An MRAS Observer for Sensorless DFIM Drives With Direct Estimation of the Torque and Flux Rotor Current Components

Abstract

This paper proposes a model reference adjustable system observer for the sensorless control of doubly fed induction machines. The formulation is based on the direct calculation of the torque and flux rotor current components in the stator-flux-oriented coordinates by using the stator currents and voltages and the norm of the rotor current space vector. The tuning of the observer is discussed, and a theoretical sensitivity and stability analysis is performed in order to investigate the behavior of the observer under mismatched parameters. The paper is completed by the experimental validation of the observer performances

Online Estimation of the Rotor Flux Linkage and Voltage-Source Inverter Nonlinearity in Permanent Magnet Synchronous Machine Drives

“…Thus, the estimation of stator winding resistance should be together with or prior to the estimation of rotor flux linkage [10]- [17], [44]- [46]. Otherwise, the estimation will face the rank-deficient problem and the accuracy of the estimated rotor flux linkage will suffer from the mismatched stator winding resistance value used in the estimator [1].…”

A position-sensorless vector control of doubly-fed induction machines using adaptive reduced-order observers on holonomic reference frames

“…In contrast to [1] [5], the proposed scheme is straightforward; the estimated stator current can be calculated without stator flux computation beforehand. By comparison with [4], [7]- [8], the calculation is simply carried out with less parameters employment e.g. no need of core loss parameter.…”

“…Nevertheless, these observers require the stator flux infonnation, the common disadvantage is the DC-offset drift problem caused by the pure integral action of stator-flux calculation. In [4], the rotor current is selected as the error variable, and the estimated rotor flux is calculated through stator flux and torque calculations. This approach not only has the problem from drift problem caused by the stator flux calculation, but it also needs much more computation than necessary.…”

“…2) Real rotor speed requirement for the observer's feedback gains caused by inappropriate selection of reference frame for the model [5]. 3) Complexity of calculation [4] and more parameters requisition [7]- [8]. In this paper, novel rotor-position estimation methods are proposed.…”

A reduced-order observer based on stator flux estimation with straightforward parameter identification for sensorless control of DFIGs

“…Its main property is direct estimation of torque and rotor flux components. Additionally, sensitivity analysis and stability of the suggested method are presented in [8]. The presented algorithm in [9] is relatively simple, and it is not necessary to flux calculations.…”