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Method and system for feedback type active power filtering of output current with DC sourse

A technology of output current and power filtering, which can reduce harmonics/ripples and other directions when applied to DC circuits, and can solve problems such as increasing the difficulty of system compensation processing, unstable filtering processing, and reducing ripple suppression effects

Inactive Publication Date: 2003-10-29
TSINGHUA UNIV
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Problems solved by technology

This increases the difficulty of system compensation processing, easily causes control oscillation, and also reduces the effect of ripple suppression
The design of comb filter or slot filter in the existing active power filter method is also difficult. In principle, the transfer function F of filter processing a The poles of (s) are closer to ±j2πf i Then for frequency f i The better the ripple suppression effect, but this will inevitably make the filtering process unstable
At the same time, this will also make the intermediate signal i r and reference wave signal u a If it is too large, if it exceeds the allowable range of the pulse width modulation input, the control system will not be stable, and the effect of suppressing the ripple cannot be achieved.

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  • Method and system for feedback type active power filtering of output current with DC sourse
  • Method and system for feedback type active power filtering of output current with DC sourse
  • Method and system for feedback type active power filtering of output current with DC sourse

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Embodiment Construction

[0033] A specific embodiment of the present invention is designed to reduce the low-frequency ripple noise loaded on the transmission line by the rectifier circuit of a 500 kV DC transmission system. The circuit rectified from AC to DC is such as Figure 6 As shown, the three-phase AC bus frequency is 50Hz and the line voltage is 382.9 kV; the transformation ratio of the star / delta type transformer T1 and the star / star type transformer T2 are both 345.0 dry volts: 213.5 kV, and the rated capacity is 603.7 Megavolt-ampere, the standard per unit value of short-circuit impedance is 0.18; a 12-pulse rectifier circuit is realized by using a rectifier bridge composed of 12 thyristors, the conduction control angle is 5 degrees, and the output DC voltage is about 500 kV. The voltage generated by the rectifier circuit and input to the active power filter system of the present invention mainly contains low-frequency ripples of 600, 1200, 1800, and 2400 Hz.

[0034] The output load of the em...

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Abstract

An output current feedback type active electric power filtering method with DC source is characterized by that the serially connected equivalent impedance has positive resistance characteristics and the gain coefficient is used to control the value of equivalent impedance, so decreasing the ripple voltage and ripple current of output. Its system is characterized by that a current transformer is mounted to output of said filter, and the detected current signal passes through band-pass filter, gain amplifier, PWM and pulse driver to control the single-phase voltage inverter, whose output voltage pulse passes through coupling transformer, smoothing reactor and passive filter to suppress the ripples.

Description

Technical field: [0001] The invention relates to an output current feedback type active power filtering method and system with a direct current source. The method and system can suppress and eliminate the low frequency ripple of an input direct voltage signal, and reduce the low frequency ripple of an output load. Wave voltage and current noise. The invention belongs to the technical field of direct current transmission. Background technique: [0002] The DC transmission voltage or DC power supply voltage obtained by rectifying the AC signal contains a large amount of low-frequency ripple noise. These ripple noises will increase the burden on the equipment on the DC transmission lines of the power system, resulting in power loss, and its electromagnetic radiation will also interfere with communication equipment. The ripple noise in the DC power supply will interfere with the useful signal in the load equipment and seriously affect the normal operation of the equipment. The tradit...

Claims

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Application Information

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IPC IPC(8): H02J1/02
Inventor 庞浩王赞基张海波
Owner TSINGHUA UNIV
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