A plug-and-play active power filter device for specified sub-harmonics

Abstract

The invention discloses a plug-and-play specified subharmonic active electric power filtering device. The 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 winding has one loop, the core of the mutual inductor is a fine long cylindrical structure or is a fine long cuboid structure suitable for a busbar, 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 specified subharmonic 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 specified subharmonic equivalent impedance of the mutual inductor be nZ1+(1+beta)nZm. The device is advantaged in that the plug-and-play function is realized through the mutual inductor, for specified subharmonic compensation, capacity and cost of the whole set device are reduced.

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 for specified harmonics. 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 impr...

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Problems solved by technology

[0010] 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 adopts the full current compensation method on the one hand, which greatly reduces the system stability, and due to the increase of the capacity of the transformer and each switching device of the system, the Increased cost; on the other hand, the existing active power filter is connected to the grid through a transformer. When the system is working normally, it cannot be directly connected to the grid or disconnected from the grid without disconnecting the line.

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