Three-phase active power filter harmonic current detection method based on FBD method

Abstract

The invention discloses a three-phase active power filter harmonic current detection method based on an FBD method. The FBD method is correspondingly deduced and thoroughly researched, and the three-phase three-wire system current detection method based on FBD fundamental wave active currents, fundamental wave reactive currents, harmonic currents, fundamental wave negative-sequence currents and any subharmonic currents is put forward. The method essentially means projection transformation, the detection result is decided by reference voltages, a detected current is always identical with the reference voltages in waveform and phase, different reference voltages are generated according to needs so that different current components can be detected, and the application range and field of the FBD method are greatly widened; meanwhile, the FBD method is very visual, 3 / 2 conversion is not needed, the algorithm is simple, the calculated quantity is small, and the FBD method can be applied to a three-phase system and a non-three-phase system as well. The simulation result proves correctness and feasibility of the proposed harmonic current detection method, and the harmonic current detection method can be used for compensation and control of harmonic waves and reactive power of APFs.

Description

technical field [0001] The invention belongs to the technical field of power detection, in particular to a method for detecting harmonic currents of three-phase active power filters based on the FBD method. Background technique [0002] In recent years, due to the large number of non-linear loads (such as rectifiers, frequency converters, etc.) put into use, the power quality at the user side has become increasingly serious, among which harmonic pollution is the main one. With the advancement of smart grid construction, various distributed power sources (such as small photovoltaic / photothermal power generation, small wind power generation), energy storage equipment (such as lithium battery packs, lead-acid battery packs, etc.) and electric vehicle charging stations have begun to appear. When these devices are connected to the grid, they also bring certain harmonic effects to the grid. [0003] Because grid harmonics are affected by factors such as randomness, distribution a...

AI Technical Summary

Problems solved by technology

The detection error of the analog filter method is large, especially when the grid frequency changes; it is sensitive to the parameters of circuit components; it cannot separate the reactive and active components of the fundamental current

[0004] In the early 1980s, the three-phase instantaneous reactive power theory proposed by Japanese scholar H.Akagi and others can be regarded as a special case of the FBD method, but it includes Park transformation, d_q transformation and its inverse transformation, and the algorithm is still relatively complicated. make it limited in application

DFR and adaptive detection method, long calculation delay, difficult to achieve real-time control

Fryze power is defined in the theory of average power. The traditional method of average power is obtained by integrating a period of data, which will bring a large delay to the detection of instantaneous reactive current, which cannot be used in occasions with high real-time requirements. Meet the requirements, not suitable for occasions where the load changes frequently, and can only detect harmonics and reactive currents at the same time, not only harmonics or reactive currents

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