Multiple open-circuit fault diagnosis in voltage-fed PWM motor drives using the current Park´s Vector phase and the currents polarity

Presently, condition monitoring and fault diagnostics in electric drives are already considered essential to optimize maintenance operations and increase reliability levels. Regarding fault-tolerant inverters, it is well known that reliable fault diagnostic methods are mandatory to trigger remedial actions. This paper presents a diagnostic method for multiple open-circuit faults in pulse-width-modulation (PWM) voltage source inverters (VSI) feeding ac motors, with a special focus on the issue of false alarms during transients, such as load or speed changes. The diagnostic method combines a detection method based on derivative of the current Park´s Vector phase, which guarantees robustness to transients, with a localization method based on the currents polarity, which allows for multiple faults diagnosis. In order to prove the reliability and effectiveness of the proposed fault diagnostic method, several simulation and experimental results are presented, using a permanent magnet synchronous motor (PMSM) drive.