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Method and arrangement in connection with a cascade-fed asynchronous generator

A technology of asynchronous generators and generators, which is applied in the direction of controlling generators, electrical components, and AC network voltage adjustment, etc., to achieve the effect of performance improvement

Active Publication Date: 2013-04-03
ABB (SCHWEIZ) AG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In this way, the rated grid maintenance cannot be generated by the frequency converter alone

Method used

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  • Method and arrangement in connection with a cascade-fed asynchronous generator
  • Method and arrangement in connection with a cascade-fed asynchronous generator

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Experimental program
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Embodiment Construction

[0012] For controlling a cascaded feedback generator, a frequency converter is used in a known manner and is connected between the generator rotor and the grid to be fed back. In known manner, a frequency converter comprises two inverters (ISU, INU) and a direct voltage intermediate circuit between the two inverters. figure 1 A schematic of the cascaded drive is shown. The grid-side inverter (ISU) of the frequency converter 1 is also called a network bridge or grid converter, while the generator-side inverter (INU) is called a load bridge.

[0013] During operation of the cascaded feedback generator 2 , the inverter (INU) on the generator side obtains measurement data of the voltage of the grid 3 and the current of the stator. When a grid voltage sag due to a grid fault is sensed, the inverter (INU) on the generator side excites the generator rotor in such a way that the generator starts feeding reactive current to the grid to maintain the voltage in the grid .

[0014] Acc...

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Abstract

A method and an apparatus for controlling a cascade-fed asynchronous generator in connection with a voltage dip of a network fed by the generator, wherein a frequency converter is connected between the rotor of the asynchronous generator and the network. The method comprises measuring the magnitude of the voltage in the network; calculating, on the basis of the voltage in the network, a base value for reactive current to be fed to the network; generating reactive current in the network by the generator; measuring the stator current; determining the actual value of the reactive current in the network; calculating the difference between the base value and the actual value of the reactive current; giving the calculated difference to the frequency converter to serve as an instruction in reactive current; and generating reactive current in the network by the frequency converter in accordance with the instruction in reactive current.

Description

technical field [0001] The present invention relates to cascaded feedback asynchronous generators and in particular to the control of such generators in the presence of disturbances in the grid. Background technique [0002] Cascade feedback or double feedback asynchronous generators are generally used in wind power plants as generators for generating electrical energy. When the cascaded feedback asynchronous generator is running, the stator of the generator is directly connected to the grid to be fed back, and the rotor of the generator is connected to the grid via a frequency converter. A frequency converter comprising two controllable bridges and a DC voltage circuit between the two bridges transmits the rotor power from the grid to the rotor circuit or from the rotor circuit to the grid depending on the rotational speed of the generator. Via a frequency converter, the rotor of the generator is excited according to the speed of rotation so that the voltage generated in t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/16
CPCH02P9/102H02P9/302H02P9/10H02P9/305
Inventor 雷约·卡莱维·弗塔嫩
Owner ABB (SCHWEIZ) AG