Sensorless Slip Frequency Estimation of Induction Motor in the Very Low Speed Region

Abstract

A simple slip frequency estimation algorithm without a speed or position sensor is proposed, especially aimed at the very low rotor speed estimation. The stator flux is obtained by the simple digital integration from the compensated voltage reference. And the rotor speed is estimated from the slip frequency estimation algorithm, which is useful under any control such as the vector control, the decoupling control, and the slip frequency control. A rotor speed estimation as low as 5 [rpm] is verified through the experiments combined with the voltage command type vector control and the proposed slip frequency estimation algorithm. © 1996, The Institute of Electrical Engineers of Japan. All rights reserved.