DSP Based Implementation of Multi Fault Signature Monitoring

The reference frame theory constitutes an essential aspect of electric machine analysis and control. In this study, apart from the conventional applications, it is reported that the reference frame theory approach (RFTA) can successfully be applied to real time fault diagnosis of electric machinery systems as a powerful tool to find the magnitude and phase quantities of fault signatures with good precision. Although it is possible to run RFTA for each fault signature consecutively, orthogonal PN (Pseudo Noise) code is proposed as an alternative method to detect more than one fault simultaneously. As the physical facts explaining the incipient fault mechanisms are studied for a long time, the motor fault signature frequencies and fault models are very well-known. Therefore, ignoring all other components, the proposed method focuses only on certain fault signatures in the current spectrum depending on the examined motor fault. Broken rotor bar and eccentricity faults are experimentally tested employing the TMS320F2812 digital signal processor (DSP) to prove the effectiveness of the proposed method. In this application, only the readily available drive hardware is used without employing additional components such as analog filters, signal conditioning board, external sensors, etc. The motor drive on-board DSP is utilized both for motor control and fault detection purposes providing instantaneous fault information. Being a model independent fault analyzer, this method can be applied to all multi-phase and single phase motors.