Search results for " induction"

MRAS Sensorless Techniques for High Performance Linear Induction Motor Drives.

2010

This paper proposes an MRAS (Model reference Adaptive System) speed observer suited for linear induction motors (LIM). Starting from the dynamical equation of the LIM in the synchronous reference frame in literature, the so-called voltage and current models of the LIM in the stationary reference frame, taking into consideration the end effects, have been deduced. These equations have been used respectively as reference and adaptive model of an MRAS observer. As machine under test, a complete dynamic model, based on the constructive elements of the LIM and taking into consideration the end effects by the definition of a proper air-gap function, has been adopted. This model has been previousl…

Innovative Observers for Induction Motor Control

In this thesis the problem of designing observers and controllers for induction motors has been studied and thoroughly discussed using tools from the nonlinear system theory, both for analysis and control purposes. Useful techniques have been used to identify the machine parameters off-line. In the Introduction was dealt the design a control system for a drive of asynchronous machines that uses a voltage source inverter to generate the currents and voltages which carry the drive by making use of an observer of the state rotor variables. The used control algorithms is the \textit{field oriented control} (FOC). The model of the asynchronous induction motor is described starting from the mecha…

Extracting Structured Knowledge From Sensor Data for Hybrid Simulation

2014

Obtaining continuous and detailed monitoring of indoor environments has today become viable, also thanks to the widespread availability of effective and flexible sensing technology; this paves the way for the design of practical Ambient Intelligence systems, and for their actual deployment in real-life contexts, which require advanced functionalities, such as for instance the automatic discovery of the activities carried on by users. Novel issues arise in this context; on one hand, it is important to reliably model the phenomena under observation even though, to this end, it is often necessary to craft a carefully designed prototype in order to test and fine-tune the theoretical models.

A Structural Approach to Infer Recurrent Relations in Data

2014

Extracting knowledge from a great amount of collected data has been a key problem in Artificial Intelligence during the last decades. In this context, the word "knowledge" refers to the non trivial new relations not easily deducible from the observation of the data. Several approaches have been used to accomplish this task, ranging from statistical to structural methods, often heavily dependent on the particular problem of interest. In this work we propose a system for knowledge extraction that exploits the power of an ontology approach. Ontology is used to describe, organise and discover new knowledge. To show the effectiveness of our system in extracting and generalising the knowledge emb…

State Space-Vector Model of Linear Induction Motors Including Iron Losses Part I: Theoretical Analysis

2018

This is the first part of a paper, divided into two parts, dealing with the definition of a space-vector dynamic model of the linear Induction motor (LIM) taking into consideration both the dynamic end-effects and the iron losses and its off-line identification. This first part specifically treats the theoretical formulation of this model, which has been expressed in a state form, so to be, in perspective, suitably adopted for developing novel non linear control techniques, non-linear observers as well as electrical losses minimization techniques (ELMTs). Besides the formulation of the dynamic model in space-vector state form, a steady-state analysis is proposed, highlighting the combined e…

State Space-Vector Model of Linear Induction Motors Including Iron Losses: Part II: Model Identification and Results

2018

This is the second part of a paper, divided into two parts, dealing with the definition of a space-vector dynamic model of the linear Induction motor (LIM) taking into consideration both the dynamic end-effects and the iron losses as well as the off-line identification of its parameters. The first part has treated the theoretical framework of the model. This second part is devoted to the description of an identification technique which has been suitably developed for the estimation of the parameters of the LIM dynamic model accounting for both the dynamic end-effects and iron losses, described in the first part of the paper. Such an identification technique is strictly related to the state …

Descriptor-type Kalman Filter and TLS EXIN Speed Estimate for Sensorless Control of a Linear Induction Motor.

2014

This paper proposes a speed observer for linear induction motors (LIMs), which is composed of two parts: 1) a linear Kalman filter (KF) for the online estimation of the inductor currents and induced part flux linkage components; and 2) a speed estimator based on the total least squares (TLS) EXIN neuron. The TLS estimator receives as inputs the state variables, estimated by the KF, and provides as output the LIM linear speed, which is fed back to the KF and the control system. The KF is based on the classic space-vector model of the rotating induction machine. The end effects of the LIMs have been considered an uncertainty treated by the KF. The TLS EXIN neuron has been used to compute, in …

Elasticity as a measure for online determination of remission points in ongoing epidemics.

2020

The correct identification of change-points during ongoing outbreak investigations of infectious diseases is a matter of paramount importance in epidemiology, with major implications for the management of health care resources, public health and, as the COVID-19 pandemic has shown, social live. Onsets, peaks, and inflexion points are some of them. An onset is the moment when the epidemic starts. A "peak" indicates a moment at which the incorporated values, both before and after, are lower: a maximum. The inflexion points identify moments in which the rate of growth of the incorporation of new cases changes intensity. In this study, after interpreting the concept of elasticity of a random va…

Synthesis and biological evaluation of 4-nitro-substituted 1, 3-diaryltriazenes as a novel class of potent antitumor agents

2011

Abstract We describe the synthesis and biological activity of a new class of 1,3-diaryltriazenes, namely 4-nitro-substituted 1,3-diaryltriazenes. Structure–activity relationship analysis reveals that 1,3-diaryltriazenes can be modified from inactive to highly cytotoxic compounds by the introduction of two nitro groups at the para positions of benzene rings and two additional electron-withdrawing groups (bromo, chloro, trifluoromethyl or fluoro substituents) at their ortho position. In order to increase the solubility of the modified compounds, we introduced various acyl groups to their triazene nitrogen. The results of LC-MS/MS analysis showed that N -acyltriazenes can be considered as prod…

Modular P-Chirogenic Aminophosphane-Phosphinite Ligands for Rh-Catalyzed Asymmetric Hydrogenation: A New Model for Prediction of Enantioselectivity

2007

An original series of P-chirogenic aminophosphane-phosphinite (AMPP) ligands has been synthesized from (+)- or(–)-ephedrine in 23 to 61 % overall yields by a versatile three-step methodology. The AMPP ligands, bearing either one or two P-chirogenic centers, were used in the form of rhodium complexes for the catalyzed hydrogenation of α-acetamidocinnamate as a test reaction. Notably, even with AMPP ligands all derived from (+)-ephedrine, variation of the substituent on a P-center allowed the phenylalanine derivatives to be obtained in either (S) or (R) absolute configurations, with ee values ranging from 99 % (S) to 88 % (R). The asymmetric induction was analyzed with the aid of X-ray struct…