基于惯性同步的变流器跟/构网一体化控制及振荡稳定性研究OA

Grid-following(GFL)converters rely on phase-locked loop(PLL)to achieve synchronization and are prone to oscillatory instability under weak-grid conditions.To address the instability of GFL control in weak grids,this paper introduces a grid-forming(GFM)inertia synchronization control(ISC)mechanism into the conventional PLL-based GFL control framework,and proposes an integrated GFL/GFM synchronization control method.First,the principles of ISC and the integrated GFL/GFM control strategy are elaborated.Then,a small-signal model of the integrated GFL/GFM converter is established,and the participation factor analysis is adopted to reveal the mechanism of PLL-ISC coupling on system stability under variations of GFL/GFM weights in weak grids.Subsequently,root locus analysis is performed to investigate the influence of control parameters,grid strength,and operating conditions on unstable modes,and the improvement effect of increasing ISC control weight on system stability under weak grid conditions is quantitatively analyzed.Theoretical results demonstrate that the proposed integrated control effectively suppresses PLL-induced oscillations in weak grids and enhances the operation capability,significantly outperforming pure GFL control.Finally,the validity of the analysis is confirmed by detailed time-domain EMT simulations in PSCAD/EMTDC.