A Fast Average Model-based Method for IGBT and Current Sensor Fault Diagnosis in Grid-Tied Inverters

This paper presents an average model-based diagnosis method for current sensor fault and IGBT open-circuit fault in grid-tied three-phase voltage-source inverters (VSIs). The diagnosis algorithm is based on observed inductor current sum deviation and bridge arm line voltage residuals with adaptive thresholds. The proposed method can guarantee fast diagnosis speed as well as strong robustness for both current sensor faults and IGBT faults, without extra hardware circuits. The fault diagnosis speed can be as fast as one switching period. No tuning effort is needed under different operating conditions since all the diagnosis calculation errors are covered in the thresholds. Finally, experiments are carried out to prove the effectiveness.