This paper analyzes the core equipment and charging systems of electric vehicle charging stations, and sets up a charger model with voltage source PWM rectifier, phase shift full bridge ZVS DC converter and other equipment in Matlab/Simulink. The average switching model and the impedance model are proposed to simplify the charging systems. Through dynamic simulation comparison, the average switching model is found effictive to simulate the transient response characteristics of charging stations. On this basis, a control method combining the droop control and voltage support control is proposed for charging stations to participate in voltage regulation. With the single-machine infinite system and the IEEE 33-bus system constructed on MATLAB/Simulink platform, it is demonstrated that the proposed method can support the voltage in both static and transient conditions. When the grid voltage drops, reactive power support could be provided to improve the voltage quality and stability of the system.