Voltage coordination control method based on smooth switching of P-U-I controller

The invention discloses a voltage coordination control method based on P-U-I controller smooth switching, and the method comprises the steps: determining an AC active component and an AC reactive component according to a system power optimization reference value; a P-U-I controller is designed, all regulators adopt PI control, the delay effect of PWM control is considered, and an inertial link is introduced as approximate equivalence. According to the transfer functions of the approximate equivalence and current/voltage PI controller and the equivalent circuit parameters of the direct distribution network system, a current loop closed-loop transfer function and a voltage loop closed-loop transfer function are obtained respectively, and an open-loop transfer function and a closed-loop transfer function of a power loop are obtained in combination with the parameter setting value of the PI controller of the voltage loop. In a plurality of VSC converter stations, a master station and a slave station are arranged,