飞机变速恒频电源系统可靠性的Monte-Carlo分析

随着电力电子技术的发展,用静止变换器取代机械式的恒速传动装置成为可能,因而出现了变速恒频电源系统。在变速恒频电源系统中,发电机是直接由飞机发动机来传动的。由于发动机的转速不是恒定的,因而发电机输出的交流电的频率也是变化的,故再用变换器把变频交流电变换为恒频交流电。飞机变速恒频电源系统的主要部件有无刷交流变频发电机、变换器和控制器。 一般情况下,变换器和控制器主要由电子元器件组成,其失效参数服从指数分布。但是发电机的失效参数为正态分布,因此,其可靠性的分析研究,用一般的解析方法是困难的。本文分析了飞机变速恒频电源系统的可靠性模型。应用Monte-Carlo方法对某型号飞机变速恒频电源系统方案的可靠性指标(R(t),MTBF)进行了数字仿真,得到了各主要部件的工作模式重要度,为该系统的研制设计提供了理论基础。

Monte-Carlo Analysis of Reliability of Aircraft Variable Speed Constant Frequency (VSCF) Electrical Power System

The development of the technology of power electronics make the power system possible to replace a mechanic constant speed device by a static converter, consequently, there is a new kind of VSCF electrical power system in which the generator is directly driven by the aircraft motor appearing in recent years. As the speed of the motor is not constant, the frequency of an AC set driven by a generator is also variable, then, the converter is utilized to turn the variable frequencies of the AC set into constant ones. The main parts of the aircraft VSCF electrical power system consist of the no-brush AC variable frequency generator, converter and controller.Generally, the converter and controller are mainly composed of electronic elements. The failure parameter obeys the exponent distribution rule. However, the failure parameter of the generator follows the Gauss distribution, therefore, the analytical study of its reliability is difficult to carry on with the common analytical method. This paper focuses on the analysis of the reliability model of the aircraft's VSCF electrical power system. The Monte-Carlo method is applied in digital simulation to the reliability index of a certain-type of aircraft VSCF electrical power sytem, and thus the degree of importance of the working model in every main part is obtained to provide a theoretical basis for the development and design of this system.