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Method for detecting output phase loss of frequency converter

A detection method and output phase loss technology, applied in the field of low-voltage inverters, can solve problems such as inaccurate judgment, inverter is not a complete sine wave, interference, etc., and achieve the effect of avoiding IGBT or other damage

Inactive Publication Date: 2016-04-06
长沙奥托自动化技术有限公司
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Problems solved by technology

This method can indeed complete the phase loss judgment when the three phases are all sine waves, but the output current waveform of the inverter is not a complete sine wave, and there will be great interference through the 2-parameter arctangent operation, resulting in inaccurate judgment

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  • Method for detecting output phase loss of frequency converter
  • Method for detecting output phase loss of frequency converter
  • Method for detecting output phase loss of frequency converter

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Embodiment Construction

[0014] The technical scheme of the present invention will be further described below in conjunction with the accompanying drawings and through specific embodiments:

[0015] against figure 1 The main circuit of the frequency converter shown uses a method for detecting the output phase loss of the frequency converter according to the present invention to detect the output phase loss.

[0016] First, the AD device of the CPU performs AD conversion on the three-phase current output by the frequency converter, discretizes the analog current and obtains the instantaneous value I of the three-phase current a , I b , I c , after α-β (Clark) transformation, the orthogonal I α and I β . Pass the obtained two-phase quadrature current through the following formula:

[0017] I 1 = I α ...

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Abstract

The invention provides a method for detecting the output phase loss of a frequency converter, and the method comprises the steps: firstly carrying out the AD sampling of a three-phase output current through the CPU of the frequency converter; converting the collected three-phase current alpha-beta into a two-phase coordinate, and respectively obtaining I<alpha> and I<beta>, which are orthogonal to each other; mapping I<alpha> and I<beta> to a composite plane, and enabling the composite plane to be divided into six sectors according to the polarity of the current; respectively placing a global variable in each sector, and continuously adding one to the global variables; taking the current output frequency of the frequency converter as a period, and judging the six global variables. If two or more global variables are zero, the frequency converter must be in a state of phase loss, and the frequency converter must be shut down. If no or one global variable is zero or all global variables are not zero, the frequency converter is normal, and the six global variables must be cleared as zero at this moment for next judgment.

Description

technical field [0001] The invention relates to the field of low-voltage frequency converters, in particular to a detection method for output phase loss of frequency converters. Background technique [0002] In the era of industrialization where frequency conversion is popular, the protection functions of frequency converters are becoming more and more perfect and more and more important. Among them, the inverter output phase loss is a very serious and very difficult fault, how to detect it accurately is very important. In the frequency converter, the output frequency is usually variable, and it is difficult to protect the frequency converter according to the traditional protection method; moreover, the IGBT in the frequency converter is very fragile, once the output current is seriously unbalanced due to the lack of output phase, It is very likely to damage the IGBT, so it is very important to quickly and accurately detect the lack of phase. Some literatures propose that ...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R29/16
CPCG01R29/16
Inventor 王亮彭云根秦建
Owner 长沙奥托自动化技术有限公司