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A Method for Improving Low Voltage Ride Through Performance of Doubly-fed Converter

A low-voltage ride-through, converter technology, applied in the direction of single-grid parallel feeding arrangement, etc., can solve the problems of mechanical shaft vibration, system instability, system power mutation, etc.

Inactive Publication Date: 2015-08-12
北京科诺伟业科技股份有限公司 +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Blocking the pulse will cause a sudden change in the power of the system, causing the mechanical shaft to vibrate, and repeatedly blocking the pulse may also cause system instability

Method used

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  • A Method for Improving Low Voltage Ride Through Performance of Doubly-fed Converter
  • A Method for Improving Low Voltage Ride Through Performance of Doubly-fed Converter
  • A Method for Improving Low Voltage Ride Through Performance of Doubly-fed Converter

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Embodiment Construction

[0045] specific implementation

[0046] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0047] Three-phase general-purpose inverter electrical topology such as figure 2 As shown, by the DC bus U dc , S aup , S adn composed of phase A bridge arm, S bup , S bdn composed of phase B bridge arm, S cup , S cdn Composed of C-phase bridge arm, three-phase series inductor L a , L b , L c and load U s Composition, V ca , V cb , V cb Output three-phase voltage for the inverter, V sa , V sb , V sc is the load three-phase voltage.

[0048] As described below, the present invention controls the grid-side converter and the motor-side converter respectively:

[0049] The control method of the present invention for the power grid side converter is as follows:

[0050] (1) When the program is initialized, set I according to the capacity of the converter goc1 , I goc2 two current thresholds, and...

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Abstract

The invention relates to a method for improving a double-fed converter low voltage ride through performance. The method is characterized in that a current transformer on a power grid side and a current transformer on a motor side are respectively subjected to different force pulse control according to overcurrent degree. The method comprises the following steps of: after detecting overcurrent, finding a maximum current phase and a current sign thereof, if the maximum current phase is larger than 0, conducting a whole switching period through a phase lower switch tube, and controlling by utilizing 0 voltage, and if the maximum current phase is less than 0, conducting the whole switching period through a phase upper switch tube, and controlling by utilizing full direct-current voltage; judging the overcurrent degree, wherein when the overcurrent is slightly larger, non-overcurrent two phases output a normal PWM (Pulse-Width Modulation) signal, and restrain the overcurrent, when the overcurrent is still larger, non-overcurrent two phase output is opposite to the maximum current, and the increasing of the overcurrent is restrained extremely; for the current transformer on the motor side, when the overcurrent is larger, blocking a three-phase pulse; and if the current is increased to trigger a Crowbar threshold value, inputting into a Crowbar circuit so as to protect a power electronic device.

Description

technical field [0001] The invention relates to the field of wind power converters, in particular to a control method for improving low-voltage ride-through performance of double-fed wind power converters. Background technique [0002] Soaring oil prices and enhanced awareness of environmental protection have made people pay more and more attention to renewable energy. As one of the most competitive renewable energy power generation methods, wind power has developed rapidly, accounting for an increasing proportion of global power generation. The stability and reliability of power generation are getting more and more attention. Power grid companies around the world have successively issued strict technical regulations for connecting wind farms to the grid, including grid fault ride-through capabilities. When there is a short-term drop in the grid, the wind turbines can be connected to the grid to generate electricity, and even support the recovery of the grid by generating r...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38
Inventor 吕佃顺林资旭马强李海东武鑫赵栋利郭金东赵斌许洪华
Owner 北京科诺伟业科技股份有限公司
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