This article takes household photovoltaic energy storage systems as the research object. In order to improve the economy of household photovoltaic energy storage systems, the photovoltaic modules always work in MPPT mode with constant output power. Therefore, the task of maintaining system power balance is mainly completed by the energy storage system. In order to suppress the imbalance of DC microgrid bus voltage during power fluctuations, virtual inertial control is usually used in energy storage systems. This method increases the damping and inertia of the system, and achieves the effect of suppressing bus voltage fluctuations by slowing down the response time. This article establishes the transfer function of the energy storage system, compares the stability of PI control and virtual inertial control, and designs specific parameters for the virtual inertial control of the energy storage system through root locus and Bode diagrams. This parameter design method can obtain the optimal parameters of virtual inertial control, thereby enabling the energy storage system to have good stability while also having fast dynamic response characteristics. Finally, the correctness of the parameter design was verified through experiments.