Over-voltage protection method for DC bus voltage of wind power current transformer and circuit adopting same

A technology of DC bus voltage and overvoltage protection circuit, applied in the direction of emergency protection circuit devices, electrical components, etc., can solve the problems of difficulty in changing the overvoltage protection value, inflexible application of overvoltage protection circuit, etc., and achieve good linearity and practicality Strong, good effect

Inactive Publication Date: 2011-06-29
CSR ZHUZHOU ELECTRIC LOCOMOTIVE RES INST
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Problems solved by technology

The high voltage limit value of the overvoltage protection circuit using this method can only be changed by changing the hardware device, and the resistance value of the hardware device resistance is limited by the size of the circuit board pad, so basically a certain converter The DC bus overvoltage protection hardware determines the high limit value of the DC bus voltage, which makes the application of the overvoltage protection circuit very inflexible, and it is also very difficult to change the overvoltage protection value

Method used

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  • Over-voltage protection method for DC bus voltage of wind power current transformer and circuit adopting same
  • Over-voltage protection method for DC bus voltage of wind power current transformer and circuit adopting same

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Embodiment 1

[0025] A wind power converter DC bus voltage overvoltage protection method, in which a square wave with a certain amplitude, a certain frequency, and a certain positive duty ratio is generated according to the actual required DC bus voltage overvoltage protection value by means of DSP software look-up table, through Compared with a constant value, output a square wave with a certain amplitude, the same frequency, and the same positive duty cycle. This stage is called a first-level comparison circuit; the signal is then passed through an RC integrating circuit to obtain a constant value, which is the DC bus voltage Overvoltage protection value, which is compared with the actual detected voltage conversion value and then sent to the DSP to determine whether the DC bus voltage of the wind power converter is overvoltage. This stage is called a secondary comparison circuit.

[0026] Described one-stage comparison circuit is made up of the first comparator and the first voltage divid...

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Abstract

The invention discloses an over-voltage protection method for the DC bus voltage of a wind power current transformer and a circuit adopting the same. The method comprises the steps as follows: a square wave signal with a certain amplitude value, a certain frequency and a certain positive duty cycle is generated correspondingly according to the actually needed over-voltage protection value of a DC bus voltage by adopting the software table checking method of a DSP (Digital Signal Processor) chip; the square wave signal is compared with a normal value signal to output a square wave signal with a certain amplitude value, the identical frequency and the identical positive duty cycle, and the circuit completing the first time comparison output is a primary comparison circuit; the square wave signal receives special circuit treatment to be changed into a normal value signal reaching the pre-determinate over-voltage protection value of the DC bus voltage, the normal value signal and the conversion value of the actually detected DC bus voltage are compared to send an output signal to the DSP chip, and the circuit completing the second time comparison output is a secondary comparison circuit; and the DSP chip decides whether overvoltage exits in the DC bus voltage of the wind power current transformer.

Description

technical field [0001] The invention belongs to an overvoltage protection method and circuit, in particular to a wind power converter DC bus voltage overvoltage protection method and circuit. Background technique [0002] When the intermediate DC bus voltage exceeds a certain limit, the wind power converter will cause abnormal operation of the converter and is prone to failure. Therefore, the general converter will be used with the DC bus voltage overvoltage protection circuit. At present, in wind power converters, the DC bus voltage is mostly divided by resistors to obtain the upper limit value of the protected value, and the comparator outputs a signal representing the overvoltage of the DC bus voltage to the DSP. The high voltage limit value of the overvoltage protection circuit using this method can only be changed by changing the hardware device, and the resistance value of the hardware device resistance is limited by the size of the circuit board pad, so basically a ce...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02H7/22
Inventor 王莹王新泽佘岳刘憾宇刘志星张劲松郭知彼
Owner CSR ZHUZHOU ELECTRIC LOCOMOTIVE RES INST
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