Phase-locked loop and phase locking method of grid voltage phase measurement in grid-connection

Abstract

The invention discloses a phase-locked loop and phase locking method of grid voltage phase measurement in grid-connection. The phase-locked loop comprises a synchronizing transformer sampling circuit,a phase compensation circuit, a signal amplification circuit and a comparison output circuit, wherein the synchronizing transformer sampling circuit is used to sample phase signal, the phase compensation circuit is connected with a synchronizing transformer and used to delay compensation phase signal, the signal amplification circuit is connected with the phase compensation circuit and used to magnify signal and the comparison output circuit is connected with the signal amplification circuit and used for rising edge when phase is zero and failing edge when phase is 180 degrees. The method ofthe invention comprises the following steps: sampling phase signal, delaying compensation phase signal, magnifying signal and outputting the rising edge when phase passes through zero and the failingedge when phase is 180 degrees. The beneficial effect of the invention is that the synchronizing transformer and simulated transmittal circuit are adopted to form the phase-locked loop so as to avoidcomplicated voltage sampling conditioning circuit, cancel analog-to-digital conversion circuit, and realize simple circuit structure, high stability and low cost.

Description

technical field [0001] The invention relates to an electric power system, in particular to a phase-locked loop circuit and a phase-locking method for grid voltage phase detection in power generation and grid connection in the power system. Background technique [0002] In the wind power grid-connected system, in order to ensure that the grid-connected current and the grid voltage are strictly in the same frequency and phase, the phase-locked loop technology must be used. [0003] At present, most of them adopt the method of software phase-locked loop. The realization of the software phase-locked loop must first detect the grid voltage and the grid-connected current, use the precise hardware conditioning circuit and the analog / digital (A / D) conversion circuit to sample the voltage and current, and then use the signal processor to analyze the obtained The current and voltage sampling data are processed, and the tracking of the grid voltage phase is realized through the softwa...

AI Technical Summary

Problems solved by technology

[0005] The invention provides a phase-locked loop and a phase-locked method for grid voltage phase detection in grid-connected power generation, which are used to solve the problems of high cost and high complexity of software and hardware in the prior art

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