Reliability Analysis Of Aircraft Electric Power System Based On Equal Topology Network-probability Network

Aircraft electrical power system(AEPS)is one of the most important systems to ensure that the aircraft completes all kinds of flight tasks.The performance of AEPS is the decisive factor for the normal function of airborne electrical equipment,and its reliability is an important guarantee for flight safety operation.The electrical power system has multiple buses,and each bus is connected to one or more power devices.The bus is an important connection part of the power generation system and the power distribution,the aircraft power consumption device mainly uses electricity through the buses.Therefore,the reliability of the terminal bus provide electricity normally determines the power supply safety of the AEPS.It is important to analyze the reliability of the power supply terminal bus through complex system reliability modeling and analysis methods,which is of great significance for determining the power supply reliability of AEPS and even the operational safety of the aircraft.The power supply reliability of the terminal buses of the aircraft power system is analyzed,and a method of power supply reliability analysis of the bus by establishing the equal topology network-probability network of the aircraft power supply system is proposed.Firstly,according to the working principle of power supply system,the system functional structure diagram is determined,and the mapping relationship between input and output flow of components in the system functional structure diagram is divided.Then,according to the mapping relationship of the components in the system,the node with the same name corresponding to the component and the auxiliary node with the same name are established,and then the equal topology network with the qualitative description system of the functional structure diagram is established.Finally,by the auxiliary node with the same name are established,and then the equal topology network with the qualitative description system of the functional structure diagram is established.Finally,by describing the fault transfer process of the equal topological network nodes,combined with the two-state and three-state modeling methods of the functional state of the nodes,the fault transfer relationship between each node and the parent node is quantitatively described,and the conditional probability table of nodes is established to form a probabilistic network model for calculating the reliability of bus power supply.In order to improve the efficiency of modeling,an algorithm of process realization is designed to realize the automatic establishment of "system functional structure diagram-equal topological network" for the proposed method of establishing topological network and probabilistic network of aircraft power supply system.Firstly,the component input-output relationship description table is established according to the input stream and output stream of the component,and the topological network nodes are established according to the node modeling method;then the connection relationship matrix is generated according to the correlation between each node and its parent node,which realizes the automatic conversion of the functional structure diagram of the system to the functional equal topological network.Finally,the constructed network nodes are divided into three types:the root node,the intermediate node without the same name parent node and the intermediate node with the same name parent node.The conditional probability table of the three types of nodes is generated,and then the probabilistic network of the whole power system is obtained.In order to verify the effectiveness of the proposed method of reliability modeling and analysis for AEPS and its implementation algorithm,taking a large aircraft power supply system as an example,the equal topology network and probability network of the aircraft power supply system are established by using the proposed method,and the reliability calculation of the bus power supply in the aircraft power supply system is realized.The reliability calculation of the bus is carried out by writing the minimum path set algorithm.The calculation results verify the correctness of the reliability modeling and analysis method proposed in this paper.The established reliability analysis model can quickly and accurately calculate the power supply reliability of all bus in the aircraft power system.