Flux-Angle Identification Using Test Signals for Field Oriented Control of Induction Motor without Speed Sensor at Very Low Stator Frequency

摘要

The field oriented control of induction motor drives without speed sensor requires the calculation of the flux angle and the speed by a model from stator voltages and currents. In case of faulty estimation of the flux angle, i.e. due to incorrect model parameters, the stability of the system is at risk. A method is proposed to identify and correct a wrong flux angle in the model even at zero hertz stator frequency. Thus stable operation of the sensorless controlled drive can be ensured in the entire torque-speed plane.