Técnicas de detección y diagnóstico de fallos en motores de inducción alimentados por inversor en estado transitorio

El equipamiento industrial se encuentra sujeto a esfuerzos. Si se produce cierta combinación de estos o algún esfuerzo superase el umbral de diseño, puede producir fallo prematuro, con los consiguientes costes asociados. Uno de los elementos más importantes en la industria es el motor de inducción. Se puede alimentar directamente de red en aplicaciones de velocidad fija o a través de inversor en aplicaciones de velocidad variable o que requieran control del par, como es el caso en el que se centra esta tesis. Este motor puede sufrir fallos antes del final de su vida útil. Existe la necesidad de técnicas adecuadas para identificar fallos en motores de inducción alimentados por inversor en estados transitorios. Aquí se encuadra el desarrollo de esta tesis, con el objetivo de desarrollar una nueva técnica, la Transformada Dragón, basada en átomos tiempo-frecuencia, que permite solventar los problemas de resolución que aparecen en otras técnicasDepartamento de Ingeniería EléctricaDoctorado en Ingeniería Industria

Detection of Broken Rotor Bars in Nonlinear Startups of Inverter-Fed Induction Motors

[EN] Fault detection in induction motors powered by inverters operating in nonstationary regimes remains a challenge. The trajectory in the time-frequency plane of harmonics related to broken rotor bar develops very in proximity to the path described by the fundamental component. In addition, their energy is much lower than the amplitude of the first harmonic. These two characteristics make it challenging to observe them. The Dragon Transform (DT), here presented, is developed to overcome the described problem. In this article, the DT is assessed with nonlinear inverter-fed startups, where its high time and frequency resolutions facilitate the monitoring of fault harmonics even with highly adjacent trajectories to the first harmonic path.Fernández-Cavero, V.; Pons Llinares, J.; Duque-Perez, O.; Morinigo-Sotelo, D. (2021). Detection of Broken Rotor Bars in Nonlinear Startups of Inverter-Fed Induction Motors. IEEE Transactions on Industry Applications. 57(3):2559-2568. https://doi.org/10.1109/TIA.2021.30663172559256857

Development and validation of a nomogram to predict kidney survival at baseline in patients with C3 glomerulopathy

Background C3 glomerulopathy is a rare and heterogeneous complement-driven disease. It is often challenging to accurately predict in clinical practice the individual kidney prognosis at baseline. We herein sought to develop and validate a prognostic nomogram to predict long-term kidney survival. Methods We conducted a retrospective, multicenter observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. The dataset was randomly divided into a training group (n = 87) and a validation group (n = 28). The least absolute shrinkage and selection operator (LASSO) regression was used to screen the main predictors of kidney outcome and to build the nomogram. The accuracy of the nomogram was assessed by discrimination and risk calibration in the training and validation sets. Results The study group comprised 115 patients, of whom 46 (40%) reached kidney failure in a median follow-up of 49 months (range 24?112). No significant differences were observed in baseline estimated glomerular filtration rate (eGFR), proteinuria or total chronicity score of kidney biopsies, between patients in the training versus those in the validation set. The selected variables by LASSO were eGFR, proteinuria and total chronicity score. Based on a Cox model, a nomogram was developed for the prediction of kidney survival at 1, 2, 5 and 10 years from diagnosis. The C-index of the nomogram was 0.860 (95% confidence interval 0.834?0.887) and calibration plots showed optimal agreement between predicted and observed outcomes. Conclusions We constructed and validated a practical nomogram with good discrimination and calibration to predict the risk of kidney failure in C3 glomerulopathy patients at 1, 2, 5 and 10 years.ACKNOWLEDGEMENTS: Work on this study was supported by the Instituto de Salud Carlos III / Fondo Europeo de Desarrollo Regional (ISCIII/FEDER; grants PI16/01685 and PI19/1624) and Red de Investigación Renal (RD12/0021/0029; to M.P.) and the Autonomous Region of Madrid (S2017/BMD-3673; to M.P.). S.R.d.C. is supported by the Ministerio de Economia y Competitividad (grant PID2019-104912RB-I00) and the Autonomous Region of Madrid (grant S2017/BMD-3673). None of the funders had any role in the study design, data collection, analyses, reporting or decision to submit for publication

Development and validation of a nomogram to predict kidney survival at baseline in patients with C3 glomerulopathy

10 p.-4 fig.-2 tab. 1 graph. abst.Background: C3 glomerulopathy is a rare and heterogeneous complement-driven disease. It is often challenging to accurately predict in clinical practice the individual kidney prognosis at baseline. We herein sought to develop and validate a prognostic nomogram to predict long-term kidney survival.Methods: We conducted a retrospective, multicenter observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. The dataset was randomly divided into a training group (n = 87) and a validation group (n = 28). The least absolute shrinkage and selection operator (LASSO) regression was used to screen the main predictors of kidney outcome and to build the nomogram. The accuracy of the nomogram was assessed by discrimination and risk calibration in the training and validation sets.Results: The study group comprised 115 patients, of whom 46 (40%) reached kidney failure in a median follow-up of 49 months (range 24–112). No significant differences were observed in baseline estimated glomerular filtration rate (eGFR), proteinuria or total chronicity score of kidney biopsies, between patients in the training versus those in the validation set. The selected variables by LASSO were eGFR, proteinuria and total chronicity score. Based on a Cox model, a nomogram was developed for the prediction of kidney survival at 1, 2, 5 and 10 years from diagnosis. The C-index of the nomogram was 0.860 (95% confidence interval 0.834–0.887) and calibration plots showed optimal agreement between predicted and observed outcomes.Conclusions: We constructed and validated a practical nomogram with good discrimination and calibration to predict the risk of kidney failure in C3 glomerulopathy patients at 1, 2, 5 and 10 years.Work on this study was supported by the Instituto de Salud Carlos III / Fondo Europeo de Desarrollo Regional (ISCIII/FEDER; grants PI16/01685 and PI19/1624) and Red de Investigación Renal (RD12/0021/0029; to M.P.) and the Autonomous Region of Madrid (S2017/BMD-3673; to M.P.). S.R.d.C. is supported by the Ministerio de Economia y Competitividad (grant PID2019-104912RB-I00) and the Autonomous Region of Madrid (grant S2017/BMD-3673).Peer reviewe

Spectral analysis of stationary and transient signals for the monitoring of electrical machines

This video tutorial was prepared for the 13th Edition of the IEEE International Symposion on Diagnostics for Electrica Machines (SDEMPED 2021). The use of electric machines is not only widespread in the industry, they are also used in railway traction, electric vehicles, wind power generation, to name a few sectors. Adequate condition monitoring of these machines helps to detect failures at an early stage. This prevents these incidents from evolving into catastrophic failures, which saves on maintenance and operating costs, protects companies' investments, and therefore helps their competitiveness and quality of service. Monitoring methods can be based on spectral analysis of variables such as electric current, vibrations, flux, speed or sound. Obtaining quality signatures related to the machine condition must be based on a correct spectral analysis, taking into account concepts such as spectral resolution or spectral leakage. Moreover, in many of these applications, the machine's operation is not stationary, which requires the use of advanced time-frequency analysis tools. This tutorial aims to provide a useful practice guide for a correct spectral analysis of stationary and transient signals – this will permit a correct fault detection and severity quantification, which are essential for the diagnosis of electrical machines – and to present to the audience those areas of research where the presenters believe there are still open problems to be solved. The analysis of non-stationary signals will also be covered, providing an overview of the most advanced techniques, such as those based on time-frequency atoms correlation. There are a wide range of available techniques but the signal analysis results are conditioned by their time and frequency resolution capabilities. This tutorial overviews the basic concepts of spectral analysis of both stationary and transient signals and how these affect the spectra quality, which in the end also affects the motor diagnosis. The tutorial also covers advanced topics such as speed estimation, tools for transient analysis, and an introduction to time-frequency atoms.There is also a part imminently practical that illustrates real cases of stationary and transient induction motor fault detection using the techniques and concepts described during the tutorial

Early Detection of Broken Rotor Bars in Inverter-Fed Induction Motors Using Speed Analysis of Startup Transients

Producción CientíficaThe fault diagnosis of electrical machines during startup transients has received increasing attention regarding the possibility of detecting faults early. Induction motors are no exception, and motor current signature analysis has become one of the most popular techniques for determining the condition of various motor components. However, in the case of inverter powered systems, the condition of a motor is difficult to determine from the stator current because fault signatures could overlap with other signatures produced by the inverter, low-slip operation, load oscillations, and other non-stationary conditions. This paper presents a speed signature analysis methodology for a reliable broken rotor bar diagnosis in inverter-fed induction motors. The proposed fault detection is based on tracking the speed fault signature in the time-frequency domain. As a result, different fault severity levels and load oscillations can be identified. The promising results show that this technique can be a good complement to the classic analysis of current signature analysis and reveals a high potential to overcome some of its drawbacks.Mexican Council of Science and Technology (CONACYT) by the scholarship 48705

Detection and quantification of bar breakage harmonics evolutions in inverter-fed motors through the dragon transform

Producción CientíficaThe problem of detecting and quantifying bar breakage harmonics in inverter-fed induction motors has not been solved by the time–frequency transforms present in the technical literature. The paper proposes a new transform, called dragon transform, to solve this problem. The dragon atoms are defined with shapes perfectly adapted to the harmonic trajectories in the time–frequency plane, no matter how complex they are, enabling the precise tracing of the harmonics to be detected. A quantification method is also proposed, which obtains for the first time in the technical literature, the time evolutions of the harmonic amplitudes during a complex transient such as the start-up and the steady state of an inverter-fed motor. The transform performance is validated testing the induction motor under different load levels

Clinical profiles and patterns of kidney disease progression in C3 glomerulopathy

Background: C3 glomerulopathy is a rare kidney disease, which makes it difficult to collect large cohorts of patients to better understand its variability. The aims of this study were to describe the clinical profiles and patterns of progression of kidney disease. Methods: This was a retrospective, observational cohort study. Patients diagnosed with C3 glomerulopathy between 1995 and 2020 were enrolled. Study population was divided into clinical profiles by combining the following predictors: eGFR under/above 30 ml/min per 1.73 m2, proteinuria under/above 3.5 g/d, and histologic chronicity score under/above 4. The change in eGFR and proteinuria over time was evaluated in a subgroup with consecutive measurements of eGFR and proteinuria. Results: One hundred and fifteen patients with a median age of 30 years (interquartile range 19-50) were included. Patients were divided into eight clinical profiles. Kidney survival was significantly higher in patients with a chronicity score <4 and proteinuria <3.5 g/d, both in those presenting with an eGFR under/above 30 ml/min per 1.73 m2. The median eGFR slope of patients who reached kidney failure was -6.5 ml/min per 1.73 m2 per year (interquartile range -1.6 to -17). Patients who showed a reduction in proteinuria over time did not reach kidney failure. On the basis of the rate of eGFR decline, patients were classified as faster eGFR decline (≥5 ml/min per 1.73 m2 per year), slower (<5 ml/min per 1.73 m2 per year), and those without decline. A faster eGFR decline was associated with higher probability of kidney failure. Conclusions: Kidney survival is significantly higher in patients with a chronicity score <4 and proteinuria <3.5 g/d regardless of baseline eGFR, and a faster rate of decline in eGFR is associated with higher probability of kidney failure.Funding: Analyses in this publication were conducted through a research collaboration with Novartis Pharma AG, who provided funding and also provided input to the analysis protocol. Work in this study was supported by the Instituto de Salud Carlos III/Fondo Europeo de Desarrollo Regional (ISCIII/FEDER) grant PI16/ 01685 and PI19/1624, and Red de Investigación Renal (RedInRen) (RD12/0021/0029) (to MP), the Autonomous Region of Madrid (S2017/BMD-3673) (to MP). SRdeC is supported by Ministerio de Economia y Competitividad grant PID2019-104912RB-I00 y Autonomous Region of Madrid grant S2017/BMD-367

Clinical Profiles and Patterns of Kidney Disease Progression in C3 Glomerulopathy

C3 glomerulopathy is a rare kidney disease, which makes it difficult to collect large cohorts of patients to better understand its variability. The aims of this study were to describe the clinical profiles and patterns of progression of kidney disease. This was a retrospective, observational cohort study. Patients diagnosed with C3 glomerulopathy between 1995 and 2020 were enrolled. Study population was divided into clinical profiles by combining the following predictors: eGFR under/above 30 ml/min per 1.73 m 2, proteinuria under/above 3.5 g/d, and histologic chronicity score under/above 4. The change in eGFR and proteinuria over time was evaluated in a subgroup with consecutive measurements of eGFR and proteinuria. One hundred and fifteen patients with a median age of 30 years (interquartile range 19-50) were included. Patients were divided into eight clinical profiles. Kidney survival was significantly higher in patients with a chronicity score <4 and proteinuria <3.5 g/d, both in those presenting with an eGFR under/above 30 ml/min per 1.73 m 2. The median eGFR slope of patients who reached kidney failure was −6.5 ml/min per 1.73 m 2 per year (interquartile range −1.6 to −17). Patients who showed a reduction in proteinuria over time did not reach kidney failure. On the basis of the rate of eGFR decline, patients were classified as faster eGFR decline (≥5 ml/min per 1.73 m 2 per year), slower (<5 ml/min per 1.73 m 2 per year), and those without decline. A faster eGFR decline was associated with higher probability of kidney failure. Kidney survival is significantly higher in patients with a chronicity score <4 and proteinuria <3.5 g/d regardless of baseline eGFR, and a faster rate of decline in eGFR is associated with higher probability of kidney failure

Mycophenolate Mofetil in C3 Glomerulopathy and Pathogenic Drivers of the Disease

12 p.-4 fig.-4 tab.BACKGROUND AND OBJECTIVES: C3 glomerulopathy is a complement-mediated disease arising from abnormalities in complement genes and/or antibodies against complement components. Previous studies showed that treatment with corticosteroids plus mycophenolate mofetil (MMF) was associated with improved outcomes, although the genetic profile of these patients was not systematically analyzed. This study aims to analyze the main determinants of disease progression and response to this therapeutic regimen.DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We conducted a retrospective, multicenter, observational cohort study in 35 nephrology departments belonging to the Spanish Group for the Study of Glomerular Diseases. Patients diagnosed with C3 glomerulopathy (n=81) or dense deposit disease (n=16) between January 1995 and March 2018 were enrolled. Multivariable and propensity score matching analyses were used to evaluate the association of clinical and genetic factors with response to treatment with corticosteroids and MMF as measured by proportion of patients with disease remission and kidney survival (status free of kidney failure).RESULTS: The study group comprised 97 patients (84% C3 glomerulopathy, 16% dense deposit disease). Forty-two patients were treated with corticosteroids plus MMF, and this treatment was associated with a higher rate of remission and lower probability of kidney failure (79% and 14%, respectively) compared with patients treated with other immunosuppressives (24% and 59%, respectively), or ecluzimab (33% and 67%, respectively), or conservative management (18% and 65%, respectively). The therapeutic superiority of corticosteroids plus MMF was observed both in patients with complement abnormalities and with autoantibodies. However, patients with pathogenic variants in complement genes only achieved partial remission, whereas complete remissions were common among patients with autoantibody-mediated forms. The main determinant of no remission was baseline proteinuria. Relapses occurred after treatment discontinuation in 33% of the patients who had achieved remission with corticosteroids plus MMF, and a longer treatment length of MMF was associated with a lower risk of relapse.CONCLUSIONS: The beneficial response to corticosteroids plus MMF treatment in C3 glomerulopathy appears independent of the pathogenic drivers analyzed in this study.Work in this study was supported by the Instituto de Salud CarlosIII/ Fondo Europeo de Desarrollo Regional (ISCIII/FEDER) grant PI16/01685 and Red de Investigación Renal (RedInRen) (RD12/0021/0029) (to M. Praga), and the Autonomous Region of Madrid (S2017/BMD-3673) (to S. Rodríguez de Córdoba and M. Praga).E. Goicoechea de Jorge is supported by the Spanish “Ministerio de Ciencia, Innovación y Universidades” (RYC-2013-13395 and RTI2018-095955-B-100). S. Rodríguez de Córdoba is supported by Ministerio de Economía y Competitividad/FEDER grant SAF2015-66287R and Autonomous Region of Madrid grant S2017/BMD3673.Peer reviewe