Low pass filter, active power filtering device and harmonic detection method

Abstract

The invention discloses a low pass filter, an active power filtering device and a harmonic detection method based on the active power filtering device.. The low pass filter is formed by an IIR (infinite impulse response) filter and an MA (moving average) filter in a cascade manner. The active power filtering device comprises a main circuit, a mutual inductance regulating circuit, an AD (analog-to-digital) sampling circuit, a detection circuit and a control circuit, wherein the main circuit is used for injecting compensation current to a three-phase power grid, the detection circuit utilizes the low pass filter, and the control circuit is used for forming a driving signal of the main circuit. Through utilizing the active power filtering device, the harmonic detection method disclosed by the invention comprises the following steps of: sequentially detecting, regulating and carrying out AD sampling on load current of the three-phase power grid; extracting harmonic current; and forming a driving signal according to the harmonic current. The invention prevents a problem that the separation of direct current amount and alternating current amount of active current and reactive current is poor in the traditional harmonic detection technique, improves the filtering precision, has quick dynamic response and can quickly and exactly detect the content of the harmonic current in the power grid.

Description

technical field [0001] The invention relates to the technical field of power electronic control, in particular to a low-pass filter, an active power filter device and a harmonic detection method based on the active power filter device. Background technique [0002] With the development of power electronic technology, power electronic equipment has become the main harmonic source in the power system. Harmonics will reduce the efficiency of production, transmission and utilization of electric energy, and bring serious danger to the normal operation of power supply and consumption equipment. Therefore, harmonic control has received more and more attention. [0003] Commonly used harmonic control methods include passive filters and active power filters (active power filter, APF). With the development of high-power electronic devices, the advantages of active power filters are becoming more and more obvious. [0004] The general operating principle of the active power filter in...

AI Technical Summary

Problems solved by technology

[0013] The invention provides a low-pass filter, an active power filter device using the low-pass filter and a harmonic detection method based on the active power filter device, which overcomes the problems of the active power filter device in the prior art. The problem of poor separation of the DC and AC quantities of active current and reactive current during harmonic detection improves the filtering accuracy and has a faster dynamic response, so that the harmonic current content in the power grid can be quickly and accurately detected

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