Model prediction-based three-phase inverter fault online diagnosis method

The present invention relates to a model prediction-based three-phase inverter fault online diagnosis method. According to the method, an inverter system reference model of closed-loop control is built; the prediction values of the model are compared with actual observation values, so that the residuals of state variables are obtained; the relationships of the residuals and threshold values are analyzed; whether an open-circuit fault has occurred is judged, an alarm is given, and a fault diagnosis instrument is started; the fault diagnosis instrument is an on-line diagnosis mechanism which is built according to preset fault conditions; and the fault diagnosis instrument evaluates the values of state variables which are abnormal currently, selects a fault state which is closest to an actual state and accurately positions a fault switching device. The model prediction-based three-phase inverter fault diagnosis method of the invention has the advantages of few input quantities, high real-time performance, no nee