Plug-and-play active electric power filtering device

Abstract

The invention discloses a plug-and-play active electric power filtering device and is applicable to a circuit comprising a system power source and a harmonic load. The plug-and-play active electric power filtering device comprises a mutual inductor, an inverter and a modulation signal generation module, wherein a winding at a primary of the mutual inductor is a power transmission wire penetrating between the system power source and the harmonic load of the internal portion of a core, the modulation signal generation module is used for generating a modulation signal of the inverter, the modulation signal is generated through superposing a primary fundamental current after reverse amplification and a primary harmonic current after positive amplification, and the inverter is used for converting a DC signal into an AC current signal same as the modulation signal in frequency and injecting the AC current signal to a secondary winding of the mutual inductor to make primary fundamental equivalent impedance of the mutual inductor be Z1+(1-alpha)Zm and make primary nth-order harmonic equivalent impedance of the mutual inductor be nZ1+(1+beta)nZm. The plug-and-play active electric power filtering device is advantaged in that the specially-produced mutual inductor is employed to make the active filtering device realize the plug-and-play function, the primary of the mutual inductor can be controlled for being in short circuit relative to a fundamental state and for being in an opening circuit relative to a harmonic state, and the filtering function is further realized.

Description

technical field [0001] The invention belongs to the technical field of active power filtering, and more specifically relates to a plug-and-play active power filtering device. Background technique [0002] As power electronic nonlinear loads are more and more widely used in industrial and civil fields, the current waveform distortion in the power grid is more serious, and the problems of harmonics and reactive power are becoming more and more significant. For harmonics and power factor problems, the industry has proposed a variety of solutions, the main filtering solutions include traditional passive LC filter, traditional parallel active power filter, series hybrid active power filter, injection hybrid Active power filter and unified power quality conditioner. [0003] Passive filters are large in size and weight, and can only filter out harmonics of specific frequencies; among all power filters, the series hybrid active power filter can greatly improve the harmonic impedan...

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Problems solved by technology

[0009] Aiming at the defects of the prior art, the purpose of the present invention is to solve the problem that the existing active power filter only compensates the fundamental magnetic flux on the one hand, thereby only reducing the equivalent impedance of the fundamental wave. When the transformer used is determined, its harmonic The equivalent impedance is a fixed value. In order to obtain a better filtering effect, a large-capacity transformer is required; on the other hand, the existing active power filter is connected to the power grid through a transformer. , the technical problem that the filter device cannot be directly connected to the grid or removed from the grid

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