Evidence reasoning rule-based voltage source-type inverter DC bus capacitor fault diagnosis method

Abstract

The invention relates to an evidence reasoning rule-based voltage source-type inverter DC bus capacitor fault diagnosis method. The method obtains a voltage characteristic value from the voltage source-type inverter and sets three levels of capacitor failure fault. The input of the built evidence reasoning fault diagnosis model is two-dimensional voltage characteristics and the output is reliability distribution of a failure fault level. According to the given voltage characteristic reference value, a fault reliability distribution matrix is built, the matrix is used to convert the input to adiagnosis evidence, the reliability factor of the diagnosis evidence is calculated, and then, two-dimensional input activation evidences are fused, and the level of the capacitor failure fault is estimated from the fusion result. Parameter optimization is carried out on the built diagnosis model, the fault level of a sample capacitor can be estimated and tested based on the optimized diagnosis model, and fault diagnosis on the capacitor can be realized.

Description

technical field [0001] The invention relates to the field of fault diagnosis of electric power systems, in particular to a fault diagnosis method for DC bus capacitors of voltage source frequency converters based on evidence reasoning rules. Background technique [0002] With the continuous development of the power system, there are more and more application occasions, which have brought huge economic benefits to the development of all walks of life. As the basic components of the voltage source inverter, the capacitor plays the role of filtering, energy storage, tuning, etc., especially on the DC bus, the capacitor plays a role in stabilizing the DC bus voltage. As the working time becomes longer, the capacitor ages and the capacitance decreases. At this time, the voltage source inverter can still work, but the performance will gradually decrease. This small fault is difficult to identify, and it is not easy to activate the system protection. Long-term operation will affec...

AI Technical Summary

Problems solved by technology

At this time, the voltage source inverter can still work, but the performance will gradually decrease. This small fault is difficult to identify, and it is not easy to activate the system protection. Long-term operation will affect the service life of the equipment.

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