Three-level inverter multi-mode fault diagnosis circuit and diagnosis method thereof

Abstract

The invention relates to a three-level inverter multi-mode fault diagnosis circuit and a diagnosis method thereof. Voltage signals of an upper bridge arm, a middle bridge arm and a lower bridge arm of each phase of bridge arms of an NPC three-level inverter are collected. A bridge arm voltage fault feature extraction module extracts fault features of the voltage signals and then sends the fault features to a neural network module to be analyzed. Voltage of each middle bridge arm is measured through a main neural network module so that eleven fault modes, including a fault-free mode, of an open circuit of a single-bridge-arm component of the three-level inverter can be diagnosed. Voltage of each upper bridge arm and voltage of each lower bridge arm are measured through two auxiliary neural network modules so that the other four fault modes of the open circuit of the single-bridge-arm component of the three-level inverter can be diagnosed, and by combination of the three neural network modules, thirteen multi-fault modes of the open circuit of each single-bridge-arm component of each phase of the bridge arms of the three-level inverter and simultaneous open circuits of multiple components of each phase of the bridge arms of the three-level inverter are diagnosed together. According to the three-level inverter multi-mode fault diagnosis circuit and the diagnosis method thereof, fault components can be exactly positioned, the algorithm structure is simplified, calculation of a Hessian matrix can be avoided, and accordingly the calculation amount and internal storage demands in a training are reduced, the operation speed is high, the diagnosis accuracy is high and the anti-interference capacity is high.

Description

technical field [0001] The invention relates to a power device fault diagnosis technology, in particular to a multi-mode fault diagnosis circuit and a diagnosis method for a midpoint-clamped three-level inverter with a multi-neural network structure. Background technique [0002] Compared with the traditional two-level inverter, the multi-level inverter has the advantages of increasing the number of output levels, better harmonic spectrum, and less voltage stress on the device, but because the multi-level circuit uses a large number of More switching devices lead to a corresponding reduction in the reliability of the circuit, and any device failure may cause the entire circuit to stop working, and even affect the safety of other circuits, resulting in immeasurable economic losses. [0003] At present, many technical methods have been developed for fault diagnosis of diode neutral-point clamped (NPC) three-level inverters at home and abroad. For example, analyze the circuit ...

AI Technical Summary

Problems solved by technology

[0004] The invention aims at the problem that the multi-level inverter circuit is prone to failure, and proposes a three-level inverter multi-mode fault diagnosis circuit and its diagnosis method. The circuit can diagnose each phase bridge of the NPC three-level inverter A total of 13 multi-fault modes, including single device open circuit and multiple devices open circuit at the same time, can accurately locate the faulty device, and the algorithm structure is simplified, which can avoid the calculation of Hersey matrix, thereby reducing the amount of calculation and memory requirements in training. blocks, high diagnostic accuracy and strong anti-interference ability

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