Abstract: Direct-drive wind power generation，as a common form of wind power generation，is expected to lead to a continuous decrease in the effective inertia of the receiving power grid as its capacity increases，exhibiting weak damping characteristics and increasing the operational risk of the power system.The use of grid control with active support capability in the flexible and direct grid connection process of direct-drive wind farms has gradually become the mainstream of research.However，due to its control technology and engineering applications being still in the research stage，it is necessary to first test them in simulation software.The grid connected system of grid structured direct-drive wind farm needs to consider the operation characteristics of a large number of wind turbines.The access of multiple units leads to a complex simulation operation environment，and the calculation force of hardware-in-the-loop simulation system is insufficient to meet the detailed simulation requirements of multiple units.To reduce computational pressure and find amore suitable simulation model for wind farm grid connection research，this paper simplifies the detailed model of direct-drive wind turbine units under grid control，and employs a controlled current source to replace the fan side model，further saving computer computing power.The model is compared from three aspects：input power，DC voltage，and AC voltage fluctuations.The detailed and simplified models from the perspectives of model response curve error and simulation time are evaluated.Our simulation results show the simplified model reflects the power output characteristics of thewind turbine grid side and has obvious advantages in saving simulation time.