This paper presents an equivalent synchronous generator model (ESGM) of current-controlled (CC) voltage source converters (VSCs) for small signal stability analysis, addressing the pivotal dynamic of the universal phase-locked-loop (PLL). The virtual electromechanical swing process of PLL-based CC-VSC is revealed, which is utilized to emulates the behavior of traditional SG, and the ESGM (including inertia constant, synchronizing coefficient, damping coefficient, and power-angle curve) is developed accordingly. It provides the foundation of migrating the well-developed theories and methodologies of traditional power system to investigate the frequency and power angle stability of the VSC-based system or the hybrid system containing several VSCs and traditional SGs.