise the control efficacy of the grid‐side converter for direct‐drive permanent magnet synchronous generators (D‐PMSGs) operating in grid‐forming mode. Consequently, the system's stability is at risk. To mitigate this problem, an adaptive notch filter (ANF)–based strategy for SSO reduction has been introduced. Initially, the effects of grid‐based SSOs on the grid‐side control of D‐PMSGs, utilizing virtual synchronous machines, were investigated, including the analysis of how SSO characteristics influence the efficacy of notch filters. Subsequently, an algorithm for SSO parameter identification was developed, enhancing the fast Fourier transform (FFT) to accommodate the dynamic frequency changes of SSOs. This led to the creation of an ANF center frequency updating approach, which was informed by the parameter identification results. The most effective location for ANF intervention within the control system was also identified. The proposed control strategy's capability to suppress SSOs was validated through the development of simulation models and the establishment of experimental setups.