Linear parameter varying sensorless torque control for singularly perturbed induction motor with torque and flux observers

Abstract

In this paper, a new approach being different from the concept of DTC and IFOC for a robust torque control design for induction motor is addressed. The design is based on the framework of singularly perturbed system theory and linear varying parameter systems. In these systems, the rotor flux is considered to be a time-varying parameter in order to guarantee a robust torque control with LPV flux observer with respect to the speed and resistance variations. In fact, this observer is designed to estimate the rotor flux as well as an MRAS observer is introduced to estimate the mechanical speed and rotor resistance. The main feature of this proposed structure is the enhancement of robustness with flux, speed and rotor resistance variation. This improvement leads to a considerable decrease of the torque ripples and ensures the stability for the entire operating range. The obtained simulations and experimental results are used to validate the effectiveness of the proposed control strategy. Keywords H ∞ LPV controller • Singularly perturbed system • LMI • MRAS observer • Induction motor Abbreviations Rotor speed (rd/s) ω s Stator current frequency (rd/s) ωr Induced rotor current frequency (rd/s) ωc Injected rotor current frequency (rd/s) J In Inertia f Coefficient of viscous C m Maximal electromagnetic torque ∼ Symbol indicating measured valuê Symbol indicating the estimated value B Sabir Ouchen

Review of speed estimation algorithms for three- phase induction motor

“…the procedure of rotor flux estimation is the essential component of a speed estimation scheme [ 33 , 66 , 71 , 72 ]. The procedures included in rotor speed estimation might be clarified into the following [73] : First, the rotor flux in the stationary frame of reference depending on the obtained voltages and currents of stator is estimated utilizing Eqs. (12) and (13) .…”