Online diagnosis of multiple-switch simultaneous faults in SRM drives based on current errors

This article presents a new online diagnostic technique for multiple power switch faults in switched reluctance motor (SRM) drives. Unlike the existing schemes, nearly all potential failure scenarios in the power switches of the standard asymmetric half-bridge (AHB) converter are considered in this work. First, a new current sensing scheme is proposed without modifying the standard AHB structure and the obtained current errors for current control of the drive system are analyzed for fault diagnosis. Second, a new fault variable is extracted from the dc-bus current, and subtests are introduced to detect and locate the failure of multiple switches in a phase-leg with the same or hybrid faults. Diagnosis of multiswitch faults in the same or different phases is achieved within a few sampling periods. The diagnostic capability of the proposed methods is thoroughly validated through experimental studies using a three-phase 12/8-pole SRM drive system.