With the high proportion of renewable energy integrated into the power system, the system lacks the inertia traditionally provided by synchronous generators. Consequently, it cannot actively support voltage or maintain frequency stability, presenting new challenges for maintaining power quality within the power system. To maintain the stable operation of the power system, this paper addresses the fluctuating and unpredictable nature of photovoltaic (PV) power generation by constructing a grid-connected model of a PV energy storage system. Firstly, a grid-forming energy storage converter control strategy based on Virtual Synchronous Generator (VSG) control is proposed. Secondly, the Maximum Power Point Tracking (MPPT) algorithm control, energy storage battery control, and VSG control are analyzed. Then, a small-signal model of active power and its system transfer function are constructed. The conjugate eigenvalue trajectories of different D and J are further drawn, and the impact of D and J values on system stability in the VSG control strategy is analyzed and confirmed. Finally, simulations verify that the proposed strategy can accurately track active and reactive power commands, maintain stable DC voltage, and smooth the output of photovoltaic power sources, thus confirming the effectiveness of the grid-forming energy storage converter control strategy.