A New Detection Method Based On Duffing Oscillator Array For Broken Rotor Bars In Induction Motors

Asynchronous motor is an important rotating machine widely used in industrial system. With the rapid development of the modern industrial system, the capacity of a single motor is keeping increasing and the load is also becoming more complicated now. A motor failure can not only result in damage to the motor, but also can result in unscheduled machine downtime and the shutdown of a production line ,which will cause heavy financial losses and catastrophic failure. The rotor broken bar fault, is one of the most familiar faults for induction motors .Consequently ,researches on rotor broken bar fault diagnosis able to detect this kind of fault at an early stage are of great theoretical significance and socioeconomic benefits.Incipient rotor bar breaking fault detection is a problem of detecting weak signal in heavy noise. Duffing oscillators' phase transformation from chaos to intermittent chaos is sensitive to the signals, whose frequency difference is little different from the reference signal, while it is immune to white noise and the signals, whose frequency is quite different from the reference signal. Thus, the performance is the detection sensitivity and anti-interference capability.A new method is proposed on the basis of the traditional Hilbert modulus. This technique gets rid of the interference of the fundamental frequency by using the Hilbert transform, The principle of DC elimination, which is available for an arbitrary signal with random non-integral periods, is proposed by the double Hilbert transformation. And the characteristic fault frequency can be detected basing on Duffing oscillator array. The fault of the rotor broken bars can be identified and diagnosed through distinguishing the periodic intermittent chaos of the pair of oscillators and it is very valid for detecting fault of the rotor broking bars at an early stage. During detecting of rotor faults, the results are usually affected by load oscillation, in this paper a new method based on Wavelet Transform to solve the problem is proposed. It differs conspicuously load oscillation from broken rotor bar faults and enhances the credibility of detection.A large number of simulating and experimental results show that it is an effective method, thanks to its processing, which is very simple without dealing with signals in advance, and it will have a bright prospect.