A method for igbt open-circuit fault location of three-level active filter

Abstract

The invention discloses a three-level active filter IGBT open-circuit fault positioning method and belongs to a frequency converter IGBT fault diagnosis method. According to the fault positioning method, level of a three-phase output point X of an active filter for a midpoint M of a DC bus is observed through two concrete methods, and positions of IGBTs specifically generating open-circuit faults are determined through similarity comparison. One method is that a level difference of the three-phase output point X for the midpoint M of the bus is solved in real time through a circuit theoretical loop equation, for representing an actual real level difference. The other method is that first of all, it is assumed that four X-phase IGBTs are respectively open-circuited, the level difference of the three-phase output point X for the midpoint M of the bus after the four X-phase IGBTs are open-circuited is obtained through current loop analysis reckoning, for representing a reckoned level difference. Since there is one, and only one waveform close to the level difference solved through the first method in the reckoned level difference, the faults can be determined. The method has the following advantages: 1, the method is independent from load types; 2, an accurate diagnosis can still be made under the condition of load abrupt change; 3, the accuracy is high; and 4, additional hardware cost is unnecessary.

Description

technical field [0001] The invention relates to a frequency converter IGBT fault diagnosis method, in particular to a three-level active filter IGBT open circuit fault location method. Background technique [0002] Frequency converters are widely used in the field of motor speed regulation. Frequency converters must use power switching devices with high switching frequencies. Power switching devices are often damaged. Once a power device fails, it will affect the system work or even cause shutdown. According to statistics, power device faults account for more than 70% of inverter faults. Therefore, it is very important for inverters to quickly and effectively locate faults in power devices and take protection and fault tolerance measures. [0003] The research has found many fault diagnosis methods for inverter power devices, such as PARK vector method, neural network method and so on. These methods are only applicable to the frequency conversion speed regulation system, ...

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a three-level active filter IGBT open-circuit fault location method to solve the problem that the power device fault judgment of the existing active filter is very difficult

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