Effects of Mismatched Parameters in MRAS Sensorless Doubly Fed Induction Machine Drives

Abstract

This paper deals with a performance analysis of sensorless drives based on doubly fed induction machines. A simplified model of the whole system equipped with a generic MRAS observer is introduced, by taking also into account a mismatch in the parameters. Three MRAS known in literature are analyzed into detail and meaningful analytic relations between the mismatched parameters and the error in the estimated rotor position during a steady state operation are deduced. Then, a stability analysis is performed and the stability regions of each drive are found. Finally, the theoretical results are experimentally validated

Sensorless Control of Brushless Doubly Fed Induction Machine Using a Control Winding Current MRAS Observer

“…DFIG, previous studies have investigated several model reference adaptive system (MRAS) observer based methods, evolving around error variables such as stator/rotor currents along with stator/rotor flux, making them suitable for stand-alone and grid-connected operations [9]- [11]. The effects of mismatched parameters on the performances of sensorless control of DFIGs based on MRAS observers are analyzed in [12], while an adaptive tuning of the stator inductance in a rotor current-based MRAS observer is introduced in [13]. With respect to the BDFRG, the sensorless operation using model-based methods are presented in [14].…”

“…Since it is assumed that the current converges to a steady-state solution, according to (11) and (12), the relationship between the PW current, CW current and rotor current in the general synchronously rotating d-q reference frame is given by i  and k  : (a) 0 A, (b) 14 A, and (c) 28 A.…”

A critical review on the grid integration issues of DFIG based wind farms

“…The effect of stator resistance on the magnitude and phase angle of the resultant optimal rotor excitation voltage is examined in [22]. A simplified model to evaluate the error in the estimated rotor position and to perform a local stability analysis of a system is discussed in [23]. An analysis of sub synchronous resonance in series compensated DFIG based wind farm is reported in [24].…”

MRAS observers for Doubly-Fed Induction Machine in wind energy conversion systems

“…The aim of sensorless algorithms is to provide a speed estimate using a kind of speed observer. The advantages of sensorless techniques include improved system reliability, robustness and reduction in cost [3]. The Model Reference Adaptive System (MRAS) is a model-based sensorless technique which can be implemented on most vector controlled DFIM setups without the need for additional hardware.…”