Harmonic generator and control method based on recursive discrete Fourier transform

Abstract

The invention discloses a harmonic generation device and a control method based on a recursive discrete Fourier transform. The harmonic generation device based on the recursive discrete Fourier transform comprises a fundamental wave realization module, a harmonic generation module, a three-phase series-coupled transformer group and a three-phase load. The harmonic generation module extracts the amplitude of the harmonic voltage on the load side of the power network simulator efficiently through the recursive discrete Fourier transform, outputs a given reference value of the amplitude closed-loop control of the harmonic voltage, and thereby performs the harmonic amplitude closed-loop control. The invention discloses a harmonic generation device and a control method based on the recursive discrete Fourier transform, which not only ensures the harmonic generation precision of a power network simulator, but also improves the dynamic performance of the power network simulator, and better meets the test requirements of modern electric and power electronic equipment.

Description

technical field [0001] The invention belongs to the field of power quality analysis and control, in particular to a harmonic generation device and control method based on recursive discrete Fourier transform. Background technique [0002] Since the 20th century, with the rapid development of human science and technology, huge non-renewable fossil energy has been consumed continuously, and the fossil energy will eventually be exhausted in the near future. At present, developed countries and regions such as the United States, the European Union, and Japan have placed new energy power generation technology in a very important position in the process of energy structure adjustment. [0003] The grid-connected operation of the new energy power generation system can reduce energy consumption, save investment, improve the reliability and flexibility of the power system, and is an important direction for the development of the power industry in the 21st century. In recent years, wi...

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Problems solved by technology

[0005] The Chinese invention patent (publication number CN 105116794 A) published on December 2, 2015 "Grid Simulator Control Method Suitable for Small and Medium-Capacity Distributed Power Access", the invention can simulate a variety of grid faults, and the highest switch of the inverter link The frequency is adjustable, suitable for small and medium-capacity distributed power access testing, but this invention only provides the implementation steps of the grid simulator function, and has not done in-depth research on the specific grid fault control method;

[0006] Chinese invention patent (publication number CN 106487240 A) published on March 8, 2017 "A Power Grid Simulator with Accurate Harmonic Voltage and Virtual Impedance Control", the invention provides a The grid simulator of impedance control can not only simulate standard grid output voltage, grid voltage fault conditions and grid harmonic content, but also simulate grid impedance changes, but the present invention has the following disadvantages: the invention adopts fast Fourier transform (FFT ) to analyze the load current, the amount of calculation is large and the dynamic performance is poor. At the same time, the harmonic generation adopts the control method of PI+repetitive control, which makes it difficult to set the PI parameters and has poor flexibility;

[0009] 1. There is little research on the influence of harmonic extraction methods on the dynamic performance of power grid simulators. In order to better meet the test requirements of modern electrical and power electronic equipment, it is necessary to conduct research on the dynamic performance of power grid simulators to improve and perfect power grid simulation device function;

[0010] 2. The harmonic voltage control method in the grid simulator is not efficient enough, and its flexibility and speed are also poor. These problems need to be improved

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