Decision tree SVM fault diagnosis method for three-level inverter of photovoltaic diode clamp type

Abstract

The invention discloses a decision tree SVM fault diagnosis method for a three-level inverter of a photovoltaic diode clamp type. Aiming at a fault diagnosis problem of the three-level inverter in a photovoltaic microgrid and taking an inversion state as an example, the method comprises the steps: firstly analyzing the operation state of an inverter main circuit, and carrying out the fault classification; secondly taking three bridge arm voltages (middle, upper and lower) as measurement signals, and extracting characteristic signals through employing a wavelet multi-scale decomposition method, thereby generating a decision tree SVM classification model through employing a particle clustering algorithm; finally achieving the multi-mode fault diagnosis of the three-level inverter of the photovoltaic diode clamp type. The method is advantageous in that the method can clearly distinguish all fault states of the three-level inverter of the photovoltaic diode clamp type, employs a smaller number of classification models to complete the fault diagnosis task, is high in diagnosis precision, and is strong in anti-interference capability.

Description

technical field [0001] The invention relates to the field of fault diagnosis of power electronic devices, in particular to a decision tree SVM fault diagnosis method for a photovoltaic diode clamp type three-level inverter. Background technique [0002] The global energy crisis and environmental crisis have prompted people to seek cleaner and greener new energy sources. Among clean energy sources, solar energy has attracted widespread attention due to its advantages of non-pollution, sustainability, universality, flexibility and reliability. As more and more photovoltaic systems are integrated into the power grid, photovoltaic inverters, as the core components of photovoltaic systems, are related to the safe, stable and efficient operation of the entire system. Compared with the traditional two-level inverter, the three-level inverter has been widely used in photovoltaic power generation systems due to its advantages of series voltage equalization of switching devices, small...

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Problems solved by technology

However, the three-level inverter increases the number of switching devices, and the reliability of the circuit is correspondingly reduced. The failure of any one device may lead to abnormal operation of the circuit, and even lead to secondary failures, resulting in huge economic losses.

[0003] The problems of fault diagnosis of photovoltaic three-level inverters are mainly in three aspects: First, in terms of circuit fault mode, only the fault of a single device open circuit is considered. There are still few studies in this area, and the analysis of the problem is not comprehensive enough, and the algorithm structure of the existing fault diagnosis method for two switching devices being open at the same time is relatively complicated; second, the detection signals are mostly output voltage and output current, because there is For ind

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