New energy grid connection is easy to cause voltage fluctuation, frequency oscillation and other problems. For this, the paper adopts a frequency division control strategy of hybrid energy storage unit, which based on the storage of photovoltaic grid-connected system as the research subject, thus improving the dynamic stability of DC bus voltage, and proposes an improved virtual synchronous generator. According to the characteristics of flexible adjustment of inertia parameters, the virtual inertia and parameters are adjusted adaptively to suppress the frequency and power oscillation caused by the disturbance. Finally, a simulation model of photovoltaic storage grid-connection is established. It verifies that the proposed strategy can not only stabilize the DC bus voltage and supplement the power deficiency under different operating conditions. At the same time, it can slow down the sudden change of the system frequency and reduce the overshoot, showing good grid-connected performance.