Research Of Technology And Reliability Of Airplane DC Bus Power Control Unit

DCBPCU (Direct Current Bus Power Control Unit) is the centre of airplane's automatic power distribution system. Its strong abilities to supervise and control the system are realized in this paper basically, and the promotion of its reliability is discussed further.The improvement of its fault tolerant technique from similar dual-redundancy to dissimiliar dual-redundancy is introduced primarily. Realtime backup technique is adopted in the dual-redundancy system, and mutual diagnosis adding third party diagnosis is adopted in the fault diagnosis system. The improvement composed of hardware and softeware. From the hardware side, the totally same structure of CPU control board is changed into different structure; and from the software side, the totally same language of process is changed into different language. The purpose of this improvement is to eliminate the DCBPCU system's collapse which caused of generic fault. The function of whole control system, the structure of hardware and the process of software are introduced in this paper to explain how to realize the key technique.Then, the reliability of DCBPCU system is discussed numerically based on Bayesian Theory. Combined with traditional fault tree analysis, the DCBPCU's fault module is established to analyze single integrate circuit's influence to whole control system. The function relationship between MTBF and fault probability is given in this paper, and provide a kind of method for analysis of the automatic power distribution system's reliability.Finally,in order to improve the communication reliability of this control system, optical fiber communication is discussed. In this paper, the basical theory of optical fiber communication, and the components selection of circuit modules which composed of single receiver and single transmitter are introduced.