Active harmonic management device

Abstract

The invention discloses an active harmonic management device. The device comprises an instruction current operational circuit and a compensating current generation circuit. The instruction current operational circuit is used for detecting harmonic wave and reactive power current components in compensating load currents, and the compensating current generation circuit is used for generating actual compensating currents according to an instruction signal of the compensating currents, wherein the instruction signal is obtained according to the instruction current operational circuit. The compensating current generation circuit comprises a main circuit, a driving circuit and a current tracking and controlling circuit. The active harmonic management device has the advantages that dynamic compensation is achieved, harmonic waves changeable in frequency and size and changeable reactive power can be compensated, and response to changes of a compensated object is rapid; the harmonic waves and the reactive power can be compensated at the same time, and the intensity of the compensated reactive power can be continuously adjusted; influences caused by power grid impedance are small, and harmonic vibration between the active harmonic management device and the power grid impedance is not prone to occurring; changes of power grid frequencies can be tracked, so that the compensating performance is not affected by the changes of the power grid frequencies.

Description

technical field [0001] The invention relates to the technical field of electrical products, in particular to an active harmonic controller. Background technique [0002] With the wide application of power electronic devices, a large number of harmonics are injected into the grid, resulting in the deterioration of the power quality of the entire grid. The harm of harmonic current in the power grid is mainly reflected in the following aspects: [0003] Harmonics cause additional harmonic loss to the equipment in the power grid, reduce the efficiency of the power grid, power transmission and power consumption equipment, and increase the line loss of the power grid. [0004] Harmonics will generate additional thermal effects, which will cause heating of electrical equipment, aging its insulation and reducing the service life of the equipment. In an independent small power grid, harmonic currents will also cause additional loss and heat generation in transformers and generators...

AI Technical Summary

Problems solved by technology

In an independent small power grid, harmonic currents will also cause additional loss and heat generation in transformers and generators, causing mechanical vibration and noise, greatly increasing heat loss in electrical equipment, accelerating insulation aging, and affecting equipment life; The skin effect causes the surface of the stator and rotor to be overheated and damaged

[0005] Harmonics can easily cause resonance between the power grid and the compensation capacitor, amplifying the harmonic current several times or even dozens of times, which not only directly damages the capacitor, but also aggravates the threat to other electrical equipment

This is especially obvious in independent small grids, because the grid voltage frequency fluctuation range is relatively large, which is more likely to cause resonance

[0006] Harmonics will cause some protective equipment to malfunction, such as relays, fuses, etc., and will also cause inaccurate measurement of electrical measuring instruments

In the oil field independent power grid, the measurement error caused by harmonics to the mud logging instrument may affect the normal operation of the entire oil field

[0007] Harmonics will interfere with the nearby communication system. The light ones will introduce noise and reduce the quality of the call. The severe ones will cause signal loss and make the communication system unable to work normally.

[0008] The main harmonic devices currently on the market have the following disadvantages: the resonant frequency of the single-tuned filter will change due to the deviation or change of the capacitance and inductance parameters, and the frequency of the grid will fluctuate to a certain extent, which will cause the filter to detune, and the change of the grid impedance will affect the single The filtering effect of the tuned filter has a great influence, and what is more serious is that the grid impedance and the filtering device may have parallel resonance

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