| CPC G01R 31/40 (2013.01) [G01R 19/1659 (2013.01)] | 10 Claims |

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1. An open-circuit fault diagnosis method for a silicon (Si)/silicon carbide (SiC) hybrid H-bridge inverter power device, comprising the following steps:
S1, injecting a first switching sequence into a second driving mode of the power device at intervals of a preset period, wherein the second driving mode comprises a SiC metal-oxide-semiconductor field effect transistor (MOSFET) first-on and then-off mode;
S2, collecting inverter data and calculating an output voltage residual to obtain a first output voltage residual; determining whether the first output voltage residual enters a voltage threshold diagnosis region, and obtaining a first fault flag; proceeding to step S3 when the first output voltage residual enters the voltage threshold diagnosis region, or, proceeding to step S4 when the first output voltage residual is outside the voltage threshold diagnosis region;
S3, injecting the first switching sequence into an all-driving mode of the power device, collecting inverter data again and calculating an output voltage residual to obtain a second output voltage residual; determining whether the second output voltage residual enters the voltage threshold diagnosis region, and obtaining a second fault flag;
S4, collecting inverter data and calculating an inductor current pulsation value to obtain a first inductor current pulsation value; and determining whether the first inductor current pulsation value pulsates within an inductor current pulsation region, and obtaining a third fault flag; and
S5, performing open-circuit fault diagnosis on the power device based on the first fault flag, the second fault flag, and the third fault flag.
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