SINGLE-PHASE PHASE-LOCKED LOOP BASED ON ALL-PASS FILTER AND PHASE-LOCKING METHOD

摘要

A single-phase phase-locked loop based on an all-pass filter and a phase-locking method. The single-phase phase-locked loop comprises: an all-pass filter (102), configured to receive an input grid voltage signal U_i and a frequency signal Omiga, and to determine, according to the grid voltage signal U_i and the frequency signal Omiga, a first sinusoidal signal Ualfa and a second sinusoidal signal Ubata output at an output end; a phase detector (104) connected to the output end of the all-pass filter, and configured to determine, according to the first sinusoidal signal Ualfa and the second sinusoidal signal Ubata output by the all-pass filter, and a predefined reference signal, a phase difference between the grid voltage signal U_i and the reference signal, and to determine, according to the phase difference, a phase adjustment parameter Theta output at the output end; and a proportional integral controller (106) having an input end connected to the phase detector and an output end connected to the all-pass filter, configured to determine, according to the phase adjustment parameter Theta output by the phase detector, a frequency signal Omiga output at an output end, and to output the frequency signal Omiga to an input end of the all-pass filter. The algorithm of the single-phase phase-locked loop and the phase-locking method is simple to implement, and a sinusoidal signal of varying frequency can be tracked in real time.