Inverter power transistor open-circuit fault real-time detection method in motor driving system

Abstract

The invention discloses an inverter power transistor open-circuit fault real-time detection method in a motor driving system, which belongs to the technical field of online detection. The method comprises steps: a width of a sliding window is calculated, function values Pn and Fn of two isopotential point functions for three-phase current defined by the sliding window and residuals R<1>n and R<2>n are calculated in real time, if the residual R<1>n is not equal, fault happening is judged, and fault is classified into four types according to the criteria of the isopotential point functions; and according to comparison results between positive and negative values of the isopotential point functions and corresponding residual values and corresponding thresholds, specific fault positioning is realized. The method of the invention can be applied to open-circuit fault diagnosis for any single transistor and any dual transistor of the inverter in the motor driving system, and has the advantages of low cost, high detection precision, quick speed, high real-time performance, good robustness and strong anti-interference ability.

Description

technical field [0001] The invention belongs to the technical field of on-line detection, and more specifically relates to a real-time detection method for an open-circuit fault of an inverter power tube in a motor drive system. Background technique [0002] At present, as a device for converting electrical energy and mechanical energy, AC motors have been widely used in the fields of aerospace, military, industry, locomotive traction systems and ships, showing a trend of completely replacing DC motors. As the core component of the AC motor drive system, the inverter is the weakest link in the drive system that is most likely to fail. Among them, the open-circuit fault caused by the high-frequency turn-on and turn-off of the power tube is particularly significant, which directly affects the normal operation of the motor drive system. . Aiming at the open-circuit fault of the inverter power tube, a real-time and effective detection, location and isolation method are proposed...

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Problems solved by technology

This method depends on the motor parameters to a large extent, and the parameters of the motor are uncertain in actual operation, so this method has certain deficiencies in engineering applications; 2. Based on the method of detecting voltage, according to the fault power tube The characteristics of voltage distortion, fast real-time detection and positioning, this type of method needs to add corresponding sensors and detection circuits to the hardware, which increases the cost of the monitoring system; 3. Based on the method of detecting current, according to the output of the inverter Three-phase current, analyze the system failure mechanism in the α-β coordinate system and the d-q coordinate system respectively, and perform fast and real-time detection and positioning. This type of method needs to estimate the synchronous rotation angle, and the estimation error will affect the detection accuracy.

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