Open-circuit fault diagnosis method of single-phase three-level rectifier in high-speed railway traction system

Abstract

The invention provides a method for diagnosing and locating an open circuit fault of a switch tube of a single-phase three-level rectifier of a high-speed rail traction system, belonging to the field of fault diagnosis. The method includes the following steps: establishing a hybrid logic dynamic model, establishing a new adaptive sliding mode observer, proposing an adaptive threshold for primary diagnosis, primary fault diagnosis, proposing an adaptive threshold for secondary diagnosis, diagnosing and locating secondary faults, and proposing tertiary diagnosis Adaptive threshold, three fault diagnosis and localization. The adaptive sliding mode observer proposed by the present invention does not require the system to provide a very accurate dynamic model, but only needs to use the tracking error of the trajectory to reasonably design the sliding mode surface, and can adaptively switch the approach rate, thereby speeding up the approach speed. And the chattering of the sliding mode motion is reduced, and the accuracy of diagnosis is improved; the method can diagnose and locate the fault of the switch tube by comparing the relationship between the residual feature quantity and the adaptive threshold.

Description

technical field [0001] The invention relates to the field of fault diagnosis, in particular to a method for diagnosing an open circuit fault of a switch tube of a single-phase three-level rectifier of a high-speed rail traction system. Background technique [0002] High-speed rail traction drive system is an important part of high-speed trains, and its safety and reliability directly affect the operation of high-speed trains. The traction rectifier is one of the core components of the high-speed railway traction drive system, which is prone to failure, resulting in serious casualties and property losses. [0003] The traction rectifier is a single-phase three-level rectifier, and the diagnosis method of the open-circuit fault of the switch tube of the single-phase three-level rectifier is mainly divided into the following two diagnosis methods according to the characteristics of the diagnosis object: [0004] 1. Diagnosis method based on current characteristic quantity. Th...

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Problems solved by technology

Specifically, through the sliding mode observer and the use of sliding mode control, the problem of difficulty in establishing an accurate system model can be solved only by rationally designing the sliding mode surface, but this method will produce jitter characteristics during the control process, and then design Adaptive approach rate, through the adaptive switching approach rate to reduce the jitter characteristics in the control process, and further improve the accuracy of system fault diagnosis; at the same time, when performing fault diagnosis based on the characteristic quantity of current, by designing the adaptive threshold To suppress the inherent or external uncertain disturbances of the system, increase the accuracy of the diagnostic method, and improve the diagnostic accuracy; finally, in the fault location, according to the fault system model, an adaptive sliding mode observer under the specific open circuit fault state of the switching tube is established to Reproduce the system grid-side current output when a specific switch tube open circuit fault occurs and compare it with the actual sampled grid-side current to locate the faulty switch tube

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