Active power filter for detecting harmonic wave and wattless current and detecting method thereof

Abstract

The invention discloses an active power filter for detecting a harmonic wave and a wattless current and a detecting method thereof. The active power filter comprises a harmonic wave and wattless current detecting circuit and a compensating current generating circuit, wherein the harmonic wave and wattless current detecting circuit and the compensating current generating circuit are successively connected in series at the current side of a power grid. The compensating current generating circuit comprises a current tracking control module, a driving circuit module and a main circuit module, wherein the current tracking control module, the driving circuit module and the main circuit module are successively connected in series. The topological structure of the main circuit module is a three-phase four-leg PWM converter. Compared with prior art, a novel harmonic wave detecting algorithm according to the invention does not require a phase-locked loop or matrix transform, thereby effectively prevent a zero-sequence harmonic leakage error caused by coordinate conversion, greatly improving detecting precision and greatly improving compensation effect.

Description

technical field [0001] The present invention relates to the field of electric power systems, and specifically refers to a harmonic current detection method applied in a three-phase four-wire active power filter to avoid zero-sequence harmonic leakage errors caused by coordinate transformation. Background technique [0002] In the past 30 years, with the wide application of power electronic devices in the industry, the problem of harmonic pollution in the power grid has become increasingly serious, seriously affecting power quality. Harmonics not only affect the normal operation of electrical equipment, but also bring hidden dangers to the safe and economical operation of the power grid. [0003] Since the principle of active power filter was proposed, the detection of harmonic current has caused extensive research and has developed a variety of methods. The detection methods of harmonic and reactive current generally include: analog filter detection method, FFT-based Detect...

AI Technical Summary

Problems solved by technology

[0004] The present invention is aimed at traditional p-q method and i p -i q Due to the problem of zero-sequence leakage error caused by coordinate transformation, a new improved harmonic current detection scheme for three-phase four-wire active power filters is proposed. This method does not require a phase-locked loop. No need for matrix transformation, effectively avoiding zero-sequence harmonic leakage error

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