FAULT DIAGNOSING METHOD BASED ON STANDARD DEVIATION OF DETAIL COEFFICIENTS FOR POWER CONVERTER OF SWITCHED RELUCTANCE MOTOR

摘要

A fault diagnosing method based on standard deviation of detail coefficients for the power converter of a switched reluctance motor, operates by detecting the transient value of phase current in the power converter of a switched reluctance motor, the standard deviation of detail coefficients a is calculated and is taken as a fault characteristic quantity, and then whether there is a short circuit fault in the main switch of the power converter of the switched reluctance motor is diagnosed with a curve of standard deviation of detail coefficients a of phase current in the power converter of the switched reluctance motor in the entire range of rotation speed or in the entire range of torque. The method is applicable to the power converter of a switched reluctance motor with any topological structure, with any number of phases, can diagnose short circuit faults accurately, and has a great value in engineering application.

主权项

1. A fault diagnosing method based on standard deviation of detail coefficients for the power converter of a switched reluctance motor, comprising:
detecting the transient value of phase current f(t) in the power converter of a switched reluctance motor; and, with the following expression:σ=1k(dj,k-dj,k_)2 calculating the standard deviation of detail coefficients σ, wherein, the real values of detail coefficients are dj,k=∫Rf(t)2−j/2φ(2−jt−k)dt, the mean values of detail coefficients aredj,k_=1k∑kdj,k,t is time variable, j is resolution level, k is discretized translation value, φ(2−jt−k) is the conjugate complex of wavelet function φ(2−jt−k), and R is the integral range of time, carrying out a transformation for the transient value of phase current f(t) as follows:f(t)=∑j=1∑kcj,k2-j/2ϕ(2-jt-k)+∑j=1∑kdj,k2-j/2φ(2-jt-k),wherein, the scale factor is cj,k=∫Rf(t)2−j/2φ(2−jt−k)dt, and φ(2−jt−k) is the conjugate complex of scale function φ(2−jt−k); taking the standard deviation of detail coefficients a as a fault characteristic quantity to diagnose whether there is any short circuit fault in the main circuit of the power converter of the switched reluctance motor;
wherein if the curve of standard deviation of detail coefficients σ in the entire range of rotation speed fluctuates between 0.005 and 0.01 or if the curve of standard deviation of detail coefficients σ in the entire range of torque fluctuates near 0.005, it indicates that a short circuit fault has occurred in the power converter of the switched reluctance motor.