More Electric Aircraft Electrical System Fault Diagnosis Research

More electric aircraft is an important feature of the next era of advanced fight aircraft. The performance and safety of the overall more electric aircraft is decided by the quality of its power system. Only when the faults of the system are detected and diagnosed in time, can it be assured that efficient measures are taken to avoid the enlargement of faults, reaching the goal of improving the systematic safety and reliability. In a word, the research of more electric aircraft power system's fault diagnosis is necessary.The paper focuses on the application of the theories of Expert System and Neural Network in the fault diagnosis of electrical power system of more-electric-aircraft respectively. The design and realization of the more-electric-aircraft electrical power system fault diagnosis software are then introduced in detail. The fault diagnosis software of power supply system applying the Expert System Theory is programmed under VB 6.0. While the fault diagnosis of electric load manage center and solid state power controller is based on the Neural Network Theory, whose software is realized through adopting the Neural Network Toolbox of Matlab 6.1 in VB 6.0. Procreant knowledge expression and forward inference engine are adopted in the method of fault diagnosis based on Expert System Theory. In the fault diagnosis applying Neural Network Theory, six kinds of improved arithmetic of back-propagation arithmetic, including gradient descent with momentum, variable learning rate back-propagation, resilient back-propagation, quasi-Newton, Levenberg-Marquardt and conjugate gradient, are applied to diagnose the faults of electric load manage center and solid state power controller. Different diagnostic results gotten by simulation are compared at last.The paper is significant in the study of fault diagnosis and fault-tolerant control. The method and the simulation results of the paper are the basis of the detailed design of electrical power system and the development of prototype airplane in future.