Speed and stator resistance identification schemes for a low speed sensorless induction motor drive

Online Stator and Rotor Resistance Estimation Scheme Using Sliding Mode Observer for Indirect Vector Controlled Speed Sensorless Induction Motor

“…The authors in [8,[15][16][17] proposed that the actual and estimated rotor fluxs are the same, hence the error equation 14is as follows:…”

“…It is clear that when this parameters varies, decoupling between the flux and torque components of stator currents is lost and hence the operational performance of the machine deteriorates. However, when a very high accuracy is desired, the performance of speed estimation is not good particularly at low speeds, [7,8,9]. To solve this problem, this paper proposes a method for both rotor speed identification with stator and rotor resistance estimation in sensorless induction motor drives based on sliding mode observer.…”

Stator Resistance Estimation for Speed Sensorless Vector Controlled Induction Motor Drives as Influenced by Saturation

“…In such method, the stator resistance adaptation mechanism is determined with the difference between the measured and observed stator currents. In [2], speed estimation with stator resistance algorithm based on a sliding mode current observer which combines variable structure control, Lyapunov stability and Popov's hyper stability theories are used. All of these methods assumed that there is no change in the magnetizing inductance during the stator resistance estimation.…”

“…So, the interest in stator resistance adaptation appeared recently, with the advances of speed sensorless systems [2]. An accurate value of the stator resistance is of crucial importance for correct operation of a sensorless drive in the low speed region, since any mismatch between the actual value and the set value used within the model of speed estimation may lead not only to a substantial speed estimation error but to instability as well [6]- [7].…”