Single-phase adaptive frequency-locking system for reducing harmonic influence of power grid

Abstract

The invention relates to a new energy generating grid-connected system, and provides a single-phase adaptive frequency-locking system capable of improving the stability of a frequency adaptive system. The system is advantaged by fast response speed, small operation amount, and high robustness, and is applicable to a power grid synchronization system with severe distortion of the power grid voltage. According to the technical scheme of the single-phase adaptive frequency-locking system for reducing the harmonic influence of the power grid, two orthogonal signal generators are cascaded to generate two groups of orthogonal signals, and a frequency adaptive controller constructs the frequency adaptive system through combined operation of the two groups of orthogonal signals. The system is mainly applied to new energy generating grid-connected occasions.

Description

technical field [0001] The invention relates to a new energy power generation grid-connected system, in particular to a novel single-phase grid synchronization technology capable of reducing the influence of grid harmonics. Specifically, it involves a single-phase adaptive frequency-locking system that reduces the influence of grid harmonics. Background technique [0002] With the continuous development of the smart grid, more and more clean energy sources such as solar energy and wind energy generate electricity in a reliable way. The integration of distributed power sources with the environment and flexible power generation methods have brought great changes to the contemporary power system. In order to ensure that distributed power supplies provide reliable power to the grid, a grid-connected control strategy with superior performance is an essential link. In the concrete implementation of the grid-connected control strategy, it becomes a key basic problem to accurately...

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Problems solved by technology

Among them, although the phase-locked loop method based on synchronous rotating coordinate transformation can accurately capture the frequency and phase of the fundamental component of the input voltage, this method is not suitable for single-phase systems; Only two zero-crossing points can be detected, and when the grid voltage waveform is severely distorted, the voltage zero-crossing point will usually drift, so this method will significantly reduce the output accuracy and response speed of the phase-locked loop; instantaneous reactive power control phase-locked The method obtains the phase information of the grid by constructing the sine quantity of the grid voltage and then performing an orthogonal transformation

The traditional single-phase phase-locked loop based on the theory of instantaneous reactive power is improved on the basis of the three-phase phase-locked loop, and its algorithm itself has a slow response speed

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