Lead pursuit control of multiphase drives

Los accionamientos multifásicos, compuestos por una máquina eléctrica de más de tres fases alimentada por un convertidor de potencia, han atraído recientemente un importante interés en la comunidad investigadora debido a las ventajas que presentan frente a las máquinas trifásicas convencionales. Este es el caso de la mejor distribución de potencia por fase, la menor producción de armónicos en el convertidor de potencia y, la más importante, la tolerancia a fallos, lo cual significa que la máquina multifásica puede seguir funcionando cuando una o varias fases se pierden, siempre que el número restante de fases sea igual o mayor que tres. Debido a esta alta fiabilidad, los accionamientos multifásicos son especialmente adecuados para aplicaciones relacionadas con los vehículos eléctricos (terrestres, marítimos y aéreos) y las energías renovables por razones de seguridad y/o económicas. El uso de controladores avanzados y de alto rendimiento en accionamientos multifásicos es particularmente relevante, ya que las estrategias de control convencionalmente aplicadas a los accionamientos trifásicos no terminan de alcanzar un estándar en su extensión al caso multifásico. La razón es la mayor complejidad y número de variables a controlar. En este contexto, los controladores predictivos han encontrado un interesante nicho de aplicación en convertidores de potencia y accionamientos multifásicos debido a su formulación intuitiva y flexible: un modelo del sistema es usado para calcular las predicciones de las variables controladas, que luego se comparan con las referencias impuestas dentro de una función de coste. Esta estrategia permite incorporar varios objetivos de control y restricciones en el proceso de control a través de la función de coste. Sin embargo, es bien sabido que este tipo de controlador sufre de un alto coste computacional y contenido armónico de corriente que limita su aplicación en los accionamientos multifásicos. La investigación desarrollada en esta Tesis se centra en la mitigación de las limitaciones citadas siguiendo dos objetivos principales: • La incorporación de observadores de corrientes rotóricas en el controlador predictivo para mejorar así la precisión del modelo predictivo y, consecuentemente, el rendimiento del sistema de control, principalmente en términos de contenido armónico y pérdidas por conmutación en el convertidor de potencia. Un observador de Luenberger es construido para este propósito utilizando una estrategia innovadora de posicionamiento de polos en su diseño. • La introducción de un grado de libertad adicional en el controlador predictivo basado en tiempos de muestreo variables e implementado usando el concepto de lead pursuit. El resultado es un controlador novedoso que conduce a una resolución en los tiempos de conmutación más fina en comparación con las técnicas predictivas más convencionales, lo que proporciona una reducción importante en el contenido armónico. Las estrategias de control propuestas son validadas mediante simulación y experimentación utilizando un accionamiento compuesto por una máquina de inducción de cinco fases como caso de ejemplo. Los resultados y conclusiones derivadas de esta investigación han sido presentados en cinco trabajos principales publicados en revistas internacionales de alto impacto, los cuales constituyen las contribuciones de esta Tesis por compendio de artículos. Sin embargo, otros trabajos relacionados con la línea de investigación han sido también publicados en artículos de revista y conferencia y en un capítulo de libro.Multiphase drives, constituted by an electric machine with more than three phases fed by a power converter, have recently attracted an important interest in the research community due to the advantages that they present over the conventional three-phase ones. This is the case of the better power distribution per phase, the lower harmonic production in the power converter, and the most important one, the fault-tolerant capability, which means that the multiphase machine can still be operated when one or several phases are missing, provided that the number of remaining phases is equal or greater than three. Due to this high reliability, multiphase drives are specially well suited for applications related to electric vehicles (terrestrial, maritime and aerial) and renewable energies for safety and/or economical reasons. The use of advanced and high-performance controllers in multiphase drives is particularly relevant, since the control strategies conventionally applied to three-phase drives do not reach a standard in their extension to the multiphase case. The reason is the greater complexity and number of variables that must be controlled. In this context, predictive controllers have found an interesting niche of application in power converters and multiphase drives due to their intuitive and flexible formulation: a model of the system is used to compute predictions of the controlled variables, which are later compared with the imposed references in a cost function. This strategy permits incorporating several control objectives and constraints in the control process through the cost function. However, it is well known that this type of controller suffers from a high computational cost and current harmonic content that limit its application in multiphase drives. The research developed in this Thesis work is focused on the mitigation of the cited limitations following two main goals: • The incorporation of rotor current observers in the predictive controller in order to improve the accuracy of the predictive model and, consequently, the control system performance, principally in terms of harmonic content and commutation losses in the power converter. A Luenberger observer is constructed for that purpose using an innovative pole-placement strategy in its design. • The introduction of an additional degree of freedom in the predictive controller based on variable sampling times and implemented using the lead-pursuit concept. The result is a novel controller that leads to a finer resolution in the commuting times in comparison with more conventional predictive techniques, which provides an important reduction in the harmonic content. The proposed control strategies are validated by simulation and experimentation using a five-phase induction machine drive as case example. The results and conclusions derived from this research have been presented in five main works published in high-impact international journals, which constitute the contributions of this article compendium Thesis. Nevertheless, other related works have also been published in journal and conference papers and a book chapter

Min-Max Predictive Control of a Five-Phase Induction Machine

In this paper, a fuzzy-logic based operator is used instead of a traditional cost function for the predictive stator current control of a five-phase induction machine (IM). The min-max operator is explored for the first time as an alternative to the traditional loss function. With this proposal, the selection of voltage vectors does not need weighting factors that are normally used within the loss function and require a cumbersome procedure to tune. In order to cope with conflicting criteria, the proposal uses a decision function that compares predicted errors in the torque producing subspace and in the x-y subspace. Simulations and experimental results are provided, showing how the proposal compares with the traditional method of fixed tuning for predictive stator current control.Ministerio de Economía y Competitividad DPI 2016-76493-C3-1-R y 2014/425Unión Europea DPI 2016-76493-C3-1-R y 2014/425Universidad de Sevilla DPI 2016-76493-C3-1-R y 2014/42

Patients Discharged with Home Enteral Nutrition from a Third-Level Hospital in 2018

Patients who, during admission, begin to use enteral nutrition (EN) and do not recover adequate oral intake need proper planning prior to discharge. The present study is a descriptive analysis of patients discharged with EN from our hospital in 2018. In all, the study included 141 patients (50.3% male) with an average age of 76.18 14 years with the most frequent reasons for enteral support being neurological disease (71.3%) and ear, nose, and throat (ENT) and maxillofacial surgery (17.02%) (others accounted for 11.68%). In these two groups, di erences were observed in both the average age (77 vs. 70.5 years) and sex of patients—mostly women (58%) in the first group and men (70%) in the second. Overall, the access routes used were nasogastric tube (76.4%), and percutaneous endoscopic gastrostomy (18.4%); 67.1% of the episodes ended by 30 June, 60.6% of patients died (47% of neurological patients), and 39.3% patients recovered function of the oral passage (85% of surgical/head and neck tumor). The duration of support was as follows: 1–3 months, 32%; 6–12 months, 26.9%; more than 12 months, 18.5%. This indicated some frequent and clearly di erentiated profiles in the patients studied, which may contribute to better care and support in order to maintain long-term treatment

Online Adaptive Set of Virtual Voltage Vectors for Stator Current Regulation of a Six-Phase Induction Machine Using Finite State Model Predictive Controllers

(This article belongs to the Special Issue Electric Power Applications II) // "This article is an open access article distributed under the terms and conditions of the Creative Commons ttribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/"Virtual voltage vectors (VVV) have been used for the control of multi-phase induction machines, where different sub-spaces appear related to the torque production and losses generation. In the literature, several sets of VVV have been used, aiming at reducing harmonic content while maintaining a low computational burden. This paper proposes the use of different sets of VVV to regulate the stator current of multi-phase drives using finite-state model predictive controllers. In the proposal, only one set is active at each control period. This active set is obtained through a preliminary analysis using performance maps. As a result, a method is derived for the online selection using the current operating point. The selection is based on a simple computation from variables usually measured on variable-speed drives. Results are provided for a symmetrical six-phase IM, showing that the proposal improves the closed-loop performance of the multi-phase drive with a low computational cost

On-line estimation of rotor variables in predictive current controllers: a case study using five-phase induction machines

Predictive current control has been recently proposed like an alternative to conventional PI-PWM current control techniques. Implemented solutions are based on inaccurate estimation of the rotor electrical variables to reduce the computational cost of the method. In this work, the utility and computational cost of predictive current control with different methods for the on-line estimation of the rotor variables are studied. Experimental results are provided to characterize the obtained benefits and drawbacks, using a five-phase induction machine as a case example

Performance Analysis of Direct Torque Controllers in Five-Phase Electrical Drives

The industrial application of electric machines has grown in the last decades, thanks to the development of microprocessors and power converters, which have permitted their use as variable-speed drives. Although three-phase machines are the common trend, the interest of the research community has recently focused on machines with more than three phases, known as multiphase machines. The principal reason lies in the exploitation of their advantages in terms of reliability, i.e., post-fault operating capability. Additionally, multiphase machines provide a better current distribution among phases, and lower current harmonic production in the power converter, than conventional three-phase machines. However, multiphase drive applications require the development of complex controllers to regulate the torque (or speed) and flux of the machine. In this regard, direct torque controllers have appeared as a viable alternative due to their easy formulation and high flexibility to incorporate control objectives. However, these controllers face some peculiarities and limitations in their use that require attention. This work aims to tackle direct torque control as a viable alternative for the regulation of multiphase drives. Special attention will be paid to the development of the control technique and the expected benefits and limitations in the obtained results. Case examples based on symmetrical five-phase induction machines with distributed windings in the motoring mode of operation will be used to this end

Hybridisation and transmedia narratives in contemporary popular music. The case of the virtual band Gorillaz.

The virtual band Gorillaz has become a reference in the music industry by mixing virtuality and presence in all its expressions (Jeffery, 2017). Indeed, this gang is presented as a group of four cartoons whose image has no reference to the real world or to fantasy, but is shown as a set of symbols through which the band manifests its identity (Prior, 2009). This band has since its inception shown itself to audiences through multiple identities based on intertextual references and postmodern popular culture names (Rambarran, 2016). The multiplicity of identities together with the diversity of animation formats and projection constitutes the essence of this visual and musical project. This paper aims to determine the band's transmedia narrative, as well as the multiple hybridisations of formats that are shown in the recorded formats and the performances. We focus on the analysis of their new album, Cracker Island (2023), whose narrative moves from virtual to physical spaces. Thus, through a visual and narrative analysis, we study the transmedia narrative on digital platforms, from December 2022 to February 2023. It also includes an analysis of three music videos and completes with a study of the band's launch performance for the Skinny Ape track, held in London and New York. At this event, the band had the collaboration of Google who developed an app where attendees could watch "Gorillaz play in real life as Murdoc, 2D, Noodle and Russel literally tower above them, playing in the middle of two of the world's most iconic skylines" (Mondosonoro, 2022). The findings evidence the storytelling of transmedia and a unique visual universe that connects with audiences, as well as highlight the possibilities of audiovisuals for contemporary music industries, such as video-volumetric (VV), immersive virtual environments (IVEs) and virtual intelligence or augmented reality, both for recorded and live formats.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

A criatividade nas universidades espanholas

Creativity is a widely studied skill and understood as an essential capacity for human development, especially in educational and professional performance. Since the entry into force of the European Higher Education Area, it has been considered a transversal competence in most university degrees, especially in Communication. The aim of this article is to identify the approach to creativity in all the subjects taught in the Audiovisual Communication and Advertising and Public Relations degrees in Spanish public universities. Thus, an analysis of the contents of the teaching guides of the curricula, a questionnaire to teachers of these degrees and a panel of experts from the professional sector have been carried out, who have reflected on the training and creative skills of the new graduates.The results indicate that, despite being considered a transversal and necessary quality for new professionals, creativity is not treated as such in the teaching guides. Although some of them contain terms related to this ability, in the rest of the programmes it is hardly present. This corroborates the gap between the needs of the professional sector and undergraduate university training, as young graduates show significant deficiencies in terms of creative capacity.  La creatividad es una habilidad ampliamente estudiada y entendida como una capacidad esencial para el desarrollo del ser humano, en especial en su desempeño educativo y profesional. Desde la entrada en vigor del Espacio Europeo de Enseñanza Superior ha sido considerada como una competencia transversal en la mayoría de los grados universitarios, especialmente en los de Comunicación. El objetivo de este artículo es identificar el abordaje que se hace de la creatividad en todas las asignaturas impartidas en los grados de Comunicación Audiovisual y de Publicidad y Relaciones Públicas en las universidades públicas españolas. De este modo, se ha realizado un análisis de contenidos de las guías docentes de los planes de estudio, un cuestionario a profesorado de estos grados y un panel de expertos del sector profesional, quienes han reflexionado sobre la formación y las destrezas creativas de los nuevos titulados.Los resultados indican que, a pesar de considerarse una cualidad transversal y necesaria para los nuevos profesionales, la creatividad no es tratada como tal en las guías docentes. Si bien en algunas de ellas aparecen recogidos términos relacionados con esta capacidad, en el resto de las programaciones apenas está presente. Se corrobora así la distancia existente entre las necesidades del sector profesional y la formación universitaria de grado, ya que los jóvenes egresados demuestran importantes carencias en cuanto a capacidad creativa.A criatividade é uma habilidade amplamente estudada e entendida como uma capacidade essencial para o desenvolvimento do ser humano, especialmente no seu desempenho educacional e profissional. Desde a entrada em vigor do Espaço Europeu do Ensino Superior, tem sido considerada uma competência transversal na maioria dos diplomas universitários, especialmente em Comunicação. O objectivo deste artigo é identificar a abordagem à criatividade em todas as disciplinas leccionadas nas licenciaturas de Comunicação Audiovisual e Publicidade e Relações Públicas nas universidades públicas espanholas. Assim, foi realizada uma análise dos conteúdos dos guias de ensino dos currículos, um questionário aos professores destes graus e um painel de peritos do sector profissional, que reflectiram sobre a formação e as competências criativas dos novos licenciados.Os resultados indicam que, apesar de ser considerada uma qualidade transversal e necessária para os novos profissionais, a criatividade não é tratada como tal nos guias de ensino. Embora alguns deles incluam termos relacionados com esta capacidade, no resto dos programas ela dificilmente está presente. Isto corrobora o fosso entre as necessidades do sector profissional e a formação universitária de graduação, uma vez que os jovens diplomados apresentam deficiências significativas em termos de capacidade criativa

A New Conformal Cooling System for Plastic Collimators Based on the Use of Complex Geometries and Optimization of Temperature Profiles

The paper presents a new design of conformal cooling channels, for application in collimator-type optical plastic parts. The conformal channels that are presented exceed the thermal and dynamic performance of traditional and standard conformal channels, since they implement new sections of complex topology, capable of meeting the high geometric and functional specifications of the optical part, as well as the technological requirements of the additive manufacturing of the mold cavities. In order to evaluate the improvement and efficiency of the thermal performance of the solution presented, a transient numerical analysis of the cooling phase has been carried out, comparing the traditional cooling with the new geometry that is proposed. The evolution of the temperature profile versus the thickness of the part in the collimating core with greater thickness and temperature, has been evaluated in a transient mode. The analysis of the thermal profiles, the calculation of the integral mean ejection temperature at each time of the transient analysis, and the use of the Fourier formula, show great improvement in the cycle time in comparison with the traditional cooling. The application of the new conformal design reduces the manufacturing cycle time of the collimator part by 10 s, with this value being 13% of the total manufacturing cycle of the plastic part. As a further improvement, the use of the new cooling system reduces the amount of thickness in the collimator core, which is above the ejection temperature of the plastic material. The improvement in the thermal performance of the design of the parametric cooling channels that are presented not only has a significant reduction in the cycle time, but also improves the uniformity in the temperature map of the collimating part surface, the displacement field, and the stresses that are associated with the temperature gradient on the surface of the optical part.This research work was supported by the University of Jaen through the Plan de Apoyo a la Investigación 2021-2022-ACCION1a POAI 2021-2022: TIC-159

From social media to the stage: the role of visual storytelling in creating the identity of the indie diva. The case of Florence and The Machine

Nowadays, the role played by social media in the promotion and marketing strategies of artists and bands is undeniable. There are many actor in the music industry that take advantage using these platforms to enhance their impact and influence amongst fans and consumers (Anderton et al., 2022; Haynes y Marschall, 2018). This new cultural digital capital thus becomes a significant element in the creation and success of their products, either live or recorded (Arriaga y Concha, 2020). Here, visual storytelling acquieres an important role in promoting their work as well as in building their identity. Hence, artists are increasingly concerned with their conception and promotion. This study focuses on the visual universe of Florence Wells and her band Florence and The Machine, one of today's most important indie artists, and in particular on her latest album, Dance Fever. In order to do so, a mixed methodology has been used, including documentary review and narrative and visual analysis applied to the album cover designed for social media, to the music videos of her six singles, to her digital storytelling —on Instagram, Spotify and Youtube and from March 2022 to September 2022— and to the artistic and stage design of the Dance Fever Tour. The findings suggest that her visual universe is a key feature of the transmedia strategy, creating her brand identity as a new model of woman singer: the indie diva, a global, humanist and even renaissance artist, distancing her from the traditional stereotypes of the female performer