Single-phase phase-locked loop method applied to low-voltage treatment equipment

The invention discloses a single-phase phase-locked loop method applied to low-voltage treatment equipment, and the implementation process of the method comprises the steps: collecting a signal value usk at the current sampling moment, a signal value usk1 at the previous sampling moment and signal values usk2 at the previous two sampling moments of a grid-connected point signal of the equipment through a voltage sensor, and enabling the sampling period to be Ts; taking the voltage signal obtained in the step 1 as an input signal of a first-stage second-order generalized integrator S1 to obtain an output signal qv1k at a sampling moment k; serving the orthogonal signal qv1k obtained in the step 2 as an input signal of an enhanced second-order integrator S2, and obtaining orthogonal fundamental wave signals qvk and vk at the sampling moment k in the qv1k; and performing mathematical transformation on the qvk and the vk to obtain the amplitude and the real-time phase of the fundamental wave. According to the inv