Soft starting method improved based on H-bridge cascade STATCOM (Static Synchronous Compensator)

A soft start and cascading technology, which is applied in flexible AC transmission system, reactive power adjustment/elimination/compensation, etc., can solve the problems of large inrush current and limited output capacity of the device, so as to enhance the output voltage capability and increase the capacitor voltage Steady-state value, the effect of avoiding shock

Active Publication Date: 2014-11-05
SHANXI LUAN MINING GRP +1
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Problems solved by technology

After the pre-charging process is over, the output voltage and current phasor diagram when the device is transferred to no-load operation is as follows: image 3 As shown in (a), since the capacitor voltage on the DC side of the uncontrolled rectification stage is not enough to rise to a h

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  • Soft starting method improved based on H-bridge cascade STATCOM (Static Synchronous Compensator)
  • Soft starting method improved based on H-bridge cascade STATCOM (Static Synchronous Compensator)
  • Soft starting method improved based on H-bridge cascade STATCOM (Static Synchronous Compensator)

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[0050] In order to make the objectives, technical solutions and advantages of the present invention clearer, the following combination Figure 4 And examples, the present invention will be further described in detail. Figure 4 Middle, u sx , I sx Is the phase voltage and phase current of the grid side, where x is a, b, c, R is the current limiting resistance, L is the connected reactor, u dcxm Is the detection value of the DC side voltage of each unit of the device, Is the given value of DC side voltage, Is the average value of the DC side voltage of the unit, i ox Is the output current detection value of the device, It is a modulated wave signal. It should be understood that the specific embodiments described here are only used to explain the present invention, but not to limit the present invention.

[0051] The present invention provides an improved soft start method based on H-bridge cascade STATCOM, and the specific implementation steps are as follows:

[0052] Step (1) W...

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Abstract

The invention relates to a soft starting method improved based on an H-bridge cascade STATCOM (Static Synchronous Compensator). The method is characterized by comprising the main steps of: accessing a current-limiting resistor in series during starting of the STATCOM, controlling pulse signals of all unit switch devices so as to absorb active power provided by a power grid to the greatest extent, and pre-charging a device; removing the current-limiting resistor after pre-charging is completed, and forwarding the device into an idle running period; providing a voltage given value of a DC side by a voltage gradually-increasing method during idle running period; and stably increasing the voltage of the DC side into the given value; forwarding into a load running period and completing the starting process. According to the soft starting method of the device, provided by the invention, the pulse signal of all unit switch devices are controlled from a pre-charging period, harmonic distortion rate of the output current of the device during the pre-charging period is greatly reduced, and the voltage steady-state value of the DC side is also effectively improved during the pre-charging period; and the voltage given value of the DC side is provided by a voltage gradually-increasing method, so that the capacitor voltage of the DC side can be stably increased into the given value without overshoot.

Description

technical field [0001] The invention relates to an H-bridge cascaded static synchronous compensator, in particular to an improved soft start method based on the H-bridge cascaded STATCOM. Background technique [0002] The H-bridge cascaded STATCOM has the advantages of modularization and easy expansion, and has broad application prospects in the field of medium and high voltage reactive power compensation. The H-bridge cascaded STATCOM main circuit topology is as follows: figure 1 As shown, each phase of the device has n inverter units cascaded, and each inverter unit has an independent capacitor on the DC side for energy storage, providing DC voltage support for STATCOM. The STATCOM three-phase commutation chain is connected in star form, and connected to the grid through connecting reactors. figure 1 L is the connecting reactor of the device, u dc1 , u dcn are the DC side capacitor voltages of A-phase unit 1 and unit n, respectively. [0003] Soft-start technology is ...

Claims

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Application Information

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IPC IPC(8): H02J3/18
CPCY02E40/10
Inventor 周娟杨擎杜少通王福均宋振浩郑婉玉刘马隆高超绪魏琛王晓莹楚程媛汪山林
Owner SHANXI LUAN MINING GRP
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