Fault diagnosis method and device for cascaded H-bridge photovoltaic inverter

Abstract

The invention provides a fault diagnosis method and device for a cascaded H-bridge photovoltaic inverter, and belongs to the technical field of photovoltaic power generation. The method comprises the following steps: setting a cascaded H-bridge photovoltaic inverter topological structure, and controlling the grid-connected current of the cascaded H-bridge photovoltaic inverter; analyzing the fault mode of the cascaded H-bridge photovoltaic inverter; carrying out feature extraction by adopting wavelet packet energy entropy; an improved bacterial foraging optimization algorithm is adopted to solve the optimal kernel function bandwidth and bias; and according to the optimal kernel function bandwidth and bias, training data by using a support vector machine and carrying out fault diagnosis. Compared with an SVM fault diagnosis method, the improved bacteria optimization algorithm is used to optimize the SVM fault diagnosis method, so that feature extraction of the switch tube fault of the cascaded H-bridge photovoltaic inverter is realized, and diagnosis and classification of the switch tube fault of the cascaded H-bridge photovoltaic inverter are realized. And the accuracy of open-circuit fault diagnosis of the three-phase cascaded H-bridge photovoltaic inverter can be effectively improved.

Description

technical field [0001] The invention belongs to the technical field of photovoltaic power generation, and in particular relates to a fault diagnosis method and device for a cascaded H-bridge photovoltaic inverter. Background technique [0002] Energy is the driving force for the development of a country. The current main form of energy supply in my country is still thermal power generation, relying on fossil fuel combustion to obtain steam power to drive the generator rotor to rotate to generate electricity. However, the renewable speed of fossil fuels is very slow, and the output and consumption are not consistent. In addition, the consumption of fossil fuels will cause greater harm to the ecological environment. In order to alleviate these problems, clean and sustainable new energy sources have emerged as the times require, and have become the main direction of technological research. [0003] Photovoltaic power generation uses photovoltaic panels to convert the energy in s...

AI Technical Summary

Problems solved by technology

Among them, the cascaded H-bridge, as one of the multi-level topology structures, has the characteristics of simple circuit and easy expansion. However, for a system with a large number of cascaded H-bridge units, the number of switch tubes increases exponentially, and each switch tube are potential failure points

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