Grid forming (GFM) voltage source converters (VSC) based on the power synchronization control (PSC) are used to support the grid by emulating the power angle characteristics of synchronous machines. However

they face oscillation risks under wide range of short-circuit ratio (SCR) conditions. To analyze the stability of GFM converters under wide range SCR conditions

this paper establishes a small-signal PSC-VSC model

and the transfer functions of active and reactive power are derived. Based on this

the small-signal instability mechanism of GFM converters under wide range of SCR conditions is revealed. The results show that PSC-VSC faces small-signal instability risks in strong grid conditions. Subsequently

by limiting the gain of the active power transfer function

the power self-synchronization control (PSSC) based VSC control strategy is proposed to enhance the stability of GFM converters in strong grid conditions. Furthermore

the stability of PSSC-based GFM converters under grid faults is analyzed. Finally

the correctness and effectiveness of the proposed analysis method are verified through hardware-in-the-loop real-time simulation.