With the large-scale development of electric vehicles, the ratio of the peak electric vehicle charging load to the total network load is rising day by day, which would have a negative impact on the static voltage stability of the power gird. This paper attempts to incorporate electric vehicle charging equipment into power system control, thereby reducing this negative impact. Firstly, three kinds of EV charging control method are proposed and their control effects are compared. The simulation and comparison show that all the three kinds of control methods could increase the load margin of the power grid, but the droop control method is more suitable for practical use. Then the droop control method is applied to New England 39-bus system to analyze its effect on load margin under different permeability and charging rate. The results show that the droop control method could increase the load margin obviously, it is an effective method for electric vehicle charging equipment local control.