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Active power filtering method with inversing capacitor regulation and branch impendance controlled decoupling

A branch reactance and capacitance adjustment technology, applied in the field of reactance value, can solve the problems affecting the ripple suppression effect and the ripple phase shift of the frequency band of concern

Inactive Publication Date: 2003-11-19
TSINGHUA UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In the digital implementation of this existing active power filter control method, there is a delay that is difficult to compensate in the process of measurement sampling, algorithm calculation, and pulse width modulation, which will cause a large phase shift to the ripple in the frequency band of interest. And seriously affect the effect of ripple suppression

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  • Active power filtering method with inversing capacitor regulation and branch impendance controlled decoupling
  • Active power filtering method with inversing capacitor regulation and branch impendance controlled decoupling
  • Active power filtering method with inversing capacitor regulation and branch impendance controlled decoupling

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Embodiment Construction

[0087] 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 in the 500 kV direct current transmission system. A circuit that converts alternating current to direct current is Figure 7 As shown, the frequency of the three-phase AC bus is 50 Hz, and the line voltage is 382.9 kV; the transformation ratios of star / delta type transformer T1 and star / star type transformer T2 are both 345.0 kV: 213.5 kV, rated capacity 603.7 MVA, the unit value of the short-circuit impedance is 0.18; a rectifier bridge T composed of 12 thyristors is used to realize a 12-pulse rectification circuit, the conduction control angle is 5 degrees, and the output DC voltage is about 500 kV. The voltage generated by the rectification circuit mainly contains low-frequency ripples of 600, 1200, 1800 and 2400 Hz, and the voltage will be input into the active power filter system of the present invention.

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Abstract

First, the decoupling controlled by frequency domain is realized by using a group of band-pass filtering. Next, the resistance in the filtering branch circuit is negative feedback controlled in order to adjust voltage of the inversion capacitance making it keep at setting value of voltage. Then, the method of parameter adaptation is utilized to make the reactance at concerned ripple frequency point of the filtering branch circuit become zero so as to restrain ripple. Finally, the decoupling of resistances and reactances in filtering branches including two phase-shift filtering circuits with 90-degree phase shift is controlled so as to obtain the reference wave for pulse-duration modulation. The invented method is no need of DC power source. The invention solves phase-shift problem caused in each step in controlling procedure.

Description

Technical field: [0001] The invention relates to an active power filter method for adjusting inverter capacitors and branch reactance control decoupling. The method can maintain the working voltage of inverter capacitors on the DC side of a single-phase voltage type inverter circuit to replace DC power supplies. , and can control the reactance of the filter branch at the same time, and suppress and eliminate low-frequency ripple noise by making the reactance value of the filter branch in the concerned ripple frequency band zero. The invention belongs to the technical field of direct current power supply. Background technique: [0002] The DC transmission voltage or the 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 equipment burden on the DC transmission line of the power system, resulting in power loss, and its electromagnetic radiation will also interfere with commun...

Claims

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Application Information

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IPC IPC(8): H02J1/02H02M1/14
Inventor 庞浩王赞基
Owner TSINGHUA UNIV