Quadrature signal generating method based on sliding mode observer and quadrature signal generator

Abstract

The invention relates to the technical field of devices where two or more generators, converters and transformers are used for parallel feed for a network and discloses a quadrature signal generatingmethod based on a sliding mode observer and a quadrature signal generator. The quadrature signal generating method based on the sliding mode observer uses an integrator for acquired single-phase voltage signals, and constructs a mathematical model of the voltage signals and integral quantities thereof. A sliding mode observer based on the mathematical model is constructed, and the single-phase voltage signals and quadrature signals thereof are obtained. The method can obtain the virtual quadrature signals through the designed sliding mode observer, and can effectively suppress different kindsof power grid disturbances including harmonics, noise signals, DC flow rate and the like. Compared with SOGI-QSG, SMO-QSG has better response speed and smaller steady-state error under the condition of frequency hopping, the condition that the power grid has 5 times and 7 times harmonics and the condition of adding a definite value of direct currents and containing noise signal.

Description

technical field [0001] The present invention belongs to the technical field of a device for feeding power in parallel to a network by two or more generators, converters or transformers, and in particular relates to a method for generating an orthogonal signal based on a sliding mode observer and an orthogonal signal generator . Background technique [0002] At present, the commonly used prior art in the industry is as follows: In the application field of single-phase phase-locked loop (PLL), quadrature signal generators (QSGs) are often used to generate virtual quadrature signals for single-phase power grids. The quadrature signal generator can generate two sinusoidal signals with a phase difference of π / 2, and use the two generated sinusoidal signals for quadrature modulation and quadrature demodulation. Common QSGs methods in the prior art include: T / 4-based delay QSG (TD-QSG) method, inverse park-based QSG method (IPT-QSG), and second-order generalized integrator-based Q...

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Problems solved by technology

[0005] (2) The QSG method based on the second-order generalized integrator is difficult to filter out the signal noise in the power grid. When there is a DC component in the power grid, the accuracy of its estimation will become worse and it is difficult to improve the dynamic response speed

[0007] Through the above analysis, it can be seen that the above method cannot simultaneously suppress different types of grid disturbances including harmonics, noise signals, DC flow, etc., and generate accurate virtual orthogonal signals

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