SINGLE PHASE VOLTAGE DIGITAL PHASE LOCKING METHOD

The present invention relates to a single phase voltage digital phase locking method, and a preset level signal similar to a voltage signal to be measured is constructed. In the control process, according to an angular frequency obtained by the accumulation of an incremental angular frequency outputted by a PI controller and a reference angular frequency, a preset frequency is adjusted; the phase difference component of level vectors corresponding to two voltage signals is controlled to approach 0; and when the control is stable, the phase of the signal to be measured is tracked by an outputted phase angle, and a phase locking function is completed. According to the present invention, the current sampling point of the voltage signal to be measured and a previous (k-n)th sampling point are used to form level vectors. In the control process, only n sampling points are needed to be kept; when n is equal to 1, only the sampling values of one sampling period are needed to be kept. The storage space occupied is ver