张 倩,刘光斌

摘 要:介绍一种基于GFRF分析的非线性模拟电路故障诊断方法,着重阐述这种故障诊断技术中电路特征的提取方案,重点解决了激励信号的设计,Volterra频域核测量等关键技术问题。利用Volterra频域核辨识非线性系统,确定电路的最高显著阶,设计合适的激励信号,用范德蒙特方法分离出电路的各阶响应,利用公式计算出Volterra频域核。

关键词:非线性模拟电路;Volterra级数;GFRF;Volterra频域核测量;激励信号设计

中图分类号:TP273文献标识码:A

文章编号:1004-373X(2009)19-201-04

Feature Extraction for Nonlinear Analog Circuit Based on GFRF

ZHANG Qian,LIU Guangbin

(The Second Artillery Engineering College,Xi′an,710025,China)

Abstract:A fault diagnosis method for nonlinear analog circuit based on Generalized Frequency Response Function(GFRF) analysis is introduced.Especially,the project of feature extraction in circuit is expounded.The key technology such as designing the stimulus and Volterra frequency-domain kernels measurement are solved in this project.A nonlinear system is identified by applying Volterra frequency-domain kernel estimation.The highest significant order of nonlinear analog circuit is determined and the stimulus is designed.The response of each order is separated by the method of Vandermonele and the Volterra frequency-domain kernels is figured out by the formula.

Keywords:nonlinear analog circuit;Volterra series;GFRF;Volerra frequency-domain kernels measurement;design of stimulus

0 引 言

随着电子技术的飞速发展,非线性模拟电路在工程上广泛应用。但是,由于其自身的复杂性,使得电路的故障特征提取异常困难。选择恰当的电路模型并充分提取非线性电路特征是故障诊断的关键环节。由于非线性系统的Volterra1级数是系统的本质特征,Volterra核,特别是频域核具有鲜明的物理意义,且可进行工程上的频域分析,这对工程技术领域非常切合实际。它不仅提供了一种新的理论体系,而且为真正解决非线性实际问题提供了强有力的方法和工具[1]。在非线性电路故障诊断中,由于故障状态是系统传递特性出现非线性变化,故障的表现形式往往较复杂,从而限制了传统故障诊断方法的应用,然而基于频谱分析的故障诊断技术突破各种局限成为一种更有效的诊断方法。比较系统实际工作下的非线性频谱和处于正常状态及各种异常状态的标准频谱特征,根据误差大小判定非线性系统当前所处的状态。……