Inverter power transistor open circuit fault diagnosis method

Abstract

The invention discloses an inverter power transistor open circuit fault diagnosis method. The method comprises steps: an envelope function for fault line voltage of the inverter is defined firstly; output line voltage of the inverter is acquired; pretreatment is carried out on the output line voltage to acquire effective fault information; according to the effective fault information and in combination with the line voltage envelope function, voltage distortion features caused by open circuit fault are obtained; and according to the voltage distortion features, a fault bridge arm is positioned. According to the inverter power transistor open circuit fault diagnosis method disclosed by the invention, system control signals do not need to be acquired, the fault can be positioned generally in a carrier period, the diagnosis process has nothing to do with the inverter control mode and the load, the robustness is good, the diagnosis circuit structure is simple, and the method can also be used for bridge arm open circuit fault diagnosis for other three-phase inverter circuits.

Description

technical field [0001] The invention relates to the field of inverters based on PWM technology, in particular to a method for diagnosing open-circuit faults of inverter power tubes. Background technique [0002] Inverters based on PWM technology are widely used in the industrial field, and their reliability is very important, but the faults of the converter system cannot be completely eliminated at present. Therefore, the fault diagnosis technology for the converter system has become a research topic in recent years. hot spot. Industrial converter system faults are mainly composed of capacitor faults, semiconductor power tubes and their drive circuit faults. [0003] Starting from the object of fault diagnosis, the results of fault diagnosis can be divided into two categories. The first category of results is aimed at diagnosing component failures. This type of fault diagnosis requires a deep understanding of the physical characteristics and structures of capacitors and pow...

AI Technical Summary

Problems solved by technology

[0003] Starting from the object of fault diagnosis, the results of fault diagnosis can be divided into two categories. The first category of results is for the diagnosis of component failures. This type of fault diagnosis requires an in-depth understanding of the physical characteristics and structures of capacitors and power semiconductor devices. Currently, there are The accuracy of the fault model is not high, and the fault features are difficult to extract, etc.

[0004] The second category of achievements is aimed at diagnosing circuit structure faults caused by component failures. Circuit structure faults mainly include bridge arm short circuit and open circuit. Among them, short circuit faults are very destructive, and the system needs to be shut down instantly through the protection circuit to protect the remaining components; open circuit The failure does not necessarily cause the system to crash instantaneously, but it may cause secondary damage to other devices, eventually leading to system failure

This type of method needs to collect the trigger pulse of the converter as a diagnostic variable, or integrate the diagnostic method into the control system, which is difficult to achieve for the converter system that has been in service; some methods also need to add sensors to obtain specific variables, or use load-affected The larger output current is used as the basis for diagnosis; in addition, some methods have a large amount of calculation and need to add complex diagnostic circuits

These shortcomings make the current fault diagnosis methods difficult to popularize and apply.

Images