A Novel E/F Contoller for Squirrel Cage Induction Motor Based on Rotor Flux Orientation

In this paper, a novel E/F controller is proposed for three phase squirrel cage induction machine based on its rotor flux oriented model. The proposed controller is intended for a current sensor-less induction motor drive operating with speed feedback and it offers an attractive solution to various problems associated with the conventional V/F type of controller. The speed control loop of the proposed controller emulates the back emf of the motor and not the terminal voltage and therefore, the reduction in magnetizing flux in the low speed region is overcome. In addition, the zero speed operation becomes feasible in the proposed E/F controller which is difficult to realize in case of conventional V/F controller. Moreover, since the proposed controller is based on the rotor flux oriented model of the motor, it gives a performance which is on par with a vector controlled drive and the control algorithm is simplified to a greater extent. The proposed controller is validated through simulation. To highlight its performance, it is also compared with conventional vector drive.