Composite control method and system for voltage sag detection of dynamic voltage restorer

The invention belongs to the technical field of voltage detection control, and particularly relates to a composite control method and system for voltage sag detection of a dynamic voltage restorer, and the method comprises the steps: obtaining a single-phase reference voltage of the dynamic voltage restorer; determining a three-phase voltage instantaneous value according to the real-time three-phase voltage and the single-phase reference voltage of the dynamic voltage restorer; constructing a three-phase circuit of the dynamic voltage restorer according to a time-delay phase shift method and the single-phase voltage of the dynamic voltage restorer, and respectively determining single-phase virtual three-phase voltage; and according to the determined three-phase voltage instantaneous value and the single-phase virtual three-phase voltage, an action instruction of the dynamic voltage restorer is controlled, and composite control of voltage sag detection of the dynamic voltage restorer is completed. According to