A Diagnosis Method of Inverter Open-Circuit Fault Based on Interval Sliding Mode Observer

This study proposes a method for identifying open-circuit faults in inverters using an interval sliding mode observer. The direction of current flow via the switch sets the mixed logic dynamic (MLD) model for the inverter in both normal and fault conditions. The current estimators of the upper bound sliding mode observer and the lower bound sliding mode observer are added together and weighted to construct a current interval sliding mode observer. Then, the designed observer is used to estimate the inverter's standard three-phase current. By comparing the currents recorded by the present system and the observer, the current residual can be used to discover open-circuit problems. Using the data included in the residual, a table is constructed that can be used for fault localization. The designed current interval sliding mode observer increases the robustness of fault diagnostic scheme, accelerates the convergence of interval observer, and effectively decreases chattering.