OPEN-CIRCUIT FAULT DIAGNOSIS IN VSI BY SIMPLE DIRECT CURRENT METHOD

Abstract

Failures in the Power device of inverter can be mainly divided as open circuit faults and short circuit faults. This type of failure will not necessarily cause the system shutdown and can remain undetected for an extended period of time. This can cause to another faults in the converter or in the remaining component, resulting total system shutdown and high repairing cost. For these reason, development of online methods that can detect open-circuit fault in voltage source inverter has become important. This paper focus on method of open-circuit fault diagnosis is current spectrum analysis technique which is based on the study of harmonic analysis of load current or output current of the inverter. Zero-order harmonics /DC component present in the signal when open-circuit fault occurs. The amplitude and the argument of each harmonics are used for open-circuit fault detection and localisation.