Measuring method of electric parameters with wide change range and system

Abstract

The invention provides a measuring method of electric parameters with a wide change range and system. The method is applied to a microgrid where medium-small capacity wind generating sets are accessed. The method includes the steps of step 1, obtaining discrete voltage signals through discrete sampling on instantaneous voltage signals, carrying out sliding-window iterative discrete Fourier transform, combined with phase lock negative feedback phase angle signals, on the discrete voltage signals so as to obtain phase difference signals, step 2, carrying out proportional integral control on the phase difference signals to obtain fundamental wave angle frequency of zero phase difference signals, step 3, obtaining output frequency through the fundamental wave angle frequency, carrying out discrete integration on the output frequency and adding the output frequency and the fundamental wave angle frequency to obtain a phase angle, and carrying out phase locking negative feedback on the phase angle, and step 4, computing to obtain voltage and current effective values through the output frequency. The method achieves the purpose of digital phase locking of voltage wide in frequency change range, and provides an input parameter measuring method for quick power control of the medium-small capacity wind generating sets.

Description

technical field [0001] The invention relates to the technical field of renewable energy power generation, in particular to a method and system for measuring electrical parameters applicable to a wide range of changes in microgrids. Background technique [0002] A microgrid is a microgrid, which refers to a small power generation and distribution system composed of distributed power sources, energy storage devices, energy conversion devices, related loads, and monitoring and protection devices. An important trend in the development of power grids in the future. With the decrease of conventional energy sources, wind power is playing an increasingly important role in the smart grid. However, wind power cannot achieve stable operation through input power and generator excitation control like conventional power sources. Generally, large-scale grid-connected wind turbines can achieve the first level of AC and DC power control by adding a coaxial pulse encoder phase-locked and the...

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Problems solved by technology

[0004] The present invention solves the problems of wide frequency variation range, poor dynamic performance and slow d...

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