A Half-Bridge-Level Gate-Oxide Failure Online Detection Method Without Invading Converters for SiC MOSFETs

Half-bridge-level gate-oxide failure online detection is a basis of low failure rates for power converters with silicon carbide (SiC) metal–oxide–semiconductor field-effect transistors (MOSFETs). The conventional detection methods of gate-oxide failure usually invade gate driver boards or alter the control strategies of power converters. A simple detection method of half-bridge-level gate-oxide failure is proposed by connecting half-bridge SiC MOSFETs and gate driver boards through the proposed circuit. The principles of the proposed circuit are solving the difference between two ON-state gate voltages in high-side (HS) and low-side (LS) SiC MOSFETs and solving the difference between an ON-state gate voltage of LS SiC MOSFETs and a positive output voltage of LS gate driver board. As a result, if either of the two absolute difference values is more than 10 mV, the gate-oxide of half-bridge modules will be detected as a failure. The half-bridge modules with gate-oxide failure can be replaced. The proposed circuit is validated by a case study on a single-phase half-bridge inverter. The proposed circuit does not invade gate driver boards and change the control strategies of power converters. It can detect half-bridge gate-oxide failure caused by various working conditions.