Faults detection and diagnosis of multilevel inverter based on signal processing

Abstract

An open fault detection and analysis method for Multilevel Inverter based on Signal Processing is proposed in this paper. A reconfiguration method is also discussed. The output voltage is used as a diagnostic signal to detect the fault types and locations. In this paper, characteristics of open transistor faults in Multilevel Inverter (cascaded H-bridge seven-level) three-phase PWM-controlled shunt active power filter are determined. Phase currents cannot be trusted as fault indicator, like done in many research works in this field, since their waveforms change slightly in the presence of open transistor fault. The proposed method uses H bridges output voltages to determine the faulty phase, the faulty bridge and more precisely, the open fault transistor. The expected and simulation results are in good agreement with each other, which represents the proposed method can perform satisfactorily to detect the fault types and locations.