Sensorless closed loop V/f control of medium-voltage high-power induction motor with synchronized space vector PWM

This paper deals with sensorless constant v/f closed loop control of high-power induction motor with synchronized space vector pulse width modulation (SVPWM). The rotor speed is estimated based on the difference between the rotor flux speed expressed in stationary reference frame and slip speed. The estimated stator flux and the synchronous speed are used to generate the estimated back EMF. The difference between the reference voltage and the estimated back EMF voltage is used to generate the stator resistance voltage drop compensation required to maintain constant flux at low speed. Synchronized SVPWM technique is used in this closed loop drive. Synchronization guarantees elimination of sub-harmonics and reduces low order frequency harmonics. Thus, the proposed scheme guarantees high performance at high power levels. The simulation and experimental results are presented.