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A frequency converter overcurrent protection method, device and frequency converter

A technology for overcurrent protection and frequency converters, applied in the field of devices, frequency converters, and frequency converter overcurrent protection methods, can solve problems such as failure to operate, large impact current, and current impact of frequency converters, etc., to ensure safe operation and simple implementation , the effect of improving stability

Active Publication Date: 2019-03-22
ZHUZHOU CSR TIMES ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When multiple inverters are connected in parallel, or a single inverter works in an environment with large fluctuations in the power grid, or there are other loads in the system, the possibility of system abnormality will be greatly increased, resulting in a large inrush current, frequent system protection, and failure to operate
If the method of increasing the threshold protection value is adopted, the inverter will be exposed to the risk of large current impact for a long time, which will have a significant impact on the performance of the inverter and related devices in the long run
If the strategy of canceling the over-current protection within a certain period of time is adopted, the above-mentioned possibility also exists, and the device may even be damaged due to the instantaneous impact of a huge current.

Method used

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  • A frequency converter overcurrent protection method, device and frequency converter
  • A frequency converter overcurrent protection method, device and frequency converter
  • A frequency converter overcurrent protection method, device and frequency converter

Examples

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Embodiment 1

[0030] Such as figure 1 As shown, the inverter overcurrent protection method in this embodiment includes the following steps: S1. Monitoring the current value of the inverter; S2. When the current value is greater than or equal to the preset first current threshold and the duration is greater than or equal to the preset first When the time threshold is reached, the frequency converter overcurrent protection start signal is triggered; S3. According to the frequency converter overcurrent protection start signal, the frequency converter overcurrent protection is started.

[0031] In this embodiment, step S2a is also included, and the specific steps are: S2a. When the current value is greater than or equal to the preset first current threshold repeatedly within the preset time period, but the duration is less than the preset first time threshold When the number of times is greater than the preset number of warnings, the frequency converter overcurrent protection start signal will ...

Embodiment 2

[0039] This embodiment is basically the same as Embodiment 1, the difference is that the inverter overcurrent protection method, such as figure 2 As shown, the judgment process of step S2b is before step S2. Certainly, the order of starting the over-current protection according to the strategy for judging the monitored current value can be flexibly adjusted according to needs. In this example, if Figure 8 As shown, the inverter overcurrent protection device judges the monitoring current value through the current monitoring module. When the current value is greater than or equal to the preset second current threshold, the inverter overcurrent protection start signal is triggered; the second current threshold is greater than the first a current threshold. Since the instantaneous large current may cause damage to the inverter in a very short time, and the current monitoring module collects current data and sends it to the calculation module for calculation and analysis, it is...

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Abstract

The invention discloses a frequency converter overcurrent protection method, device and frequency converter. The method includes: S1. monitoring the current value of the frequency converter; S2. when the current value is greater than or equal to a preset first current threshold and lasts When it is greater than or equal to the preset first time threshold, the inverter overcurrent protection start signal is triggered; S3. According to the inverter overcurrent protection startup signal, the inverter overcurrent protection is started; the device includes a current monitoring module, a calculation module and Overcurrent protection module; the frequency converter includes the device. The invention has the advantages of simple implementation, multiple protections can be effectively realized, and high reliability, which can not only ensure the safe and stable operation of the frequency converter system, but also ensure that the system will not be affected by long-term extreme working conditions, and greatly improve the system stability.

Description

technical field [0001] The invention relates to the field of frequency converter overcurrent protection, in particular to a frequency converter overcurrent protection method, device and frequency converter. Background technique [0002] With the continuous improvement of users' requirements for power and low-carbon energy saving, the application of frequency conversion drive system is developing towards the trend of high power and even parallel connection of multiple frequency converters. More and more high-power frequency converters are beginning to try to use in parallel. [0003] However, in the process of parallel use, each inverter has a starting sequence according to the demand during use. When the inverter that is put into use later is connected to the grid, there is a voltage difference with the inverter that is connected to the grid first, resulting in The inrush current is several times larger than normal operation. Once the inrush current exceeds the protection th...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M1/32H02H9/02
CPCH02H9/02H02M1/32H02M1/325
Inventor 喻通胡家喜何亚屏姚大为刘辉荣韩志成胡斌炜黄启钊孟文辉杨卓杨啸聪许世雄郭兵
Owner ZHUZHOU CSR TIMES ELECTRIC CO LTD