微弱信号检测的3种非线性方法

阐述了随机共振法、混沌振子法及差分振子法3种方法的基本监测思想,确定了数学模型。随机共振系统(SR)是一个非线性双稳态系统,存在着在某一最佳输入噪声强度下,使系统产生最高信噪比输出,达到抑制噪声、放大微弱信号的目的。SR系统数学模型可由非线性Langevin方程定义,并进行了分析及仿真。混沌系统具有对初值敏感性及对噪声免疫的特点,数学模型选用Holmes型Duffing方程为监测器,进行了分析及仿真。差分振子法是基于差分方程构造监测器,以二维离散性系统作为数学模型,进行了分析及仿真。将3种方法应用于同步发电机转子匝间短路故障监测和异步电动机转子断条故障监测的实例中是成功的,证明了3种方法的有效性和准确性。

Three nonlinear methods of weak signal detection

The basic concepts of three detection methods of stochastic resonance,chaos resonator and differential resonator are described and their mathematical models are established. Stochastic resonance is a nonlinear bi - stable system,which produces the highest signal - to - noise ratio output for the best noise intensity input to suppress noise and amplify weak signal. Its mathematical model can be defined by nonlinear Langevin equation. Chaotic system is sensitive to initial values and immune to noise,which adopts Holmes - Duffing equations as its mathematical monitor model. Diffe - rential resonator is based on the monitor constructed by differential equations,which takes two - dimensional discrete system as its mathematical model. Analysis and simulations are carried out. Three methods are successfully applied to the monitoring of the inter - turn short - circuit fault of synchronous motor and the rotor - bar break fault of asynchronous motor,which shows their validities.