Single-phase phase-locked loop

The invention discloses a single-phase phase-locked loop. The single-phase phase-locked loop comprises a phase discriminator, a loop filter and a voltage-controlled oscillator, wherein the phase discriminator comprises a Clark transformation part, a positive sequence transformation part and a Park transformation part, a voltage input signal and two zero signals are sent to the Clark transformation, an output signal of the Clark transformation and the output angular frequency of the phase-locked loop are sent to an input end of the sequence transformation together, an output signal of the positive sequence transformation and an output phase of the phase-locked loop are sent to the Park transformation together, and an output signal of the Park transformation is an output signal of the phase discriminator; and an output end of the phase discriminator is connected with an input end of the loop filter, and the output signal of the loop filter is sent to an input end of the voltage-controlled oscillator after being added with an initial value. The phase-locked loop having the advantages of simple algorithm, low cost and high phase locking accuracy, not only can accurately track the phase and the amplitude of a power grid when the phase of the power grid varies, but also can rapidly and accurately track the phase of the power grid when the frequency of the power grid varies.