An advanced low-cost sensorless induction motor drive

An advanced solution for the implementation of sensorless vector control of induction motors is presented in the paper. The proposed system is based on new variables of an induction motor model. The system works using vector coordinates in a stationary /spl alpha//spl beta/ frame of reference. A phase locked loop was used to control the angle between the flux vector and stator current vector. The model variables and rotor velocity are calculated from simple equations based on steady state relationships for active and reactive powers. A current controller for a current regulated PWM (CRPWM) inverter based on the simplified load model is presented. The proposed controller is based on back-EMF calculation. The developed sensorless system was investigated both in simulations and experiments. The overall system was implemented using a simple ADMC330 microcontroller.