With the increasing penetration of renewable energy and power electronic devices in power systems, this paper proposes a virtual synchronous generator frequency regulation strategy that combines a radial basis function adaptive method with model predictive control, using a photovoltaic-energy storage system as an example. Based on the dynamic adjustment of system rotational inertia and damping coefficient, a three-step frequency prediction model is established, introducing the system angular frequency deviation and active power as external inputs. Through rolling optimization by the model predictive controller, the compensation power of the virtual synchronous generator is optimized to dynamically correct the reference power. On the DC side, the photovoltaic and energy storage units jointly supply power, ensuring stable active power output of the virtual synchronous generator and maintaining DC bus voltage regulation. Simulation results demonstrate that the proposed strategy effectively suppresses active power oscillations in the photovoltaic-energy storage grid-connected system, reduces frequency deviation and its rate of change, and meets the frequency regulation requirements of high-penetration renewable energy systems.