A Current Harmonic Monitoring-Based Online Condition Monitoring Method for SiC MOSFETs

Online condition monitoring method is very beneficial and critical to increase the reliability and life of silicon carbide metal-oxide-semiconductor field effect transistors and the inverter systems. This paper emphatically analyzes the influence of on-state resistance on the output nonlinearity of the inverter. A non-invasive online condition monitoring method based on current harmonic monitoring is proposed. The variation of the inverter output current Total Harmonic Distortion and the 5^th harmonic amplitude with the on-state resistance under different voltages and currents is monitored via MATLAB/Simulink simulation. The results show that this method is more suitable for low bus voltage and high current. And the amplitude of the 5^th harmonic increases by more than 30% when the on-state resistance increases by 1% under the condition of 100V and 12A. Moreover, simulation shows that the more the number of aging devices, the greater the change in the amplitude of the 5^th harmonic.