Sensorless Control Strategy for Multiphase Induction Motor with Stator and Rotor Resistance Identification Based on Injecting Third Harmonic Current

It is no longer a problem to operate an induction machine stably with sensorless control, but it is a new challenge to make induction motor system high performance without speed sensor. This paper focus on high performance sensorless control strategy with parameters identification for multiphase induction machines. This method firstly has the advantage of sensorless algorithm. Secondly, accurate rotor magnetic field orientation because of rotor resistance estimation online improves the dynamic performance of the motor and reduces the loss. Additionally, precise rotor resistance, which supplied by third harmonic plane, can increase the stability of system at low speed and negative speed. It is noted that injection of 3rd harmonic current not only would not bring extra torque ripple, but also can increase torque density of the motor. Finally, to validate the feasibility of proposed method, simulation results by using Matlab/Simulink are shown in the paper.