Luenberger Research Articles

Stator and Rotor Faults Monitoring of the Inverter-Fed Induction Motor Drive using State Estimators

The paper deals with the application of the Extended Kalman Filter and the Extended Luenberger Observer algorithms for the stator and rotor fault detection of the induction motor fed by PWM inverter. The induction motor conditions are analyzed using estimated rotor and stator-winding resistance. Mathematical models of the extended state estimators are presented, in which the stator and rotor resistances are added as additional electromagnetic state variables. Experimental results for the inverter-fed induction motor, with shorted stator-turns and broken rotor bars, are presented and analysed.

Sensorless Direct Torque Control of Induction Machine Using Luenberger Observer and Simplified Extended Kalman Filter

A comparison between the sensorless Direct Torque Control (DTC) of the induction machine, based on different observers is proposed in this paper. The two DTC systems adopt alternatively a simplified extended Kalman filter and the Luenberger observer in order to estimate the speed of the induction machine and other quantities. PI regulator is used to regulate the estimate speed and improve the performances of the whole system. Simulation results show that the ripples of both torque and flux are reduced remarkable and a good dynamic of the speed and torque are achieved.

The Luenberger indicator and directions of measurement: a bottoms-up approach with an empirical illustration to German savings banks

The Luenberger productivity indicator applies directional distance functions which allow to specifying in what direction (i.e. direction of measurement) the operating units will be evaluated. In the presence of a change in the direction of measurement, the standard components of the existing Luenberger productivity indicator may provide values which are not compatible with reality. In order to eliminate this pitfall, the so-called bottoms-up approach is used to revisit the definition of the indicator and its components. We start with a list of selected sources of productivity change, namely efficiency change, technical change and direction change, then examine the best possible way of measuring each of the sources and combine them to derive a new measure of productivity change. The proposed indicator will be illustrated by means of an empirical application to a panel of 417 German saving banks over the time period 2006-2012. The example explains how the proposed approach is able to properly measure efficiency change, technical change and direction change. The results also provide conclusive evidence about the effect of the change in direction of measurement on the results of the productivity over time in a centralized management scenario.

Speed Estimation by Using EKF Techniques for Sensor-Less DTC of PMSM with Load Torque Observer

This paper proposes a Direct Torque Control (DTC) of a Permanent Magnet Synchronous Motor (PMSM) without mechanical speed and position sensors. These later are estimated by using the Extended Kalman Filter (EKF) only by measurement of the stator line voltages and currents. Moreover, DTC uses no current controller and no motor parameters other than the stator resistance, which yields a faster torque response and lower parameter dependence than with others motor control techniques. The Kalman filter is an observer for linear and non-linear systems. Also, due to an angle modification scheme with error tracking, the Sensor-less drive system is robust to parameter variations. A load torque can also be estimated by using Luenberger Observer. A simulation model is developed in MATLAB/SIMULINK and is used to verify the basic operation (performance) of the Sensor-less DTC of PMSM

A New Sensorless Control Design of Induction Motor Based on Backstepping Sliding Mode Approach

In this paper, we propose a new sensorless control of induction motor (IM). The design of this control is based on backstepping and sliding mode approaches. First, the backstepping control is designed to steer the flux and speed variables to theirs references and to compensate the uncertainties trough appropriate Lyapunov functions. Second, sliding mode controllers (SMC) is used for stator currents control. Finally, we estimate the rotor speed by using the Luenberger observer (LO) and the rotor flux by using the extended Kalman filter (EKF). Simulation results are illustrated and prove the effectiveness of the proposed sensorless control in different working of speed references and against load torque disturbance

Fault Detection and Control loop reconfiguration for WECS with PMSG speed sensor fault

This paper describes a fault tolerant controller (FTC) design to enhance the wind energy conversion system (WECS) with Permanent Magnet Synchronous Generator (PMSG) robustness to mechanical rotor speed sensor failure. This proposed sensor FTC strategy is based on the combination of the actual sensor and an adaptive Luenberger observer with a decision-making unit, which detects whether the mechanical sensor is faulty and selects the most accurate generator rotor speed and position for the Indirect Field Oriented control (IFOC) loops. Extensive simulation study shows that the proposed sensor FTC approach can efficiently detect the generator speed sensor fault and tolerate this type of fault, and so offers a simple configuration with a satisfactory accurate reference-rotor-speed tracking requirement for maximum power extraction.

A Luenberger state observer for stator resistance estimation in sensorless induction motor drives

The primary objective of this paper is to elimination of the problem of sensitivity to parameter variation of induction motor drive. The proposed sensorless strategy is based on an algorithm permitting a better simultaneous estimation of the rotor speed and the stator resistance including an adaptive mechanism based on the lyaponov theory. To study the reliability and the robustness of the sensorless technique to abnormal operations, some simulation tests have been performed under several cases. The proposed sensorless vector control scheme showed a good performance behavior in the transient and steady states, with an excellent disturbance rejection of the load torque. © 2013 Praise Worthy Prize S.r.l. - All rights reserved.

System observability and the Luenberger identity observer

System observability and the Luenberger identity observer

An efficient algorithm for calculation of the Luenberger canonical form

An efficient algorithm for calculation of the Luenberger canonical form