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In order to solve the problem that the accuracy of flaws identification in ultrasonic testing is not high enough due to the error in sensor information acquisition and the noise interference in the detection environment, a method of flaws identification in ultrasonic testing based on evidential reasoning rule (ER rule) is studied. Firstly, ER rule is proposed to consider the reliability and weights...
The paper incorporates cable fault detection and location function to conventional SSPC (Solid State Power Controllers), which enhances the ability of fault diagnosis while improving fault coverage rate of the system, as well as realizing the precise positioning of cable fault distance. Aiming at the problem of relatively low cable fault detection rate of the cable positioning device, the concept...
Cost-sensitive multi-class fuzzy decision-theoretic rough set (MC_FDTRS) is proposed by considering cost sensitivity in practical fault diagnosis process. MC_FDTRS generalizes indiscernibility relation of multi-class decision-theoretic rough set to Gaussian kernel based fuzzy equivalence relation, and then it can deal with numerical data directly without discretization. MC_FDTRS introduces cost matrix...
In order to solve the problem of low accuracy of flaws detection in non-destructive testing, a data-fusion method based on RBF neural network and evidential reasoning (ER) rule is studied. Firstly, a data-fusion model is proposed which contains two parts. Secondly, the first part RBF neural network is used to fuse the feature layer, and its output is normalized as the basic probability assignment...
Due to the limited data variables of the spacecraft solar array, a comparison was made between the maximum power point voltage and current data of the solar array in the case of normal, short circuit, and irradiation failure. The maximum power point voltage and current data are used as the description of faults as the basis for fault diagnosis. Because of the cross-over phenomenon of the fault samples,...
In this paper, an optimal multi-degree open-circuit faults diagnostic algorithm, for improving condition monitoring ability of photovoltaics, has been proposed. This algorithm combines output parameters and characteristic impedance of PV-system under low frequency domain in simplified manner. The feasibility and accuracy of the method has been proven through simulation using Siemens-SM100-12.
In view of the fact that the integration of ICs is becoming higher and accessible testing nodes are getting less, circuit testing is becoming more and more difficult. A multidimensional feature fault diagnosis method based on principal component analysis is proposed in this paper. On the basis of analyzing the fault feature of analog circuits, the fault diagnosis method of multiple fault features...
To overcome the complex calculation and the interference vulnerability of traditional fault-diagnosis methods, this paper presents a fault diagnosis method for open-circuit faults of single converter device of the direct-driven permanent magnet wind power system on the basis of variable features of faulty current. The open-circuit fault of converters will seriously affect the operation of the direct-drive...
This paper studies the fault diagnosis of inertia navigation unit which plays an important role in inertia navigation system. The method chosen in the fault diagnosis is combined Genetic Algorithm and wavelet neural network. Wavelet transform will effectively handle the collected inertia navigation unit signal. The characteristic signals extracted will be regarded as inputs to the neural network....
Image acquisition devices which can get infrared image of solar modules is designed by using the principles of the semiconductor's electroluminescence, and image processing is applied to the detection system which can detect the defects automatically including black pieces, fragmentation, broken grid, crack and so on. At first the defects of the infrared image are classified and then the defects'...
Aiming at the online fault diagnoses, the texture features which are usually used in image processing are firstly applied in the early fault signal recognition problems. After the parameter R based on gray-level co-occurrence matrix is defined, the parameter R extraction method of texture features is presented. Then, the novel fault signal recognition algorithm based on the parameter R of the texture...
A novel on-line monitoring and fault diagnosis system of power transformer using basic principle of three ratio method based on DGA (Dissolved Gases Analysis) and PNN(Probabilistic Neural Networks) for engineering application is proposed. According to tested dissolved gases contents changing characteristic of transformer oils under different transformer working conditions, the five characteristics...
This paper presents a method to predict degradation path of products using time series modeling procedure based on product performance degradation data. The product performance degradation data are treated as a time series data and stochastic process are utilized to describe the degradation process for predicting long-term trend. A degradation test is processed for miniature bulbs until they failed...
The physics of failure (PoF) methodology is a primary approach for prognostics, especially for those of electronic products and assemblies. This paper summarizes the requirements for developing a generic field deployable prognostic software system using the model-based approach. It then proposes an implementation solution to design such a system while meeting those requirements. It in the end shows...
According to the fault of rotor bar breakage, the paper put forward a diagnosis method to extract the fault characteristic signal in stator current, by signal processing with Fourier Transform and wavelet transform theory. To validate its feasibility, simulation and experiment on frequency converter sets are made, and the results show that the given method perform well in the fault diagnosis application.
A novel working condition recognition system of screw compressor using wavelets for engineering application is proposed. According to tested rotor and valve vibration signal energy changing characteristic under different working condition of the compressor, the fault position and fault reason can be obtained clearly. The paper firstly obtained rotor vibration signal power distribution on different...
A novel working angle recognition system of screw compressor valve using wavelets and Probabilistic Neural Networks for engineering application is proposed. According to tested valve vibration signal energy changing characteristic under different working angle of valve flake, the paper obtains vibration signal power distribution on different scales using continuous wavelet transform, that is, scale-wavelet...
This paper presents both eigenvalue calculations and dynamic simulations to determine dynamic stability of multiple photovoltaic (PV) modules connected to a large utility grid. Each PV subsystem is connected to the utility grid through a DC-to-DC boost converter and a DC-to-AC three-phase inverter. The dynamic equations of the combined multiple PV systems are derived in detail to examine the dynamic...
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