Three-level three-phase four-wire active power filter and control method thereof

A power filter, three-phase four-wire technology, applied in active power filtering, harmonic reduction devices, AC networks to reduce harmonics/ripples, etc., can solve problems such as three-phase imbalance, improve performance, Effects of eliminating loss and reducing production cost

Inactive Publication Date: 2012-07-25
HUNAN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The technical problem to be solved by the present invention is to provide a three-level three-phase four-wire active power filter and its control method. The three-level three-phase four-wire active power filter and its control method effectively solve the problem of power distribution Three-phase Unbalanced Harmonic Filtering Problems in Network

Method used

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  • Three-level three-phase four-wire active power filter and control method thereof
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  • Three-level three-phase four-wire active power filter and control method thereof

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Embodiment 1

[0037] figure 1 It is a structural schematic diagram of a three-level three-phase four-wire active power filter, which consists of a double capacitor, a three-level inverter bridge, a pre-stage output filter, a post-stage output filter and a grid-connected switch. The grid-connected switch includes two parts: a start switch and a work switch. Its working process is as follows,

[0038] 1) The start switch is closed, the filter is powered on, and the dual capacitors are charged through the reverse diode of the inverter bridge. Since the start switch is connected in series with a resistor, the charging current is limited to protect the entire filter from being charged during power-on. Destroyed by excessive peak current;

[0039] 2) The sum U of the double capacitor voltage is detected DC (U DC =U DC1 +U DC2 ) reaches the rated value, the control work switch is closed, at this time, the start switch is bypassed, eliminating the loss caused by the series resistance. If it ...

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Abstract

The invention discloses a three-level three-phase four-wire active power filter and a control method thereof. The filter comprises two capacitors, a three-level inverter bridge, a previous LC (inductance and capacitance) output filter, a posterior LC output filter and a grid-connected switch, middle points of the two capacitors are directly connected with a neutral wire of a power grid, the two capacitors are connected with three bridge arms of the three-level inverter bridge in parallel after being serially connected with each other, the three-level inverter bridge is a three-level diode-clamped type three-level inverter bridge, and an output end of the three-level inverter bridge is connected into a three-phase power source in a three-phase four-wire power source by the previous LC output filter, the posterior LC output filter and the grid-connected switch sequentially. The control method includes controlling the three-level three-phase four-wire active power filter by the aid of control of three control loops and a hysteresis comparator.

Description

technical field [0001] The invention belongs to the active power filtering technology, and relates to a three-level three-phase four-wire active power filter and a control method thereof. Background technique [0002] With the improvement of living standards, household appliances are used more and more frequently, and there are more and more varieties. Many household appliances are powered by DC, which makes more and more rectifiers in the distribution network, resulting in harmonics in the distribution network. Wave pollution is getting worse. At present, in the design of building power distribution, the influence of harmonics is often not considered. When the harmonic content is too large, it will cause tripping and seriously affect people's daily life. [0003] The treatment of harmonics is mainly divided into passive power filtering and active power filtering. The former uses inductance and capacitance in series to form a harmonic path. By designing the inductance and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/01
CPCY02E40/40Y02E40/22Y02E40/20
Inventor 荣飞罗安周贤正谢三军朱文杰
Owner HUNAN UNIV
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