Research Of DC System Fault Diagnosis Based On Neural Network And Data Fusion

This paper mainly studies the fault diagnosis method of DC power supply net in factories and corporation, on the basis of analyzing the strongpoint and shortcoming of the diagnosis method now in use, we propose a new idea about using neural networks and data fusion method to diagnose the fault of DC power supply net. First, the paper studies in detail wavelet theory and multiresolution analysis in function space, and then brings forward a new neural network called multiresolution neural network,the struture and algorithm of which will be discussed together. The network can extract a sine wave or other signal maybe contaminated by noise on DC net, this virtue of it can help to handle the character of DC fault. But, on the other hand, the sensor maybe fault or becoming less precision itself, so using only one sensor may lead to error diagnosis result, the paper apply data fusion technology to solve the problem. On the basis of studying neural network and D-S evidence theory, we bring forward a method of combining these two theories to form a fault diagnosis system which has the character of data fusion. The system can synthesize the information of multi-sensors to get a more powerful and precision result, avoiding some error-results caused by the faults or saturation of single sensor or the uncertainty of BP networks output furthest. The paper uses an emulator called simulink and a module called SimPowerSystems of MATALB to build up a model of DC power supply system, on the basis of which, we will verify the theories introduced above.The realization scheme of this project is also discussed in the paper, a data pick-up/control board using PCI bus protocol is designed, this board together with some softwares can finish many functions such as AD conversion of DC system generatrix and every DC spur track, sine wave generation which frequency is between 0-50Hz , and some control functions in fault analysis system. Furthermore, this paper also discussed some key technologies in software programming such as how to program WDM driver for the board and how to link MATLAB programs in VC++ by COM method.