Phase-locked loop and method for measuring voltage phase and frequency

The invention discloses a phase-locked loop and a method for measuring voltage phase and frequency. The phase-locked loop comprises a signal detecting device, a strong filter, an equivalent signal frequency computing device, an equivalent signal phase acquiring device and a phase compensating device; and the signal detecting device, the strong filter, the equivalent signal frequency computing device, the equivalent signal phase acquiring device and the phase compensating device are sequentially connected with one another, and an output end of the phase compensating device is connected with the signal detecting device, so that an annular detecting system is formed. The method for detecting the voltage phase and the frequency includes computing the frequency of equivalent signals after the signals inputted into the phase-locked loop are filtered and processed; and acquiring the phase of the inputted signals on the basis of the frequency by means of counting, phase compensating and the like. The phase-locked loo