Modified speed sensorless indirect field-oriented control of induction motor using PLL

Abstract

This paper presents an improved method of rotor flux angle θs estimation for sensorless indirect oriented field control of induction motors based on a phase locked loop (PLL). A PLL is used to estimate the rotor flux angle taking account only the reference speed. The Extended Kalman Filter (EKF) is used to estimate speed and rotor flux. Extensive simulation and experimental tests confirm the effectiveness of the proposed approach.