Spectral Analysis for Detection of Two-switch Open-circuit Fault in Voltage Source Inverter of Induction Motor Drive

Two-level voltage source inverters are widely used in electric power drives where power switches play an important role, affecting the reliability of entire system. In the operation, these switches are affected by various factors that can lead to unexpected failures. The method based on Fourier spectrum analysis is a popular technique in which various signals including alternating current signals or magnetic field signals at the dc bus can be used for the feature extraction of the open-circuit fault. This paper presents the analytical calculation of the power transmitted through the inverter, thereby determining the harmonic components appearing in the power as well as the dc current at the dc bus. Fourier spectral analysis performed with this current signal enables the detection of twoswitch open-circuit faults in the inverter.