Phase difference measurement method and device based on instantaneous reactive power

The invention provides a phase difference measurement method and a device based on instantaneous reactive power. The method comprises the following steps: 1, acquiring a first instantaneous current value when the phase is phi and a second instantaneous current value when the phase is zero at any t moment; 2, respectively converting the first instantaneous current value and the second instantaneouscurrent value into two trigonometric function periodic signals, wherein the two trigonometric function periodic signals are same-frequency signals; 3, constructing a first measurement matrix and a second measurement matrix according to the two trigonometric function periodic signals; and 4, calculating to obtain a phase value according to the first measurement matrix and the second measurement matrix. The device comprises an acquisition unit, a conversion unit, a matrix construction unit and a calculation unit, the phase difference can be calculated by constructing a matrix according to the selected instantaneous cur