Abstract: When large capacity DC loads and high permeability distributed generation are connected to the low voltage side of the solid state transformer,the high-voltage grid-connected interface tends to exhibit low inertia and poor damping characteristics,which reduces its grid-connection friendliness and operational reliability. To solve this problem,a modular multilevel converter（MMC）-type solid state transformer controlled by virtual synchronous generator technology was proposed. Firstly,the principle of virtual synchronous generator was analyzed,and the equivalent mathematical model of MMC and virtual synchronous generator was deduced,and the virtual synchronous generator technology was integrated into the control strategy of the input stage,which enhances the inertia and damping of the grid-connected interface,presenting a friendly and flexible buffering capability to the upper grid when the power at the output side changes. Secondly,In order to improve the frequency support capacity of the MMC-type solid-state transformer to the upper-level power grid,the energy storage device was configured on the low-voltage DC bus,and the primary frequency control was actively responded by varying the charging and discharging power. Then,through the reactive power control of the input stage,it was verified that it has a certain voltage regulation capability. Finally,a simulation model was built to verify the effectiveness and feasibility of the proposed control strategy.