High-voltage direct-mounted grid-forming energy storage is a key device for solving voltage and frequency in new energy power systems. Under large disturbance conditions

the rapid changes in grid voltage and frequency require rapid support and disturbance rejection capabilities. In this paper

a mathematical model for high-voltage direct-mounted energy storage under large disturbance conditions based on its topology is set up firstly. On this basis

a control strategy for high-voltage direct-hung grid-forming energy storage based on sliding mode control is proposed

which addresses the chattering problem by improving the sliding surface and the reaching law function. Additionally

a sliding mode control based on a power function is proposed. Finally

a Lyapunov function is set up to prove that the improved sliding mode grid-forming control strategy meets the stability conditions. The simulation results show that compared with the grid-forming control system using a proportional-integral controller

the modular cascaded high-voltage direct-mounted grid-forming energy storage system using the improved sliding mode control has stronger disturbance resistance capabilities and voltage support effects.