SPEED PREDICTIVE CONTROL OF FIVE-PHASE PERMANENT MAGNET SYNCHRONOUS MOTOR WITH SINGLE-PHASE OPEN FAULT

When a single-phase open fault occurs in five-phase permanent magnet synchronous motor, there is a coupling term between the speed loop and the current loop. It is difficult to suppress the coupling term by using the predictive current control strategy with the conventional cascade structure, which results in speed and torque fluctuations and a reduction of anti-interference ability. Here, an integrated speed predictive control strategy combining speed loop with current loop is proposed to suppress the coupling term. When the motor is in fault of single-phase open, the mathematical model is derived by the coordinate transformation matrix in the alpha-beta coordinate. It is discretized into the speed predictive model by Taylor series. The fault-tolerant current is calculated by the constraint condition of the minimum stator copper loss. Moreover, the cost function is designed with the speed and current error term, and the optimal voltage vector is determined to switch the inverter by the minimum of the cost function among the all basic voltage vectors. The simulation results show that the proposed control strategy can reduce the errors in the speed and torque for the motor system and improve an anti-interference ability by comparing with the conventional strategy.