Sensorless field oriented control using common mode currents

A simple sensorless field oriented control technique of an induction motor drive is presented, that estimates the angular frequency of the main flux from common mode currents. The proposed technique is effective at any load level and any speed, ranging from zero to rated value and beyond, in the flux weakening region. Moreover, no motor parameter estimation procedures are required, neither additional sensors, nor the availability of the motor neutral point. The consistency of the proposed technique is practically evaluated by experimental results obtained on a standard induction motor drive