Reliability Study Of Brushless DC Motor Drive System

Due to the widely application of permanent magnetic materials andhigh-power electronic devices, brushless DC permanent magnet motor gets therapid development. It has now been used in industry, agriculture, aerospacemanufacturing and all areas of life. And the motor drive system workingenvironment is more and more bad, which will reduce reliability of motor drivesystem. In addition, the brushless DC motor drive system itself includes a seriesof electronic components. And the failure rate of electronic components willbecome subject to a variety of factors, which will reduce the efficiency of thesystem. Therefore, the brushless DC motor drive system for the reliability of thedesign is very important.This paper first describes some concepts and terminology of the reliability,mainly to lay the foundation for future reliability studies. Then the paper dividesthe whole system into two parts, separately establishing reliability model ofeach part, thereby establishing the reliability model of the whole system. Finallythis article obtains the mathematical model of the whole system.According to the reliability model, the paper analyzes the failure modesand failure mechanism of motor drive system, as well as drive system's faulttree analysis. First, the paper determines the failure mode of the system as wellas the reasons for the failure according to the FMEA, followed by theestablishment of a fault tree of a drive system. Through the fault tree the paperanalyzes reliability of drive system.On the basis of the establishment of the fault tree, the failure rate of thevarious components of the system is calculated. Then this paper gets thereliability index of the drive system. According to the proportion of the failurerate of each part, this article analyzes parts prone to failure of a motor drivesystem. This article is mainly to improve the failure rate in this part during thedesign process. Next, this paper establishes the reliability simulation model ofthe motor drive system, and obtains curve of reliability index. Finally, thisarticle uses a redundant design and derating reliability simulation design toimprove system reliability.