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

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

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

An open-phase fault detection method for six-phase induction motor drives

Malaga (Spain), 4th to 6th April, 2017 Comunicaciones del Congreso Publicadas en: Renewable Energy and Power Quality Journal (RE&PQJ) ISSN 2172 038X, No.15 April 2017Induction machines (IM) with multiple sets of three-phase windings are a real alternative in safety- critical applications due to their inherent redundancy and extra number of freedom degrees. These properties can be used to devel op a fault-tolerant system without extra hardware. The fault detection is mandatory in the creation of a fault tolerant system. Since, the fault localization allows to adapt the control scheme of this anomalous mode of operation. Nowadays, open-phase faults (OPFs) and six-phase IMs are hot topics in the literature of fault-tolerant drives. Thus, this paper presents an open-phase fault detection method for a six-phase IM drive . The detection method is based o n the vector space decomposition (VSD), taking the components of the secondary orthogonal subspace to localize the open-phase fault. The goodness of the proposed method is validated with simulation resultsMinisterio de Ciencia e Innovacion ENE2014-52536-C2–1-

Evolutionary Gaps Stator Current Control of Multi-phase Drives Balancing Harmonic Content

Multiphase machines are increasingly used in research and industry applications due to their inherent advantages. Stator current control is a common strategy for this type of systems. The most important issue it must face is regulation of currents in the torque producing plane and the harmonic plane. For this task, finite control set model predictive control (FCS-MPC) constitutes an interesting alternative to methods using modulation. However, the implementation of FCS-MPC is characterized by a high computational demand, limiting the sampling frequency. This work proposes a predictive algorithm that needs less computation time. As a result, the sampling period can be reduced while producing predictive control. This brings about several benefits resulting from improved current tracking. The proposed method avoids the combinatorial optimization phase of standard FCS-MPC, which is the most time-consuming part. The algorithm is based on physical insights obtained from the application of FCS-MPC to multiphase drives leading to the concept of evolutionary gaps regions. The experimental results for a five-phase motor demonstrate improved performance. Moreover, the method is flexible enough to balance the tradeoff appearing between the torque producing plane and the harmonic plane.Ministerio de Ciencia e Innovación TED2021-129558B-C22 PID2021-125189OBI0