Sensorless Direct Field-Oriented Control of Three-Phase Induction Motor Drives for Low-Cost Applications

A sensorless direct rotor field-oriented control (SDRFOC) scheme of three-phase induction motors for low-cost applications is presented in this paper. The SDRFOC algorithm is based on a sensorless closed-loop rotor flux observer whose main advantages are simplicity and robustness to motor parameter detuning. The whole algorithm has been developed and implemented on a low-cost fixed-point digital signal processor controller. Experimental results are presented for a 0.5-kW induction motor drive for a primary vacuum pump used in industry applications.