t-type three-phase four-wire rectifier fault real-time detection and location method and system

Abstract

The invention discloses a T-type three-phase four-wire rectifier fault real-time detection and positioning method and system, belonging to the technical field of online fault diagnosis. The method includes: firstly using the zero-domain current threshold and the fault detection judgment threshold to detect the fault; after detecting the fault of the power tube, using the polarity of the three-phase current after the time delay ΔT and the polarity of the three-phase modulation voltage during the occurrence of the open-circuit fault Changes to obtain accurate fault location results. It has high real-time performance. When performing fault detection, the present invention utilizes the characteristic that the current in the fault interval will be quickly reduced to near zero due to the influence of the bus capacitor voltage, and sets the zero domain current threshold for fault detection, which has high real-time performance; when fault location, It only needs to analyze the current and modulated voltage signals, does not need system parameters such as system inductance, is not sensitive to changes in system parameters, has good robustness, and strong anti-disturbance ability.

Description

technical field [0001] The invention belongs to the technical field of online fault diagnosis, and more specifically relates to a method and system for real-time fault detection and location of a T-type three-phase four-wire rectifier. Background technique [0002] In recent years, with the rapid development of new energy technology, more and more new energy vehicles have appeared one after another. As an important charging module of the new energy vehicle charging pile, the stability of the rectifier is an important indicator to consider the quality of the system. In the rectifier, the power tube is easily turned on and off due to high frequency to cause an open circuit fault, which directly affects the normal operation of the system. T-type three-phase four-wire rectifiers are widely used in rectifier modules of charging piles due to their superior performance. Researching real-time and effective diagnostic methods for open-circuit faults of T-type three-phase four-wire ...

AI Technical Summary

Problems solved by technology

[0003] At present, most of the real-time diagnosis methods for open-circuit faults of three-phase three-level rectifiers are based on signal processing methods such as Fourier transform and wavelet transform, and then optimize the combination of feature quantities to realize fault diagnosis. These signal processing methods require complex mathematical calculations. Increases the CPU calculation burden; for three-phase three-level rectifiers, additional filtering operations will lose fault information, resulting in indistinct features; selecting the threshold value based on experience or fixing the threshold value will cause problems such as low robustness of the diagnostic algorithm

Existing methods such as signal-based residuals need to add capacitive voltage sensors to improve accuracy, which increases the cost of diagnosis

Images