Method and system for predicting ultra-high-order harmonics generated by pulse width modulation

Abstract

The invention discloses a method and a system for predicting ultra-high-order harmonics generated by pulse width modulation. The method comprises the following steps of: acquiring a sampling mode of the pulse width modulation, a topological structure of pulse width modulation equipment and waveforms of modulated waves and carrier waves; deducing a dual Fourier transform formula in a modulation converter system by using a Fourier transform basic theory; calculating undetermined parameters in the deduced dual Fourier transform by using the waveforms of the modulated waves and the carrier waves, and calculating coefficients of sampling under different rules; and obtaining a mathematical model of an ultra-high harmonic generation result under a corresponding application scene and the sampling mode by using the calculated coefficients of the sampling under different rules, determining the amplitude of the ultra-high harmonics under the corresponding frequency according to the coefficients of the sampling under different rules, and processing the ultra-high harmonics with the amplitude higher than 0.05 pu to realize ultra-high harmonic prediction. According to the method and system, theoretical and method bases are provided for pulse width modulation mode design, ripple filter design, ultra-high harmonic influence evaluation and the like developed for reducing ultra-high harmonics, and the electric energy quality of a power grid system rich in a power electronic grid-connected converter can be improved.

Description

technical field [0001] The invention belongs to the technical field of power electronics technology and power grid power quality, and in particular relates to a method and system for predicting ultra-high harmonics generated by pulse width modulation. Background technique [0002] Thanks to the high flexibility and high controllability of power electronic equipment in the field of power conversion, it has been more and more widely used in all aspects of the power system. Especially in terms of the utilization of renewable energy, the integration of energy storage systems, the promotion of smart grids, and the improvement of the intelligent level of user loads, power electronics have shown significant performance advantages over traditional power equipment. Among the many challenges of power electronic distribution network, the problem of ultra-high harmonics introduced by high-frequency switching characteristics of power electronic equipment is a more prominent one. [0003...

AI Technical Summary

Problems solved by technology

With the continuous development of power semiconductor technology, new power electronic devices such as insulated gate bipolar transistors (IGBTs) and MOSFETs that can realize self-commutation technology have appeared, and their switching frequencies are as high as several thousand to tens of kilohertz. The application of gallium oxide devices, whose frequency band can reach hundreds of kilohertz or even megahertz, the ultra-high harmonics brought by these switching frequencies will not only reduce the power quality, but also induce secondary effects by coupling that will endanger the operating performance of power equipment and reduce the Reliability of grid operation

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