In order to realize the LVRT of the PV power system by using supercapacitor energy storage during the grid voltage drop, the active power reference of the DPC according to the grid voltage sags are given, at the same time by controlling the bidirectional DC/DC converter with voltage and current dual loop, the DC side of excess energy stores in supercapacitors, in order to balance the power on both sides of the inverter and to maintain the DC bus voltage. The proposed scheme is proved to be feasible and effective in MATLAB/Simulink.