Abstract: Dynamic voltage restorer（DVR） is a device to effectively control the voltage dip fault at the device side. At present, the control design of DVR basically uses proportional-integral（PI） controller, but it is a nonlinear system, and the traditional PI controller can not achieve the ideal control effect. In order to improve the control effect of DVR, a novel voltage-current double closed loop fractional order PI（FOPI） control strategy is proposed in this paper. Firstly, the photovoltaic energy storage system is taken as the DC energy source of DVR, and the corresponding mathematical model of feedforward decoupling of three-phase inverter is established. Secondly, the double closed-loop PI control strategy of photovoltaic energy storage system and inverter is designed, and the parameters are adjusted. Then the integer order control strategy is extended to fractional order to improve the control effect, and the robustness criterion is used to correct the parameters of FOPI controller when the gain changes. Finally, DVR simulation models under different control strategies are built, and the simulation results verify the feasibility of FOPI controller applied to DVR system, and it has better dynamic response speed and anti-interference performance than traditional PI controller.