[Objective] In the context of ongoing energy transition

photovoltaic power generation has attracted significant attention due to its clean and environmentally friendly nature

and its penetration rate in the energy sector continues to rise. However

the randomness and volatility of its output pose challenges to the stable operation of the power system. To address issues such as slow dynamic response and poor stability caused by grid-connected photovoltaic power generation units

a photovoltaic hybrid energy storage system is proposed. [Methods] With a focus on photovoltaic power generation

a hybrid energy storage system was introduced on the DC side of photovoltaic inverter. Considering the working characteristics of battery and supercapacitor

they were connected to the DC bus through a DC/DC converter using an active connection method. A separate frequency division control strategy was developed for the energy storage unit. Maximum power point tracking (MPPT) control was applied to the Boost converter of the photovoltaic power generation unit

and a strategy based on virtual synchronous generator (VSG) control was proposed to achieve grid connection of photovoltaic inverter. This paper established the VSG mathematical model in the two-phase synchronous rotating coordinate system

analyzed the impact of moment of inertia J and damping D on the system

pointed out the improvement methods

derived the adaptive parameter expression

and designed key parameters in the system. Finally

a grid-connected simulation model of photovoltaic hybrid energy storage was established in Matlab/Simulink. The active power output of the system was analyzed under the improved adaptive VSG control strategy proposed in this paper and the traditional VSG control strategy

with constant external conditions. Additionally

the stability of the entire system was analyzed under the given values of changing light intensity

load jump

and active power command jump. [Results] By observing the corresponding waveforms of each module

it is shown that the developed system can adjust the charging and discharging power of the battery in real time based on the relationship between photovoltaic output and load demand

ensure the power balance

and maintain the voltage stability of the bus. The proposed improved adaptive VSG control strategy not only considers the change in moment of inertia

but also takes into account the change in damping coefficient

which allows it to simultaneously suppress the frequency deviation rate and variation. Compared to the traditional VSG control strategy

it can further improve the frequency response and active power output response characteristics. The photovoltaic hybrid energy storage frequency division control can rapidly mitigate the power fluctuations in the system and make full use of the working characteristics of the energy storage system to maintain stable operation

which is conducive to extending the service life of the battery. [Conclusion] The simulation results strongly validate the feasibility and advantages of the proposed improved adaptive VSG control strategy in optimizing the operational efficiency of the photovoltaic hybrid energy storage system and supporting the reliable grid connection of distributed photovoltaic systems. Moreover

it provides new insights and technical support for the stable management and control of new energy power systems.