Abstract—This paper describes a Adaptive Pseudoreduced-order Flux Observer (APFO) for speed control of the Induction Motor drive (IM) without a speed sensor. In this scheme an Adaptive Pseudo reduced-order Flux Observer (APFO) is used instead of the Adaptive Full-order Flux Observer (AFFO). In comparison with the AFFO, this method consumes less computational time, and provides a better speed estimation at very low speeds. APFO is used for estimate the IM rotor speed and stator resistance, and these are used as feedback signals for the Field Oriented Control (FOC), which is a widely used control method for Induction Motor drive (IM). Simulation results show that the estimated speed can replace to measured speed in sensorless induction motor drives, and also observed line currents, torque and speed under noload and load conditions. Experimental results are also shown for rotor estimated and real speed, speed in forward and reverse directions. This scheme is more efficient at very low speed.

Index Terms—Adaptive full-order flux observer (AFFO),adaptive pseudoreduced-order flux observer (APFO),induction motor drive (IM), model reference adaptive system(MRAS), speed estimation.

Raghu is with the department of electrical and electronics engineering, Anurag engineering college (Affiliated to JNT University), kodad, nalgonda (Dt.), Andhra pradesh, India (e-mail: raghu.thumu@gmail.com).
Srinivas Rao and Chandra Sekhar are with the department of electrical and electronics engineering, Anurag engineering college, kodad, nalgonda(Dt.), Andhra pradesh, India (e-mail: janigasrinivasrao@gmail.com,hod.eee@anurag.ac.in).

Cite: T. Raghu, J. Srinivas Rao, and S. Chandra Sekhar, "Simulation of Sensorless Speed Control of Induction Motor Using APFO Technique," International Journal of Computer and Electrical Engineering vol. 4, no. 4, pp. 440-444, 2012.