Sensorless Stator Flux Oriented Control of IMs using a new Delayed-State KF-based Algorithm

This paper proposes a new reduced delayed-state Kalman filter (DSKF) based algorithm to realize the speed-sensorless vector control of induction motor. This algorithm estimates the stator flux components in the stationary reference frame, using the derivatives of the stator flux components as mathematical model and the stator voltage equations as observation model. The DSKF-based algorithm accurately estimates the stator flux components in transient operations because the derivative of the absolute stator flux value is taken into account as a forcing term in the mathematical model, so that applications both in flux rising operations and in field weakening region are possible. The estimated stator flux components are used for stator field orientation control (SFOC) without rotor speed sensor. Experiments show that the sensorless control scheme using the new DSKF-based algorithm requires a low computational effort, is stable and effective also at low speeds.