A Diagnostic Method for IGBTs Open-circuit Faults in NPC Inverter

This paper proposes an integration fault diagnosis approach of signal-driven method and data-driven method for three-level inverter feeding induction motor under open-loop v/f control. The current paths are analyzed under the normal case and open-circuit fault cases in the IGBTs. A method combining signal-driven and data-driven is proposed. The average values of the positive and negative currents and the ratios are used to be the input features of a two-layer feedforward neural network. Experiments are carried out at different speed and load conditions, which verify the effectiveness of the proposed method.