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Cascaded unified electric energy quality regulating system

A power quality adjustment and cascading technology, which is applied in the direction of AC network voltage adjustment, electrical components, circuit devices, etc., can solve problems that affect the reliability of joint operation, increase governance costs, and uneconomical problems, and achieve resonance problems and land occupation. And the effect of less loss, reducing loss and floor space

Active Publication Date: 2015-03-11
CSR ZHUZHOU ELECTRIC LOCOMOTIVE RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At this time, if one type of regulating device is used for each power quality problem, multiple devices will be used at the same time, which will greatly increase the treatment cost and increase the complexity of device operation and maintenance. There is also a problem of coordination and coordination between them, which affects the reliability of joint operation, so it is neither economical nor realistic. If there is a device that can solve multiple power quality problems at the same time, the above problems can be solved

Method used

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  • Cascaded unified electric energy quality regulating system
  • Cascaded unified electric energy quality regulating system
  • Cascaded unified electric energy quality regulating system

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Embodiment 1: as figure 1 As shown, this example is a single-phase unified power quality conditioner. The cascaded unified power quality regulation system of the present invention includes:

[0038] The cascaded parallel unit 1 is formed by cascading m*n H-bridge modules, connected to the grid through the connection reactance Ls, and exchanges active power, reactive power and harmonic power with the grid. The cascaded parallel unit 1 on the grid side adopts the mode based on H-bridge cascading. The switching frequency of a single switching device is relatively low, but the equivalent switching frequency after cascading is as high as tens of kilohertz, which can effectively compensate for harmonics. That is, after cascading, the equivalent switching frequency is very high, and it has a harmonic compensation function, which can effectively control the current harmonics of the power grid. Through the rectification control of the fundamental wave, it is possible to take p...

Embodiment 2

[0045] Implementation 2: If figure 2 As shown, this example is a three-phase delta-connected unified power quality conditioner. The structure and principle of this embodiment are basically the same as those of Embodiment 1. The reactive power control of each phase of the parallel cascade part can realize the compensation for voltage unbalance and control the negative sequence current.

Embodiment 3

[0046] Embodiment 3: as image 3 As shown, this example is a three-phase star-connected unified power quality conditioner. The structure and principle of this embodiment are basically the same as those in Embodiment 1, except that the three-phase star-connection method is adopted in the cascaded parallel unit 1 , because the zero-sequence component in the delta connection is an inner loop, because the star connection is more convenient to control the harmonics of each phase.

[0047] By adopting the above-mentioned structure of the present invention, the transformer connected to the grid side is canceled, and the intermediate frequency or high frequency transformer is used for electrical isolation. In the traditional way of using power frequency transformer isolation on the grid side, all the power on the parallel side must flow through the power frequency transformer, which makes the capacity and volume of the power frequency transformer larger. In the existing method, the p...

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Abstract

The invention discloses a cascaded unified electric energy quality regulating system, which comprises cascaded parallel connection units, inverse transformation units, isolation transformers, rectifier units, series connection units and a TSR (Thyristor Switch Reactor) branch, wherein the cascaded parallel connection units are formed by cascading a plurality of H bridge modules and are connected to a power grid; the inverse transformation units are used for carrying out inversion transformation on voltage on a direct current capacitor on each potential of the cascaded parallel connection units to form alternating current; the isolation transformers are used for transferring the alternating current formed by inverse transformation of the inverse transformation units to the rectifier units through a magnetic coupling manner; the rectifier units are used for transforming alternating current energy from the isolation transformers to a direct current side and carrying out voltage stabilization on the direct current voltage; the series connection units are formed by cascading a plurality of H bridge modules and are connected to a connection reactor Lc and a series capacitor Cc in parallel, and compensate through controlling an amplitude of the voltage and voltage harmonic of the output voltage about the load; the TSR branch is connected by a plurality of thyristors in series and is connected to a reactor Lg in series, and the reactor Lg is connected to a loop in series through controlling conduction of a thyristor string. The cascaded unified electric energy quality regulating system has the advantages of simple principle, easiness in implementation, wide application range, capability of greatly improving the electric energy quality, and the like.

Description

technical field [0001] The invention mainly relates to the technical field of power electronics, in particular to a cascaded unified power quality adjustment system for improving power quality. Background technique [0002] With the rapid development of science and technology and the national economy, the demand for electric energy has also greatly increased. However, with the increase of non-linear loads and impact loads in the power grid in recent years, such as the increase of electrified railways, electric arc furnaces and large-scale rectification equipment, the power quality is deteriorating day by day. [0003] In recent years, power quality has attracted widespread attention. Utilities have always been very concerned about operating at high power factor because high power factor operation reduces the required rating of equipment as well as line losses and voltage drops, thereby reducing the need for voltage conditioning equipment. However, the above-mentioned requi...

Claims

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Application Information

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IPC IPC(8): H02J3/00H02J3/18H02J3/16H02J3/01H02J3/28H02H9/02
CPCH02J3/00H02J3/01H02J3/16H02J3/18Y02E40/30Y02E40/40
Inventor 张定华张志学周方圆王卫安刘华东邱岳烽胡晓东范伟
Owner CSR ZHUZHOU ELECTRIC LOCOMOTIVE RES INST
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