An active power-frequency response optimization strategy for fractional-order VSG grid-connected system based on loop reconfiguration mechanism

The fractional-order virtual synchronous generator (FOVSG) increases the system’s tunable parameters by introducing a fractional-order virtual inertia control loop. However, its grid-connected active power -frequency (GCAPF) response still exhibits dynamic oscillation and overshoot under disturbances, such as internal active power command steps and external grid frequency fluctuations. To address this, this paper proposes an optimization control strategy for FOVSG based on the loop reconstruction mechanism (LRM-FOVSG). By flexibly adjusting three control degrees of freedom—active power feedback, feedforward channel correction, and fractional-order tuning parameters—the proposed LRM-FOVSG effectively suppresses system oscillations and overshoots, while significantly reducing the active power regulation time. Quantitatively, the proposed strategy effectively eliminates active power overshoots under both P ref and f g step disturbances, achieving a rapid frequency recovery time of 0.072 s. Finally, both MATLAB simulations and experimental results are presented to verify the effectiveness and superiority of the proposed strategy in enhancing the system’s power-frequency dynamic performance.