PREDICTIVE CONTROL-BASED OPEN-CIRCUIT FAULT DIAGNOSIS METHOD FOR MATRIX CONVERTER SWITCH

摘要

A predictive control-based open-circuit fault diagnosis method for matrix converter switch comprises the following steps: when a matrix converter functions normally, establishing a relationship model between an output voltage and an input voltage, and between an input current and a load current (S1); determining a count of combined switch states of the matrix converter (S2); establishing a state-space model to obtain predicted values of the load current, the input current and the input voltage in next sampling period (S3, S4); determining an evaluation function (S5); adopting, in each sampling period, a finite control set-model predictive control (FCS-MPC) strategy, to select, among the combined switch states, a switch state in which an evaluation function value is minimum as a switch state for a next sampling period (S6); establishing a state-space model to obtain a variation rule of a fault phase load current after occurrence of an open-circuit fault (S7); and performing online monitoring of the load current, and performing, according to the switch state selected by the FCS-MPC strategy, a fault diagnosis to identify a location of a breakdown switch (S8). The invention enables a diagnosis of an open-circuit fault in time.