  To satisfy dynamic requirements of power systems, it is imperative for
grid-tied inverters to ensure good disturbance rejection performance (DRP)
under variable grid conditions. This letter discovers and theoretically proves
that for general networks, synthesizing grid-following (GFL) inverters and
grid-forming (GFM) inverters can always more effectively ensure the DRP of
multiple inverters, as compared to homogeneous inverter-based systems that
solely utilize either GFL or GFM inverters. The synthesis of GFL inverters and
GFM inverters can concurrently increase the smallest eigenvalue and decrease
the largest eigenvalue of the network grounded Laplacian matrix. This can be
equivalent to rematching the proper short-circuit ratio (SCR) for GFL and GFM
inverters, thereby ensuring the DRP of inverters both in weak and strong grids.
The results reveal the necessity of synthesizing diverse inverter control
schemes from the network-based perspective. Sensitivity function-based tests
and real-time simulations validate our results.
