Predictive current control implementation in the sensorless induction motor drive

A speed sensorless control system for an induction motor with predictive current controller is presented. The whole control does not require measurements of the motor speed and motor flux. A closed loop observer system with robustness against parameters variation is used for the control approach. The proposed observer computes the required state variables correctly in wide frequency range. In the system predictive current controller based on the computation of back electromagnetic force by the observer is implemented. In case of motor choke use, the choke parameters are added to predictive current controller algorithm. It is shown that the choke inductance has to be taken into account in predictive controller. The whole proposed control idea makes the system practically insensitive to the changes of motor parameters, even at very low frequency. It is proved that the drive system is applicable to the high dynamic performance and wide range of rotor speed. The description of test bench is included. The obtained simulation and experimental results confirm the good properties of the proposed speed sensorless induction motor drive.