Fault diagnosis in variable speed drives by pattern recognition and probabilistic measures Conference Paper uri icon

abstract

  • In this work, the problem of fault detection and isolation in variable speed drives is addressed under open and closed-loop control. Open-switch faults in the power semiconductors are considered in this study. First, the resulting trajectories for the stator currents are analytically derived for single and double faults. This analysis motivates the proposed approach which is based on the resulting pattern of the stator currents in the dq-frame after a fault, where a histogram of the trajectory is calculated by dividing the plane in 24 equally spaced sectors. From the calculated histogram, a distinctive signature is associated to each fault trajectory in the dq-plane. Single and double faults in the power semiconductors are analyzed that all provide distinctive patterns for fault isolation. The proposed isolation methodology is independent of the load torque (system disturbance), supply frequency and only requires the information of the stator currents. Furthermore, since the isolation stage is focused on current trajectories in the dq-plane, open and closed-loop configurations of the variable speed drive can be simultaneously handled. Experimental results with 3/4 HP induction motor in both open and closed-loop operation validate the proposed methodology. © 2012 IFAC.

publication date

  • 2012-01-01