Aportaciones a la mejora de los sistemas de refrigeración de los convertidores de potencia del vehículo eléctrico.

201 p.Hoy en día, el VE es la opción mejor posicionada para sustituir masivamente a los automóviles tradicionales en el mercado a medio y largo plazo. Sin embargo, y a pesar de las previsiones tan optimistas, son aún muchos los factores que impiden alcanzar su despliegue; el stock de VE mundial actual corresponde solo al 0,2% del número total de vehículos de pasajeros en circulación.En lo que a los factores estrictamente tecnológicos se refiere, la tecnología del VE ha de mejorar su eficiencia. La densidad de potencia exigida en los módulos inversores en el VE es elevada y por ello es necesaria una refrigeración eficiente que permita disipar el máximo calor. En esta tesis, se dará solución a este problema, desarrollando para ello nuevas estrategias de gestión térmica y tecnologías de refrigeración avanzadas que permitan a la electrónica de potencia estar más cerca de cumplir los objetivos fijados.En consecuencia, inicialmente, se realizará una revisión exhaustiva del estado del arte, las tecnologías actuales y las tendencias futuras de las técnicas de refrigeración que harán posible la próxima generación de VEs y se analizarán los aspectos de diseño del encapsulado del módulo de potencia, para mejorar, así, la conductividad térmica, disminuir la resistencia térmica y aumentar la corriente máxima admisible.Posteriormente, se desarrollará una plataforma experimental para un sistema de refrigeración líquida basado en un ciclo de compresión a vapor y diseñado a partir de elementos convencionales ya existentes en el sistema de aire acondicionado (AC) de un VE (condensador, compresor, válvula de expansión), y se ampliará el conocimiento de la aplicación eficiente de la refrigeración por cambio de fase. En la actualidad, la investigación en sistemas de refrigeración por cambio de fase se centra en la caracterización experimental y predicción teórica del coeficiente de transferencia de calor, la caída de presión y el flujo de calor crítico (CHF, Critical Heat Fluxe). Sin embargo existe poca información sobre cómo aplicar la refrigeración por cambio de fase de manera eficiente en la gestión térmica práctica de un módulo de electrónica de potencia.Finalmente, se presentará un modelo de simulación FEM (Finite Element Method) simplificado para un módulo inversor de electrónica de potencia que permitirá analizar de manera rápida, el comportamiento térmico en función de las propiedades y parámetros térmicos de los distintos materiales que componen el módulo y de la tecnología de refrigeración empleada. No obstante, un modelo de simulación que describe totalmente el proceso de ebullición (el cambio de fase cuando el fluido circula a través del cold plate, la formación de burbujas, etc.) no resulta muy útil. El alto grado de especialización requerido por parte del usuario, la gran carga computacional resultante de acoplar distintas físicas en un mismo modelo de simulación y los grandes tiempos de ejecución son los principales inconvenientes. Por esta razón, en el modelo realizado en esta tesis, se simplificará la complejidad de la física asociada al fenómeno de cambio de fase insertando como condición de contorno un coeficiente de transferencia de calor uniforme obtenido experimentalmente

Photovoltaic Local Energy Communities—Design of New Energy Exchange Modalities—Case Study: Tolosa

Energy communities (ECs) can become a potential alternative to promote the fight against climate change. Technological progress and price reductions in recent years have made renewable energy-generation systems increasingly affordable and have generated economic benefits by reducing the value of electricity bills for community members, as well as reducing the growing environmental impact. In this context, the authors have taken Tolosa as a case study and conducted a technical and economic analysis of different possible structures of ECs (physical, virtual, with or without storage, participants with different types of consumption, etc.) by comparing them with each other. The generation capacity of the community and the optimal energy-management algorithms have been illustrated, from which the economic benefits for each member are extracted. A dynamic distribution factor is established as the basis of the algorithms, making the benefits fairer. The results obtained from this work, in addition to illustrating the economic benefits that each type of participant can receive, help to define the most appropriate community structure for each participant while highlighting the social and climate benefits that ECs can provide.This work is financially supported by the Basque Government under Grant IT1647-22 (ELEKTRIKER research group), and by the Ministerio de Ciencia e Innovación, the Agencia Estatal de Investigación. and the European Union under Grant TED2021-129930A-I00 funded by MCIN/AEI/10.13039/501100011033 and by the “European Union NextGenerationEU/PRTR”

A New Methodology to Manage FPGA Distributed Memory Content via Bitstream for Xilinx ZYNQ Devices

This paper proposes a methodology to access data and manage the content of distributed memories in FPGA designs through the configuration bitstream. Thanks to the methods proposed, it is possible to read and write the data content of registers without using the in/out ports of registers in a straightforward fashion. Hence, it offers the possibility of performing several operations, such as, to load, copy or compare the information stored in registers without the necessity of physical interconnections. This work includes two flows that simplify the designing process when using the proposed approach: while the first enables the protection or unprotection of writing on different partial regions through the bitstream, the second permits homogeneous instances of a design implemented in different reconfigurable regions to be obtained without losing efficiency. The approach is based and has been physically validated on the ZYNQ from Xilinx, and when using partially reconfigurable designs, it does not affect the hardware overhead nor the maximum operating frequency of the design.This work has been supported, within the fund for research groups of the Basque university system IT1440-22, by the Department of Education and, within PILAR ZE-2020/00022 and COMMUTE ZE-2021/00931 projects, by the Hazitek program, both of the Basque Government; the latter also by the Ministerio de Ciencia Innovación of Spain through the Centro para el Desarrollo Tecnológico Industrial (CDTI) within the projects IDI-20201264 and IDI-20220543, and through the Fondo Europeo de Desarrollo Regional 2014–2020 (FEDER funds)

Design of an Anti-Corona Device for HVAC Substation Connectors

One of the aspects to consider during high-voltage (HV) equipment design is the reduction in the probability of corona effect onset. Indeed, the corona effect is related to high electric field values beyond the equipment’s insulation levels and insulation strength, among other factors. This issue can be addressed during the design step, either by modifying the geometry of the electrical device or by including additional elements in the equipment structure to smooth out the voltage gradient along critical regions, such as anti-corona devices. The study of anti-corona devices for HV insulators is well documented, in contrast to substation connectors. Therefore, the present study proposed the design of a novel anti-corona device for HV substation connectors, including a method for the selection of its dimensions. This study shows that the relationship between the dimensional design variables and the critical electrical field on the connector is described by linear and rational functions. Thus, the design process times are cut down due to a reduction in the number of simulations required to run the assessment of the anti-corona device arrangement impact.The authors wish to thank the support from the Basque Government (GISEL research group IT1191-19 and ELEKTRIKER research group IT164-22), as well as from the University of the Basque Country UPV/EHU (GISEL research group GIU18/181 and ELEKTRIKER research group GIU20/034)

Optimal Management of an Energy Community with PV and Battery-Energy-Storage Systems

Most of current prosumer-energy-management approaches are focused on economic optimization by self-consumption maximization. Nevertheless, a lack of energy management strategies (EMS) that tackle different interaction possibilities among community-clustered solar plus battery prosumers has been detected. Furthermore, such active prosumer EMS may include participation in ancillary service markets such as automatic frequency restoration reserves (aFRR) through an optimized battery-energy storage-system (BESS) operation, as well as incorporating community-level energy management. In this study, an optimal EMS that includes aggregated aFRR-market participation of five solar plus battery prosumers participating in an energy community (EC), with the aim of reducing total costs of ownership for each individual prosumer is proposed. For its validation, different scenarios have been analyzed. The results show that the proposed EMS allows a levelized cost of energy (LCOE) reduction for all community members with respect to the base-case scenario. Moreover, the most profitable scenario for all prosumers is still the only PV.This work is financially supported by the Basque Government under the Grant IT1647-22 (ELEKTRIKER research group), and by the Ministerio de Ciencia e Innovación, the Agencia Estatal de Investigación and the European Union under the Grant TED2021-129930A-I00 funded by MCIN/AEI/ 10.13039/501100011033 and by the “European Union NextGenerationEU/PRTR”

Ibilgailu elektriko, hibrido eta erregai-piladunak: teknologiaren egoera

Ibilgailu elektriko, hibrido eta erregai-piladunek duten entzutea geroz eta handiagoa izaten ari da. I+G esfortzuak konfigurazio berri, moldagarri, fidagarriagoetan eta kostu txikiagokoetan zentratzen ari dira. Artikulu honetan, topologia hauetako teknologiaren egoera aurkezten da, sistema berri eta etorkizun handikoetan enfasia jarriz.

Ibilgailu elektrikoen potentzia-bihurgailuen hozte-metodoak

Ibilgailu elektrikoari loturiko potentzia-bihurgailuetan, korronte-dentsitate handitan (500 A ingurukoak) lan egiten duten IGBT transistoreak eta diodoak erabiltzen dira. Korronte altuak direla eta, handitu egiten dira gailu erdieroale horietan gertatzen diren kommutazio- eta kondukzio-galerak, eta ondorioz, potentzia-erdieroaleak berotu egiten dira. Moduluen efizientzia eta fidagarritasuna ziurtatzeko, beharrezkoa da hozte-sistema eraginkor eta egoki bat aukeratzea. Artikulu honetan, potentzia-bihurgailuen moduluen hozte-metodoak berrikusi eta eztabaidatuko dira.