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The implementation of solar photovoltaic energy is in full growth due to the need to combat global warming through the use of renewable energy. For these reasons, it is important to develop high-efficiency converters. In the past years wide bandgap devices made of SiC and GaN semiconductors have been introduced into the market. This thesis studies the benefits and feasibility of wide bandgap devices for solar photovoltaic converters particularly, the DC/AC converter. The project includes the study of the state of the art in topologies for solar photovoltaic installations and power converters for solar photovoltaic systems, and a comparison between conventional and WBG devices. The work also includes the simulation of a conventional and a WBG DC/AC converter in order to compare both technologies, as well as the modification of an existing DC/AC converter equipped with Si devices for SiC devices. Laboratory experimental testing was performed to study efficiency, total harmonic distortion and switching frequency for each converter. The results show that WBG devices, especially, the SiC cascode JFETs, increase the solar PV DC/AC converter efficiency in comparison with silicon devices. It has been proved that SiC devices enable the converters to operate at higher frequencies, and this allows a reduction in the size of the reactive components and increases the power density of the converters. The total harmonic distortion produced by the converter based on SiC is minimized at the nominal switching frequency and rated power. As a conclusion of the project, SiC devices have been verified as a suitable alternative for solar photovoltaic converter applications.

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., During voltage sags, three-phase three-wire power inverters can provide voltage support with several current injection strategies. In general, good results are ob- tained, except in overvoltage situations when one or more phase voltages exceed the allowed limit in grid codes. In three-wire inverters, this is a challenging problem because phase voltages are coupled. In this article, we present a strategy that performs independent reactive current injec- tion for each phase, which solves the overvoltage problem. This approach also includes a current-limiting technique that guarantees the injection of the maximum active power under safe current conditions. A stability analysis is carried out based on the small-gain theorem. The properties of the proposed control are experimentally validated with selected tests in a laboratory setup. A performance comparison with state-of-the-art control strategies is also included in the experimental validation., Postprint (published version)

Three-phase power converters can be represented in a complex way by transforming electrical variables to the complex plane. In this bachelor's thesis, the sliding mode control of systems described by complex state variables is studied in depth. In particular, three different implementations for three-phase inverters are proposed, based on sectors defined in the complex plane. The results are first illustrated in numerical simulations with a fixed sampling period for current control of a three-phase inverter. Eventually, they are beared out in real-time Hardware-In-the-Loop simulations by means of the use of a microcontroller., Los convertidores de potencia trifásicos se pueden representar de forma compleja por medio de la transformación de las variables eléctricas al plano complejo. En este trabajo se profundiza en el control por modo deslizante de sistemas descritos por variables de estado complejas. En particular, se proponen tres implementaciones distintas para inversores trifásicos, basadas en sectores definidos en el plano complejo. Los resultados se ilustran primero en simulaciones numéricas con un periodo de muestreo fijo para el control de corriente de un inversor trifásico. Finalmente, se corroboran en simulaciones Hardware-In-the-Loop en tiempo real mediante el uso de un microcontrolador., Els convertidors de potència trifàsics es poden representar de manera complexa per mitjà de la transformació de les variables elèctriques al pla complex. En aquest treball s'aprofundeix en el control en mode lliscant de sistemes descrits per variables d'estat complexes. En particular, es proposen tres implementacions diferents per a inversors trifàsics, basades en sectors definits en el pla complex. Els resultats s'il·lustren primer en simulacions numèriques amb un període de mostreig fix per al control de corrent d'un inversor trifàsic. Finalment, es corroboren en simulacions Hardware-In-the-Loop en temps real mitjançant l'ús d'un microcontrolador.

©2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., The high penetration of distributed energy sources is changing the paradigm of electrical networks control and management. Nowadays, power conversion systems associated to green energy plants are not only required to deliver power according to an MPPT algorithm, but should also participate in the regulation and operation of the power system, in the case of large scale systems, or provide advanced features to end users in the case of prosumers. This work proposes the use of an active transformer, incorporating series voltage regulation and current shunt regulation, through two converters in back-to-back configuration, which is able to provide all power quality services as well as resilience to end-users. This topology is advantageous in case of prosumers connected to weak and faulty grids. Moreover, the proposed active transformer also includes a battery so that island operation is offered as a service. Throughout the paper, the stability analyses and the implementation of an active transformer are presented, with special emphasis on the control of the series converter. The proposed topology is validated through real time simulations and an experimental prototype which includes a 300 kWh energy storage installation., This work was supported in part by LC-SC3-ES5-2018-2020-INTERRFACE Project under Grant GA 824330 and FlexiGRID Project under grant RTI2018-100921-B-C21., Peer Reviewed, Postprint (author's final draft)

© 2023 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., In emerging Multi-Terminal High Voltage Direct Current (MT-HVDC) systems interconnecting different Alternating Current (AC) asynchronous areas by means of Interconnecting Power Converters (IPC) different challenges arise. One of them is the control role assignment of IPCs present in these systems. Broadly speaking, the IPC controls can be classified into grid-forming or grid-following schemes for both AC and DC terminals of IPCs. This paper presents a methodology to optimize the control role assignment of the IPCs considering i) small-signal stability and, ii) control performance for different combinations of IPC roles and network power flows. The method considers multiple power flows, determines the steady-state deviations, and small-signal stability following selected events. While presenting this methodology different results on the small-signal and steady-state analysis of these systems are analyzed. Using high-fidelity linearized dynamical models, an optimization problem is formulated to assign control modes to IPCs to ensure stability and performance of the system for a set of given power flow scenarios., Postprint (published version)

En aquest document es fa un estudi al voltant dels convertidors CC-CA, més coneguts com a inversors, amb l’objectiu de dissenyar-ne un amb les característiques necessàries per a ser implementat en un monoplaça de la competició Formula Student de l’associació de l’ETSEIB. Les característiques de l’inversor es defineixen en aquesta primera part de l’estudi decidint aspectes com; la tipologia que haurà de complir l’inversor, els màxims de les variables elèctriques o el sistema de control que implementarà. Seguidament, es mostra el procés de disseny de “hardware” per tal d’aconseguir el propòsit establert. Durant aquest procés, distingirem sempre entre la part de control i la part de potència de l’inversor. En electrònica de potència es detallen: la selecció de components, el disseny dels esquemàtics, les simulacions prèvies al disseny i finalment el disseny de les plaques i sistemes que el conformen. El projecte acaba amb la fase de validació dels sistemes presentats anteriorment en el disseny, simulació i implementació de l’inversor per un cotxe elèctric de competició. On s’explica en detall els processos que s’han seguit i el motiu d’aquests. Per acabar, s’ha fet una valoració qualitativa dels objectius assolits en els diversos camps., En este documento se realiza un estudio alrededor de los convertidores CC-CA, más conocidos como inversores, con el objetivo de diseñar uno con las características necesarias para ser montado en un monoplaza de la competición Formula Student de la asociación de la ETSEIB. Las características del inversor se definen en esta primera parte del estudio con la toma de algunas decisiones como: la tipología que deberá cumplir el inversor, los máximos de las variables eléctricas o el sistema de control que va a implementar. Seguidamente, se muestra el proceso de diseño de “hardware” para conseguir el propósito establecido. Durante este proceso, distinguiremos siempre entre la parte de control y la parte de potencia del inversor. En electrónica de potencia se detallan: la selección de componentes, el diseño de esquemáticos, las simulaciones previas al diseño y, finalmente, el diseño de las placas y sistemas que lo componen. El proyecto acaba con la fase de validación de los sistemas presentados anteriormente en el diseño, simulación e implementación del inversor para un coche eléctrico de competición. Donde detallan los procesos seguidos y el motivo de estos. Para terminar, se ha hecho una valoración cualitativa de los objetivos conseguidos en los distintos campos., This document shows a study of DC-AC converters, better known as inverters, with the aim of designing one with the characteristics to be mounted on a Formula Student competition car, representing ETSEIB association. Inverter characteristics are defined in this first part of the study, helping us to make some decisions such as: the type that the inverter must be, the absolute ratings of electrical variables or the control system that will be implemented. It then shows the "hardware" design process followed to achieve the stated purpose. During this process, we will always distinguish between the control part and the power part of the inverter. In power electronics is shown: the selection of components, the schematics design, the pre-design simulations and, finally, the design of the PCBs and systems that compose it. The project ends with the validation phase of the systems presented above about design, simulation and inverter implementation for a racing electric car. Where it’s detailed the processes followed and the reason for them. Finally, a qualitative assessment was made of the objectives pursued in different fields.

El present treball té per objectiu dissenyar un sistema de refrigeració per motos de competició. En concret, l’element que s’ha refrigerat és l’inversor d’una moto de carreres 100% elèctrica que competirà a MotoStudent. El conjunt està format per un radiador, una bomba, l’inversor i maneguets. Inicialment s’ha calculat l’energia calorífica que cal extreure i, després, la temperatura a la que quedarà la placa de la base de l’inversor mitjan¸cant un model matemàtic i el programa Matlab per realitzar les iteracions. Aquests resultats són els valors més interessants de tot el treball ja que exiteix un límit de temperatura de funcionament a partir del qual l’inversor s’atura. A continuació s’ha assajat un radiador que compleix amb les dimensions màximes disponibles per poder entendre el seu comportament sota diverses condicions de treball. S’ha fet el mateix amb un model d’inversor imprès en 3D i la pèrdua de pressió que generen ambdós components ha sigut fonamental per poder seleccionar diverses bombes. La modificació de la velocitat de gir en una de les candidates ha permès observar quines noves corbes característiques s’obtenen i s’ha escollit una bomba tenint en compte les especificacions tècniques i la velocitat específica adimensional. Per tant, la metodologia aplicada combina part teòrica i part experimental. A més, al final del projecte s’ha inclòs un apartat explicant totes les consideracions mediambientals i socials que s’han tingut en compte. Per últim, però no menys important, totes les decisions rellevants que s’han pres al llarg del treball així com els resultats obtinguts s’han resumit a les conclusions. Aquestes també fan la funció de síntesi del projecte, ja que s’hi recullen les dificultats que han comportat alguns apartats i les possibles imprecisions.

Common-mode voltage (CMV) produces serious reliability and electromagnetic interference (EMI) issues in modern pulse-width modulated (PWM) electric drives. Such issues will become more prominent in the near future, as industry moves towards the introduction of wide-bandgap (WBG) semiconductor technologies operating at higher switching frequencies and also with greater ¿¿/¿¿. In this context, multiphase electric drive technologies can be of great interest, as their additional degrees of freedom can be exploited to reduce CMV. This work aims to study the potential of multiphase electric motor drive systems for CMV mitigation. To do so, a comprehensive review of the most recent scientific literature is conducted, mainly focusing on high impact works published recently. As a result, a clear and up-to-date picture of the most common multiphase technologies, i.e., (¿+1)-leg, multiple three-phase, open-end and star-connected multiphase systems is provided along with their CMV reduction potential. Not only the topologies themselves but also modulation techniques are analysed and presented, mainly focusing on star-connected systems. As a conclusion, it can be stated that such multiphase systems are promising candidates to substitute conventional three-phase motor drives as, apart from their well-known advantages (efficiency, power density, power splitting, and fault tolerance), their CMV reduction potential is confirmed. The technical information provided in this work will help researchers and field engineers to design and develop high-performance multiphase electric drives., This work has been supported in part by the Government of the Basque Country within the fund for research groups of the Basque University system IT978-16 and the research program ELKARTEK (project ENSOL2-KK-2020/00077). In addition, this work has been supported by the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya, Spain, as well as the Ministerio de Ciencia, Innovacion y Universidades of Spain within the projects PID2019-111420RB-I00, PID2020-115126RB-I00 and FEDER funds, Spain, Peer Reviewed, Postprint (published version)

Transformerless inverters for photovoltaic systems are widely used as it features low cost, volume, and weight. Thus, in recent years, its study has been of great interest to the research community. In this paper a transformerless cascade multilevel inverter for photovoltaic applications with leakage ground current compensation capability is presented. The proposed solution involves a second-order LC output filter with a particular connection, which is referred to as the DC-link-tied LC output filter. This solution is aimed to deal with the leakage-ground current issue, regardless of the considered PWM strategy. The mathematical model of the system involving such a particular LC output passive filter configuration is presented, out of which, both the differential-mode and the common-mode models are obtained. These models are used to explain the leakage-ground current improvement of the proposed DC-link-tied LC output filter. This hardware solution is evaluated under different modulation schemes to contrast the converter output response and the leakage-ground current performance. Finally, simulation and experimental results are performed using a 1 kW academic prototype to assess the performance of the proposed DC-link-tied LC output filter used in a transformerless inverter application., Peer Reviewed, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Objectius de Desenvolupament Sostenible::11 - Ciutats i Comunitats Sostenibles, Postprint (published version)

© 2022 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works., With the aim to increase standardization, reduce the cost, and obtain advanced performance features, the design of voltage-source power converter legs can be undertaken by combining several instances of a standard switching cell, properly connected in active neutral-point-clamped structures to reach the desired voltage and current ratings. These switching cells can be organized into switching-cell arrays. This design approach introduces several degrees of freedom into the design. Namely, the different options to interconnect the cells and the distribution of switching losses among these cells. This article aims to define an optimization problem to explore this design space. The design problem is formulated in different scenarios, involving different conversion configurations (dc-dc and dc-ac), different leg number of levels (two and three), and different types of available cells (standard and conduction-optimized in combination with switching-optimized). A weighted objective function is then defined in terms of leg simplicity, efficiency, and reliability. The value of the design variables that minimize the objective function with different sets of weighting factors are obtained under selected scenarios and operating conditions, to illustrate the flexibility of the converter design approach under study. The solution of the optimization problem is obtained using a surrogate optimization algorithm in MATLAB, well suited to quickly solve optimization problems involving a combination of integer design variables (the number of parallel switching cells in each converter leg position) and continuous design variables (the proportion of switching losses taken by each cell), together with linear and nonlinear constraints., Postprint (author's final draft)

The paper addresses the modelling of AC/DC systems interconnected by power converters. A non-linear model including three AC subsystems and two multiterminal DC systems interconnected by power converters are modelled in detail. The converters are set to have two different roles in the system: grid-forming and grid-following. A complete mathematical linear model including all the system dynamics is also developed following a block-based strategy which allows the overall model to be built and modified in a straightforward way. Taking advantage of this linear model, a small-signal analysis has been performed for different converter energy controller parameters. Thus, the power system dynamics and interactions have been studied for different energy controller parameters., Postprint (published version)

In alternating current microgrids, the presence of inverters is common, whose local control is based on the principles of frequency decay in the face of increases in active or reactive power, P-Q supplied to the loads shared by the voltage bus. There are a variety of approaches to calculating P-Q for both three-phase and single-phase systems. These approaches, called Electric Power Theories, have also been adapted to new technological realities, especially to the proliferation of charges where their I-V ratio is not linear, identified as NLTI. The most common are rectifier bridges with RC loads, with high harmonic distortion in current. The most advanced power theories consider NLTIs, proposing non-sinusoidal voltage and current models. These models insufficiently describe reality in the presence of sub synchronous frequency perturbations (SSFP). This work first synthesizes the main power theories and then analyzes a specific case of a singlephase inverter with the mentioned control system supplying an NLTI load, with the presence of live subharmonics. The result is a proposal of expressions for voltage and current that should serve as a basis for rethinking the analytical models of the different theories of electric power., En microxarxes de corrent altern és habitual la presència d’inversors, el control local dels quals es basa en els principis del decaïment de freqüència enfront d’increments de potència activa o reactiva, P-Q subministrades a les càrregues compartides pel bus de tensió. Hi ha una gran varietat d’enfocaments per calcular P-Q tant per sistemes trifàsics com monofàsics. Aquestes aproximacions, anomenades Teories de Potència Elèctrica, també s’han adaptat a les noves realitats tecnològiques, especialment a la proliferació de càrregues on la seva relació I-V no és lineal, identificades com a NLTI. Les més comunes són ponts rectificadors amb càrregues RC, amb elevada distorsió harmònica en corrent. Les teories de potència més avançades consideren les NLTI, proposant models de tensió i corrent no sinusoidals. Aquests models descriuen insuficientment la realitat en presència de pertorbacions a freqüències subsíncrones (SSFP). Aquest treball primer sintetitza les principals teories de potència i després s’analitza un cas concret d’un inversor monofàsic amb el sistema de control esmentat, subministrant a una càrrega NLTI, amb presència de subharmònics en tensió. El resultat és una proposta d’expressions per a tensió i corrent que han de servir de base per replantejar els models analítics de les diferents Teories de Potència Elèctrica

The industry and academia are focusing their efforts on finding more efficient and reliable electrical machines and motor drives. However, many of the motors driven by pulse-width modulated converters face the recurring problem of common-mode voltage (CMV). In fact, this voltage leads to other problems such as bearing breakdown, deterioration of the stator winding insulation and electromagnetic interferences (EMI) that can affect the lifespan and correct operation of the motors. In this sense, multilevel converters have proven to be a useful tool for solving these problems and mitigating CMV over the past few decades. Among other reasons, because they provide additional degrees of freedom when comparing with two-level converters. However, although there are several proposals in the scientific literature on this topic, no complete information has been reviewed about the CMV issues and the different multilevel alternatives that can be used to solve it. In this context, the objective of this work is to determine how multilevel power converters provide additional degrees of freedom to make the reduction of the CMV possible by using specific modulation techniques, making it easier for engineers and scientists in this field to find solutions to this problem. This document consists of a descriptive study that collects the strengths and weaknesses of most important multilevel power converters, with special emphasis on how CMV affects each of them. In addition, the differences of modulation techniques aimed to the CMV reduction are explained in terms of output voltage, operating linear range, and generated CMV. Considering this last, it is recommended to use those modulation techniques that allow the generation of CMV levels of 0 V in order to be able to completely eliminate said voltage., This work was supported in part by the Government of the Basque Country within the Fund for Research Groups of the Basque University System under Grant IT978-16; in part by the Research Program ELKARTEK under Project ENSOL2-KK-2020/00077; in part by the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya; in part by the Ministerio de Ciencia, Innovacion y Universidades of Spain under Project PID2019-111420RB-I00 and Project PID2020-115126RB-I00; and in part by the FEDER Funds., Peer Reviewed, Postprint (author's final draft)

The master thesis exposed on the present document illustrates the development of a Permanent Magnet Synchronous Motor (PMSM) model for Hardware-in-the-Loop (HiL) applications. The real-time simulations employed in HiL have proved to be an effective tool for Model-Based Designing (MBD) methodologies. The information relative to the functioning of PMSM, Variablefrequency drives and controllers for this kind of motors, as well as the required equations for the development of the model, are detailed in the first chapter of this report. Later, the software installation and the setup of hardware devices has been carried out as well. Afterwards, the most important concepts, related to real-time simulations, in computing science and numerical methods have been studied to manage the complexity of this kind of models. The modelling of the PMSM, inverter, controller, PWM generator and resolver is performed in conjunction with deep research on each field. Besides, an operating methodology, including MATLAB code scripts, has been developed for an efficiency improvement on testing execution for MBD implementations. Finally, the designing and execution of electronic connections between hardware devices have been made, and many tests performed for validating all the models created. Additionally, a comparison between tests with a real PMSM and the motor simulated with the model developed constitute the ultimate validation

©2021 Elsevier. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0, In this work, an ‘on-the-fly’ measurement technique for the monitoring of CMOS inverters performance degradation is presented. This technique allows the characterization of the circuit degradation simultaneously with the applications of the stress. In our experiments, the inversion voltage (VINV) shifts measured during the application of pulsed voltage stresses at the input. It is demonstrated that the shifts can be described by a power law that accounts for the stress time and voltage dependences. Moreover, the circuit degradation has been correlated to the NMOS and PMOS degradations. The results show that the degradation of the CMOS inverter can be evaluated from an analytical equation that considers only the shifts of two parameters (threshold voltage VTH, and mobility µ) of the two transistors in the inverter., Postprint (author's final draft)

In this thesis, a grid-connected PV system that uses a QZSI is studied, modelled and simulated using the Simulink module in the software Matlab, after conducting research on the electrical devices involved as well as on the control algorithms re-quired. The final model has been found to be stable for all irradiances studied with and without MPPT, presenting low error compared to theoretical values and an effi-ciency above 90%, concluding that the overall performance is satisfactory. However, there is room for improvement to reduce oscillations on the output current.

This paper tackles the problematic issue of measuring the efficiency at DC-DC converters operating in PFM mode, which are used for light loads such as sensor nodes. Such converters present a pulsed input current, which hinders a correct estimation of the average input power. For estimating it, two instruments were used (a power analyzer and a current waveform analyzer) as well as two methods respectively based on the following calculations: 1) exact from the voltage and current samples and 2) approximate from the average values of voltage and current., This work was supported by the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund under project TEC2016-76991-P., Postprint (updated version)

The use of DC to AC converters in renewable energy systems to transform direct to alternating current is necessary to couple these elements to the grid. In this project, a design for a DC to AC converter plant has been developed with future research purposes. In addition, direct heuristic dynamic programming, a reinforcement learning algorithm within the family of adaptive critic designs, has been analysed and simulated as a supplementary controller to improve the harmonic compensation of a shunt active filter.

Multiphase systems provides benefits compared to three-phase systems, such as improved torque per ampere, high power density, better fault tolerance, lower current per phase (due to power-splitting among a higher number of phases), and lower torque ripple, among others. Depending on the application, the system must meet determined requirements, such as the presence of harmonic content, power losses, and common-mode voltage (CMV) generation. This paper presents a comparative analysis of space vector modulation (SVM) techniques applied to a five-phase voltage source inverter with SiC switches to provide an overview of their performance. The performance of five-phase 2L SVPWM (space vector pulse width modulation), 2L+2M SVPWM, 4L SVPWM techniques, and their discontinuous versions, are analyzed by focusing on harmonic content, power losses, and CMV generation using SiC semiconductor devices. Matlab/Simulink and PLECS simulations are performed to achieve the above mentioned goal. The use of different techniques allows (1) reducing the harmonic distortion when 2L+2M SVPWM and 4L SVPWM are applied, and (2) the switching sequence of the modulation techniques can influence the switching losses. Therefore, the use of SiC switches reduces the switching losses. (3) However, CMV dv/dt increases. Therefore, it is possible to minimize the effects of the CMV dv/dt and amplitude by choosing the adequate technique., Postprint (published version)

En el presente trabajo se ha planteado el diseño e implementación de un circuito driver para cocina de inducción, que sea capaz de controlar la conmutación de un MOSFET SiC de banda ancha, que reduzca al mínimo posible los picos de corriente en la conmutación de dicho MOSFET y que trabaje en los rangos de frecuencias necesarios para calentar recipientes tanto de materiales ferromagnéticos como de aluminio. Para alcanzar los objetivos planteados se ha empezado por la elección de los componentes necesarios. Luego se ha simulado el comportamiento deseado del circuito driver. Seguido a ello se ha diseñado la PCB de tal forma que se reduzcan al mínimo las inductancias y capacitancias parásitas que podrían afectar al funcionamiento. Posterior al diseño se ha construido el circuito agregando los componentes por etapas y comprobando en cada etapa que se obtenga el comportamiento esperado. Una vez incorporados todos los componentes al circuito, se realizaron las pruebas experimentales para diferentes cargas y diferentes puntos de trabajo. Primero se probó el sistema con cargas resistivas, posterior a ello se conectó la bobina de inducción y se comprobó el funcionamiento con un recipiente ferromagnético, se analizaron los consumos de corriente y diferentes parámetros en varios niveles de tensión de ingreso, además se comprobó con diferentes señales de control, sin modular y moduladas. Al realizar estas pruebas se encontraron los parámetros que mejor eficiencia entregan en el calentamiento del recipiente de material ferromagnético. Finalizadas las pruebas con el recipiente ferromagnético, se realizaron las pruebas con un recipiente de aluminio, en este caso se ajustaron los parámetros y se encontró el punto de trabajo, así como el tipo de señal de control necesaria para que el calentamiento de este recipiente entregue la mayor eficiencia posible, dentro de las limitaciones de nuestro driver y del transistor SiC

Peer Reviewed, Postprint (author's final draft)

L’objectiu d’aquest projecte és la construcció d’un inversor o convertidor de corrent continua a corrent alterna, amb aïllament d’alta freqüència per aplicacions fotovoltaiques i el seu posterior assaig en el laboratori per validar-ne el comportament. Els passos a seguir per la construcció de l’inversor són: Definir les característiques que ha de tenir. Elecció dels diferents components que integren el circuit. Simulació del comportament teòric previst. Verificació dels components elegits a partir de les dades extretes, tensió i corrent. Construcció d’un prototip per assajar cada part. Comprovació del seu funcionament. L’aïllament d’alta freqüència que ha de proporcionar el convertidor s’aconsegueix mitjançant un transformador de potència amb nucli de ferrita. En paral·lel, s’implementa el sistema de control amb la modulació per tal de garantir el correcte funcionament del sistema. En aquesta memòria es presenta en primer lloc una descripció dels sistemes fotovoltaics, seguida d’una descripció de les diferents topologies de convertidors. Posteriorment es passa a la fase de disseny on és mostren els diferents components seleccionats, seguit de les simulacions del comportament de l’inversor. Finalment és realitza la construcció del mateix i la comprovació del seu funcionament

Grid-connected power converters, which are frequently used to link renewable generation plants with the grid, are required to provide a better functionality for large scale integration of renewables. They are expected to be gridfriendly, or even grid-supportive, instead of simply grid-feeding or grid-demanding. This paper designs a synchronous power controller for grid-connected converters in detail, emulating the electromechanical characteristics of synchronous machines and improving even its actual performance, as it is based on a virtual approach. Based on this design, the grid-interfacing units are capable of showing inertia, damping, and droop characteristics as synchronous machines and presenting thus a grid-supporting behavior. The detailed control design and experimental validation on a 10 kW laboratory setup acts as the main contribution of this paper, compared with the existing studies on generator emulation controls., Peer Reviewed, Postprint (author's final draft)

Electrical energy generation systems based on renewable energy sources have been promoted in recent years. The introduction of these systems has changed the centralized energy model to become a distributed energy model. The variability, more or less predictable, in electrical energy production based on renewable energies is a particularity of some distributed power generation systems. These variations, due to the nature of the power source, are a further disadvantage when considering the variability in energy demand. The fluctuations between energy generated and energy demanded makes it necessary to increase the use of power electronic systems in order to manage energy by storing the excess of energy during times of low demand and injecting to the grid when higher demand requires it. Some electrical energy generation systems are not able to manage variable power flow, for this reason the efficiency and their influence on the grid must be considered when their operating regime is variable. This thesis is framed within the field of electrical energy conversion in power generation systems based on renewable and non-manageable energy resources. This research scope focuses on the impact in terms of efficiency of power converters when their switches are based on transistors connected in parallel operating in case of variable power flow. Therefore, this thesis explores the energetic efficiency converters considering the influence in the current distortion by measuring the Total Harmonic Distortion (THD). To evaluate these parameters a switching strategy has been developed providing advanced configuration capabilities, selecting the number of transistors within the power switch according to the operating conditions of the power converter, applying switch multiplexed techniques and adaptive control strategies. Two main strategies are developed according to the switching frequency, maintaining a constant switching frequency in the power converter or maintaining a constant swi, En los últimos años se ha promovido la implantación de sistemas de generación eléctrica a partir de energías renovables. La introducción de estos sistemas ha cambiado el modelo de generación centralizado, dando paso a un modelo de generación distribuido. Un aspecto particular de algunos sistemas de energía distribuidos basados en energías renovables es la variabilidad, más o menos previsible, de la producción de energía eléctrica. Estas variaciones se deben a la propia naturaleza de la fuente de energía, situación que se ve aún más perjudicada si se considera la variabilidad en la demanda de energía. Las fluctuaciones entre la energía generada y la energía demandada hacen necesario el incremento de sistemas de electrónica de potencia para gestionar la energía, almacenando en momentos de baja demanda e inyectando a red cuando la demanda así lo requiere. Algunos sistemas de generación eléctrica no pueden gestionar la variabilidad en el tráfico energético, por este motivo, resulta conveniente considerar la eficiencia de los sistemas de procesamiento de energía y el impacto que pueden ejercer sobre la red eléctrica los sistemas de alimentación cuyo régimen de funcionamiento es variable. El objetivo principal de esta tesis consiste en el estudio del comportamiento e influencia que tiene en un convertidor cuando sus interruptores están constituidos por conjuntos de transistores conectados en paralelo. Para ello, se estudia el efecto que tiene en el rendimiento de un convertidor la aplicación de distintas estrategias de conmutación y el efecto en la distorsión de la corriente de salida basada en la medida del índice THD. Para evaluar estas dos características, se ha desarrollado una estrategia de conmutación basada en la gestión de los interruptores del convertidor, dotándolo de la capacidad de configurar el conjunto de transistores que conforman los interruptores en función de las condiciones de funcionamiento y aplicando técnicas de control multiplexadas, gestionando el, Postprint (published version)

High level penetration of renewable energy sources has reshaped modern electrical grids. For the future grid, distributed renewable power generation plants can be integrated in a larger scale. Control of grid-connected converters is required to achieve fast power reference tracking and further to present grid-supporting and fault ride-through performance. Among all of the aspects for converter control, the inner current loop for grid-connected converters characterizes the system performance considerably. This paper proposes a unified current loop tuning approach for grid-connected converters that is generally applicable in different cases. A direct discrete-time domain tuning procedure is used, and particularly, the selection of the phase margin and crossover frequency is analyzed, which acts as the main difference compared with the existing studies. As a general method, the approximation in the modeling of the controller and grid filter is avoided. The effectiveness of the tuning approach is validated in both simulation and experimental results with respect to power reference tracking, frequency and voltage supporting., Peer Reviewed, Postprint (published version)

El present projecte consisteix en la millora de rendiment i funcions d’un projecte antecedent. El projecte anterior presenta un convertidor CC/CA controlat per control predictiu que quan es sotmet a simulació funciona de forma molt eficient i efectiva però al fer-ho experimentalment apareixen diferències notables entre el senyal de referència i el real. Per a solucionar aquests errors es prenen les mesures possibles per a reduir el temps de resposta. Com a millora funcional s’aplica el circuit a la xarxa elèctrica com a generador elèctric fent servir el control predictiu i un PLL per a la sincronització.

At the present time, a DE0 board from Terasic/Altera, which includes a Field Programmable Gate Array (FPGA) Cyclone III, is used to control a three-phase four-level active-clamped inverter which drives a permanent-magnet motor. The project consists in designing a new FPGA-based control system that substitutes the current control system based on the DE0 board. The novel control system will consist of a single board containing a new FPGA more suitable for the specific application, the analog-to-digital converters, and all the necessary auxiliary circuitry. The FPGA content wi, [ANGLÈS] The present work summarizes the work and knowledge acquired by the author during its Master’s Thesis in the Research Group in Power Electronics, GREP. The development is based on the Multilevel Active-Clamped (MAC) power converter prototype, which was initially developed by GREP. Serving as a great introduction to the multilevel converter state-of-the-art, the prototype was tested and it was proved the need for a custom FPGA-based control platform board to drive a PMSM. The design of the board is then performed following the requirements established by the research group and the results obtained from the initial tests. Issues as power decoupling, signal conditioning and grounding strategies are discussed in the following chapters., [CASTELLÀ] La memoria aquí presentada recoge el trabajo y el conocimiento adquirido por el autor durante la elaboración de su tesis de Máster dentro del Grupo de Investigación en Electrónica de Potencia de la Universidad Politécnica de Cataluña, GREP. El trabajo elaborado se desarrolla en torno al prototipo, previamente desarrollado por los miembros del GREP, de un convertidor de potencia multinivel de tipo MAC (Multilevel Active-Clamped). La familiarización con los últimos avances en conversores multinivel se lleva a cabo mediante la fase de pruebas experimentales con este dispositivo, que a su vez demuestran la necesidad de diseñar una placa controladora específica basada en FPGA para mover un motor de imanes permanentes. Esta placa de control se diseña siguiendo los requisitos establecidos por el GREP y las necesidades surgidas en la fase de experimentación. En los capítulos del trabajo se tratan temas como el desacoplo de la alimentación, acondicionamiento de señales o metodologías de diseño de planos de masa., [CATALÀ] La memòria aquí presentada recull el treball i el coneixement adquirit per l'autor durant l'elaboració de la seva tesi de Màster dins del Grup de Recerca en Electrònica de Potència de la Universitat Politècnica de Catalunya, GREP. El treball es desenvolupa en torn al prototipus, prèviament desenvolupat pels membres del GREP, d'un convertidor de potència multinivell de tipus MAC (Multilevel Active-Clamped). La familiarització amb els darrers avanços en convertidors multinivell s'ha dut a terme mitjançant la fase de proves experimentals amb aquest prototipus, les quals han demostrat la necessitat de dissenyar una placa controladora específica basada en FPGA per controlar un motor d'imants permanents. Aquesta placa de control s'ha dissenyat seguint els requisits establerts pel GREP i les necessitats aparegudes en la fase d'experimentació. En els capítols del treball es tracten temes com el desacoblament de l'alimentació, condicionament de senyals o metodologies de disseny de plans de massa.