Contributions to the multi-frequency control of gridtied voltage source converters

El interés por la producción de energía limpia está en aumento y la generación de este tipo de energía se puede fomentar mediante la instalación de generadores locales. Dichos generadores son conectados a la red de distribución a través de convertidores de potencia. Al mismo tiempo el número de cargas conectadas a la red está incrementando y con ello el número de cargas no lineales. Estas últimas consumen corrientes armónicas y esto provoca distorsión armónica a la red. En esta tesis se estudia y se presentan contribuciones en el control de los convertidores de potencia para que al mismo tiempo que se inyecta potencia, el convertidor sea capaz de actuar adecuadamente frente a la distorsión armónica del voltaje de la red (control multifrecuencial). En primer lugar, esta tesis cubrirá el estudio de las diferentes técnicas de control de corrientes armónicas y también de las diferentes técnicas de sincronización y detección de componentes armónicas de tensión presentes en la red. En cuanto al cálculo de referencias de corrientes armónicas, se explican las principales variantes dependiendo de la funcionalidad deseada y se estudia la entrega de potencia instantánea constante incluso con red distorsionada. Además, se propone un nuevo método de cálculo para eliminar las principales oscilaciones de potencia sin exceder las limitaciones de distorsión de corrientes. También se describen las limitaciones del convertidor cuando se trabaja con componentes fundamentales y armónicas. Se analizan los principales saturadores multifrecuenciales para evitar la sobremodulación y se propone un nuevo saturador que no empeora la dinámica total del sistema y siempre consigue el mínimo THD de corriente. Por último, se aborda la problemática de la distorsión armónica del voltaje de red. Primero se estudia la compensación de las corrientes consumidas por cargas locales y después se propone la compensación directa de la tensión del PCC. En esta tesis se intenta incrementar el número de funcionalidades que puede desempeñar el convertidor para que además de entregar potencia, sea capaz de mejorar la calidad de la red, sin exceder las limitaciones físicas del convertidor. Cada una de las contribuciones es validada mediante resultados de simulación y experimentales

Reconfiguration Algorithm to Reduce Power Losses in Offshore HVDC Transmission Lines

The race to increase the efficiency and reduce the power losses in transmission systems has resulted in the substantial growth of high-voltage direct current (HVDC) transmission systems. Moreover, the interconnection of these transmission systems significantly increases their reliability. However, the control of these meshed grids is a key problem that usually is managed through the control of the VSCs in those grids, but the control of the VSC can be complemented with a reconfiguration algorithm. This paper proposes the use of the particle swarm optimization algorithm, in order to reconfigure meshed HVDC transmission systems and reduce losses. The proposed algorithm has been tested in the CIGRE benchmark grid, which comprises of several offshore wind farms that generate energy sent to the grid through several HVDC transmission lines. The results show that as the energy generation changes due to wind changes, the grid topology must be reconfigured in order to achieve the maximum efficiency. Doing this reconfiguration, power savings around 18–19% could be achieve

How relevant is the place where first-year college students live in relation to the increase in body mass index?

Producción Científica1) Objective: This study analyzes the evolution of the body mass index (BMI) throughout the academic year associated with changes in the lifestyle associated with the place where students live during the course, lifestyle design, and health strategies for the university community. (2) Methods: A total of 93 first-year nursing students participated in this study. Data were collected throughout the course by administering self-reported questionnaires about eating habits and lifestyles, weight, and height to calculate their BMI and place of residence throughout the course. Data were analyzed using statistical analysis (Mann–Whitney, chi-square, Student’s t-test, repeated-measures analysis of variance, and least significant difference tests). (3) Results: We found that the mean BMI increases significantly throughout the course among all students regardless of sex, age, eating habits, or where they live during the course. At the beginning of the course, the mean BMI was 22.10 ± 3.64. The mean difference between the beginning of the course and the middle has a value of p-value < 0.015 and between the middle of the course and the end a p-value < 0.009. The group that increased the most is found among students who continue to live in the family nucleus rather than those who live alone or in residence. Students significantly changed their eating and health habits, especially those who live alone or in residence. (4) Conclusions: There is an increase in BMI among students. It is necessary to carry out seminars or talks that can help students understand the importance of good eating practices and healthy habits to maintain their weight and, therefore, their health, in the short, medium, and long term and acquire a good quality of life.Este trabajo fue apoyado por subvenciones (Grants 2019-GRIN-26896, 2020-GRIN-29192

Tocilizumab in visual involvement of giant cell arteritis: a multicenter study of 471 patients

Background: Visual involvement is the most feared complication of giant cell arteritis (GCA). Information on the efficacy of tocilizumab (TCZ) for this complication is scarce and controversial. Objective: We assessed a wide series of GCA treated with TCZ, to evaluate its role in the prevention of new visual complications and its efficacy when this manifestation was already present before the initiation of TCZ. Design: This is an observational multicenter study of patients with GCA treated with TCZ. Methods: Patients were divided into two subgroups according to the presence or absence of visual involvement before TCZ onset. Visual manifestations were classified into the following categories: transient visual loss (TVL), permanent visual loss (PVL), diplopia, and blurred vision. Results: Four hundred seventy-one GCA patients (mean age, 74 +/- 9 years) were treated with TCZ. Visual manifestations were observed in 122 cases (26%), of which 81 were present at TCZ onset: PVL (n = 60; unilateral/bilateral: 48/12), TVL (n = 17; unilateral/bilateral: 11/6), diplopia (n = 2), and blurred vision (n = 2). None of the patients without previous visual involvement or with TVL had new episodes after initiation of TCZ, while only 11 out of 60 (18%) patients with PVL experienced some improvement. The two patients with diplopia and one of the two patients with blurred vision improved. Conclusion: TCZ may have a protective effect against the development of visual complications or new episodes of TVL in GCA. However, once PVL was established, only a few patients improved

The presence of both HLA-DRB1[*]04:01 and HLA-B[*]15:01 increases the susceptibility to cranial and extracranial giant cell arteritis.

Objectives: To determine if patients with the predominant extracranial large-vessel-vasculitis (LVV) pattern of giant cell arteritis (GCA) have a distinctive HLA-B association, different from that reported in biopsy-proven cranial GCA patients. In a further step we assessed if the combination of HLA-B and HLA-DRB1 alleles confers an increased risk for GCA susceptibility, either for the cranial and extracranial LVV phenotypes. Methods: A total of 184 patients with biopsy-proven cranial GCA, 105 with LVV-GCA and 486 healthy controls were included in our study. We compared HLA-B phenotype frequencies between the three groups. Results: HLA-B*15 phenotype was significantly increased in patients with classic cranial GCA compared to controls (14.7% versus 5.8%, respectively; p<0.01; OR [95% CI] =2.81 [1.54-5.11]). It was mainly due to the HLA-B*15:01 allele (12.5% versus 4.0%, respectively; p<0.01; OR [95% CI] =3.51 [1.77-6.99]) and remained statistically significant after Bonferroni correction. Similar HLA-B*15 association was observed in patients with the LVV-GCA (11.4% versus 5.8%, p=0.04, OR [95% CI] =2.11 [1.04-4.30]). This association was also mainly due to the HLA-B*15:01 allele (10.5% versus 4.0%, respectively; p=0.0054; OR [95% CI] =2.88 [1.19-6.59]). Noteworthy, the presence of HLA-B*15:01 together with HLA-DRB1*04:01 led to an increased risk of developing both cranial and extracranial LVV-GCA. Conclusions: Susceptibility to GCA is strongly related to the HLA region, regardless of the clinical phenotype of expression of the disease.This work was partially supported by RETICS Programs, RD08/0075 (RIER), RD12/0009/0013 and RD16/0012 from ‘‘Instituto de Salud Carlos III’’ (ISCIII) (Spain). However, this research did not receive any specific grant from funding agencies in the commercial or not-for-profit sectors

HLA association with the susceptibility to anti-synthetase syndrome

Objective: To investigate the human leukocyte antigen (HLA) association with anti-synthetase syndrome (ASSD). Methods: We conducted the largest immunogenetic HLA-DRB1 and HLA-B study to date in a homogeneous cohort of 168 Caucasian patients with ASSD and 486 ethnically matched healthy controls by sequencing-based-typing. Results: A statistically significant increase of HLA-DRB1*03:01 and HLA-B*08:01 alleles in patients with ASSD compared to healthy controls was disclosed (26.2% versus 12.2%, P=1.56E-09, odds ratio-OR [95% confidence interval-CI]=2.54 [1.84-3.50] and 21.4% versus 5.5%, P=18.95E-18, OR [95% CI]=4.73 [3.18-7.05]; respectively). Additionally, HLA-DRB1*07:01 allele was significantly decreased in patients with ASSD compared to controls (9.2% versus 17.5%, P=0.0003, OR [95% CI]=0.48 [0.31-0.72]). Moreover, a statistically significant increase of HLA-DRB1*03:01 allele in anti-Jo-1 positive compared to anti-Jo-1 negative patients with ASSD was observed (31.8% versus 15.5%, P=0.001, OR [95% CI]=2.54 [1.39-4.81]). Similar findings were observed when HLA carrier frequencies were assessed. The HLA-DRB1*03:01 association with anti-Jo-1 was unrelated to smoking history. No HLA differences in patients with ASSD stratified according to the presence/absence of the most representative non-anti-Jo-1 anti-synthetase autoantibodies (anti-PL-12 and anti-PL-7), arthritis, myositis or interstitial lung disease were observed. Conclusions: Our results support the association of the HLA complex with the susceptibility to ASSD

Trajectory planning for the IRB120 robotic arm using ROS

Este proyecto usa el entorno ROS(Robot Operating System) para desarrollar el control del brazo robot IRB 120. Se explicará la creación del modelo del robot, la planificación de trayectorias y la comunicación con dicho robot. Además se incluirá la percepción con un sensor Kinect y algunas aplicaciones como la evitación de obstaculos y el seguimiento de objetos.This project uses the ROS (Robot Operating System) framework for developing the control of the IRB 120 robotic arm. It explains the creation of the robot model, path planning and communication with the robot. It also includes the perception with a Kinect sensor and applications, such as, obstacles avoidance and following an object.Grado en Ingeniería en Electrónica y Automática Industria

Trajectory planning for the IRB120 robotic arm using ROS

Este proyecto usa el entorno ROS(Robot Operating System) para desarrollar el control del brazo robot IRB 120. Se explicará la creación del modelo del robot, la planificación de trayectorias y la comunicación con dicho robot. Además se incluirá la percepción con un sensor Kinect y algunas aplicaciones como la evitación de obstaculos y el seguimiento de objetos.This project uses the ROS (Robot Operating System) framework for developing the control of the IRB 120 robotic arm. It explains the creation of the robot model, path planning and communication with the robot. It also includes the perception with a Kinect sensor and applications, such as, obstacles avoidance and following an object.Grado en Ingeniería en Electrónica y Automática Industria

Detección de fallos en el equipamiento de medida en los centros de transformación

En los últimos años, a los centros de transformación se les está proporcionando un equipamiento que\ud permite la gestión completa del mismo. De este modo, de producirse medidas erróneas podría ser muy\ud perjudicial para el normal funcionamiento del centro.\ud En este trabajo, empleando las técnicas de predicción de carga que permiten estimar cual será la carga\ud eléctrica en el futuro, será posible detectar dos errores sistemáticos de medidas diferentes.\ud Para la predicción de carga, se utilizará una red neuronal y el análisis de componentes principales\ud será empleado para comprimir la información.\ud Finalmente, el sistema desarrollado será probado con datos obtenidos del simulador implementado\ud por un distribuidor eléctrico y datos reales proporcionados por una compañía eléctrica.In recent years, Secondary Transformer Substations are being provided with equipment to allow the\ud full management of the substation. In this way, erroneous measurements could be very harmful for the\ud normal performance of the substation.\ud In this work, employing Short Term Load Forecasting (STLF) which allows to estimate what the\ud future electric load will be, it is possible to detect two different systematic measurements errors. For the\ud load forecasting, the chosen system is composed by an artificial neural network and principal component\ud analysis is employed for information compression.\ud Finally, developed system is tested with simulated data obtained from a simulator provided by a\ud Transmission System Operator and real data provided by an Electrical Company. Different levels of gain\ud and offset errors are detected.Master Universitario en Ingeniería Industria

A New Approach to Detection of Systematic Errors in Secondary Substation Monitoring Equipment Based on Short Term Load Forecasting

In recent years, Secondary Substations (SSs) are being provided with equipment that allows their full management. This is particularly useful not only for monitoring and planning purposes but also for detecting erroneous measurements, which could negatively affect the performance of the SS. On the other hand, load forecasting is extremely important since they help electricity companies to make crucial decisions regarding purchasing and generating electric power, load switching, and infrastructure development. In this regard, Short Term Load Forecasting (STLF) allows the electric power load to be predicted over an interval ranging from one hour to one week. However, important issues concerning error detection by employing STLF has not been specifically addressed until now. This paper proposes a novel STLF-based approach to the detection of gain and offset errors introduced by the measurement equipment. The implemented system has been tested against real power load data provided by electricity suppliers. Different gain and offset error levels are successfully detected