Development of an active power filter based on wide-bandgap semiconductors

Pla de Doctorat Industrial, Generalitat de CatalynuaElectrical and electronic equipment needs sinusoidal currents and voltages to function properly. Equipment such as computers, household appliances, electric vehicle chargers, and LED lights can distort the grid and worsen grid quality. Distorted electrical grids can cause malfunctions, reduce service life, and decrease the performance of connected equipment. Industry commonly solves these problems using active power filters, which can minimise the harmonics of the grid, eliminate undesirable reactive power, and restore balance to unbalanced power grids. This thesis deals with the design and implementation of an active power filter based on wide-bandgap semiconductors, which have properties that are superior to classical silicon devices. An active power filter’s design must take advantage of these benefits to build converters that are smaller, more efficient, and consume fewer resources. However, wide-bandgap semiconductors also present design challenges. Because the most commonly used active power filters in the industry are based on two-level voltage source converters, the research for this doctoral thesis focuses on this converter topology. Moreover, its main objective is to contribute new modulation techniques that are specially designed to work with wide-bandgap semiconductors. The proposed modulations consider different aspects, such as the computational cost of the algorithms, converter losses, and the electromagnetic distortion generated. First, this thesis presents a hexagonal sigma-delta (H-S¿) modulation based on sigma-delta (S¿) modulation. The properties of this modulation are studied, and the technique is compared with other widely used modulations. The comparison considers efficiency, harmonic distortion, the electromagnetic compatibility of the converter, and the type of wideband semiconductor used. In addition, a fast algorithm is mathematically developed to simplify the presented modulation and reduce its computational cost. Secondly, this thesis presents a family of sigma-delta modulations specially designed to improve electromagnetic compatibility: the reduced common-mode voltage sigma-delta (RCMV-S¿) modulations. These modulations avoid using the vectors that generate the maximum common-mode voltage, which significantly reduces the generated electromagnetic distortion without affecting the performance of the converter and its harmonic distortion. Finally, the proposed modulations are applied in a wide-bandgap power converter working as an active filter. Thus, it is verified that the techniques presented in this thesis will obtain satisfactory results when implemented in commercial active power filters.Els equips elèctrics i electrònics necessiten corrents i tensions sinusoïdals per funcionar correctament. Existeixen equips com els ordinadors, els electrodomèstics, els carregadors de vehicle elèctric o les llums LED, que poden distorsionar la xarxa i empitjorar la qualitat d'aquesta. Les xarxes elèctriques distorsionades poden causar el mal funcionament dels equips que s'hi connecten, reduir la seva vida útil i també empitjorar la seva eficiència. A la industria és habitual utilitzar filtres actius per a solucionar aquests problemes. Els filtres actius permeten minimitzar els harmònics presents a la Δxarxa, eliminar la potència reactiva no desitjada i equilibrar xarxes elèctriques desequilibrades. Aquesta tesi tracta sobre el disseny i la implementació d'un filtre actiu basat en semiconductors de banda ampla. Aquests semiconductors presenten propietats superiors als clàssics dispositius de silici. El disseny d'un filtre actiu ha d'aprofitar aquests avantatges per a construir convertidors més petits, eficients i que consumeixin menys recursos. Tanmateix, els semiconductors de banda ampla també presenten problemes que el disseny ha de solucionar. Els filtres actius més utilitzats en la indústria són els basats en convertidors de font de tensió (voltatge source converters) amb dos nivells. La recerca d'aquesta tesi doctoral està focalitzada en aquesta topologia de convertidor, i el seu principal objectiu és l’aportació de noves tècniques de modulació especialment dissenyades per treballar amb semiconductors de banda ampla. Les modulacions proposades tenen en compte diferents aspectes: el cost computacional dels algoritmes, les pèrdues del convertidor i la distorsió electromagnètica generada. En primer lloc, es presenta una modulació sigma-delta hexagonal (H-__) que es basa en la modulació sigma-delta (ΣΔ). S'estudien les propietats d'aquesta modulació i la tècnica es compara amb altres modulacions àmpliament usades. La comparativa realitzada considera l’eficiència, la distorsió harmònica, la compatibilitat electromagnètica del convertidor i el tipus de semiconductor de banda ampla emprat. Addicionalment, es desenvolupa matemàticament un algoritme ràpid per simplificar la modulació presentada i reduir el seu cost computacional. En segon lloc, es presenta una família de modulacions sigma-delta especialment dissenyades per millorar la compatibilitat electromagnètica: les modulacions sigmadelta amb tensió en mode comú reduïda (RCMV-ΣΔ ). Aquestes modulacions eviten fer servir els vectors que generen la màxima tensió en mode comú. D'aquesta manera es redueix significativament la distorsió electromagnètica generada sense afectar de forma notable al rendiment del convertidor ni a la seva distorsió harmònica. Finalment, les modulacions proposades s'apliquen en un convertidor de potència, basat en semiconductors de banda ampla, que treballa com a filtre actiu. Això es verifica que les tècniques presentades en aquesta tesi poden ser implementades en filtres actius comercials obtenint resultats satisfactoris.Postprint (published version

Modelització, control i simulació de xarxes VSC-HVDC per a la integració de parcs eòlics marins.

El present treball presenta l’anàlisi, la modelització, el control i la simulació de xarxes mallades High Voltage Direct Current (HVDC) utilitzades per transmetre a la xarxa elèctrica l’energia generada a parcs eòlics marins. La xarxa HVDC utilitza convertidors Voltage Source Converters (VSC) per tal de mantenir la tensió constant i per transformar el corrent altern a continu i viceversa. A més, a la xarxa HVDC estudiada, s’ha considerat que un dels convertidors VSC és a la costa, mentre que els altres es troben connectats a parcs eòlics marins. Addicionalment, es realitza un anàlisi, una modelització i un estudi del control de diferents tipologies de current flow controllers (CFC) per gestionar els fluxos de corrent a la xarxa mallada HVDC. També es realitza la modelització i el control d’una turbina eòlica; i s’utilitza un model agregat per tal de treballar amb dos parcs eòlics sencers. Finalment, es duu a terme la simulació de la xarxa mallada HVDC amb els models agregats dels parcs eòlics i amb els diferents tipus de current flow controllers; emprant models ideals per estudiar els VSCs. Tots els models, simulacions i càlculs del present treball s’han realitzat utilitzant el programari MATLAB SIMULINK

Efficiency analysis of wide band-gap semiconductors for two-level and three-level power converters

© 2019 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.Power devices based on wide band-gap materials are emerging as alternatives to silicon-based devices. These new devices allow designing and building converters with fewer power losses, and are thus more highly efficient than traditional power converters. Among the wide band-gap materials in use, silicon carbide (SiC) and gallium nitride (GaN) devices are the most promising because of their excellent properties and commercial availability. This paper compares the losses produced in two-level and three-level power converters that use the aforementioned technologies. In addition, we assess the impact on the converter performance caused by the modulation technique. Simulation results under various operating points are reported and compared.Peer ReviewedPostprint (author's final draft

Effect of the heat dissipation system on hard-switching GaN-based power converters for energy conversion

The design of a cooling system is critical in power converters based on wide-bandgap (WBG) semiconductors. The use of gallium nitride enhancement-mode high-electron-mobility transistors (GaN e-HEMTs) is particularly challenging due to their small size and high power capability. In this paper, we model, study and compare the different heat dissipation systems proposed for high power density GaN-based power converters. Two dissipation systems are analysed in detail: bottom-side dissipation using thermal vias and top-side dissipation using different thermal interface materials. The effectiveness of both dissipation techniques is analysed using MATLAB/Simulink and PLECS. Furthermore, the impact of the dissipation system on the parasitic elements of the converter is studied using advanced design systems (ADS). The experimental results of the GaN-based converters show the effectiveness of the analysed heat dissipation systems and how top-side cooled converters have the lowest parasitic inductance among the studied power converters.This work was supported by the Industrial Doctorates Plan of the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya, the Centro para el Desarrollo Tecnológico Industrial (IDI-20200864), and the Ministerio de Ciencia, Innovación y Universidades of Spain within the project PID2019-111420RB-I00Peer ReviewedPostprint (published version

Efficiency comparison of power converters based on SiC and GaN semiconductors at high switching frequencies

© 2021 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.Hard-switching voltage source converters (VSC) based on wide-bandgap (WBG) devices surpass their silicon equivalents in every aspect. Nevertheless, at high switching frequencies, the efficiency significantly differs depending on the WBG semiconductor used. This article presents an extensive comparison between gallium nitride (GaN), and silicon carbide (SiC) devices in terms of efficiency. The impact of the switching frequency is evaluated for each semiconductor using two modulation techniques: the classical space vector pulse width modulation (SVPWM) technique, and the innovative hexagonal sigma-delta modulation (H-S¿). The performance and losses of both WBG technologies are analysed here using Matlab/Simulink and PLECS. Experimental results performed on two VSC converters, one based on SiC devices and the other made using GaN transistors, show the influence of the semiconductor technology and the modulation strategy on the efficiency at high switching frequenciesPeer ReviewedPostprint (published version

Fast-processing sigma-delta strategies for three-phase wide-bandgap power converters with common-mode voltage reduction

© 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.The electromagnetic compatibility of wide-bandgap (WBG) power converters can be greatly improved using spread-spectrum modulation techniques. This article proposes a family of reduced common-voltage sigma–delta modulations (RCMV- S¿ ) for voltage source converters (VSC) that use gallium nitride (GaN) semiconductors. Specifically, this article proposes three new techniques: two reduced-state sigma–delta modulations (RS- S¿1 &2), and an active sigma–delta strategy (A- S¿ ). The proposed modulation techniques reduce or eliminate the common-mode voltage (CMV) dv/dt transitions and suppress the noise spikes in the conducted electromagnetic interference spectrum. Furthermore, this article proposes the use of fast-processing quantizers for RCMV- S¿ techniques as well as for hexagonal sigma–delta (H- S¿ ). These quantizers use a novel calculation methodology that simplifies the implementation of the proposed modulations and considerably reduces their computational cost. The performance and the total harmonic distortion (THD) of RCMV- S¿ techniques are analyzed here using MATLAB/Simulink and PLECS. Experimental results performed on a VSC converter that uses GaN e-HEMTs show how RCMV- S¿ techniques considerably improve electromagnetic compatibility and exhibit similar efficiencies and THD to those of H- S¿ .This work was supported by the Industrial Doctorates Plan of the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya, the Centro para el Desarrollo Tecnológico Industrial (IDI-20200864), and in part by the Ministerio de Ciencia, Innovación y Universidades of Spain under Project PID2019-111420RB-I00.Peer ReviewedPostprint (published version

GACETA SANITARIA in 2018. Strengthening the presence in Latin America and promoting the publication of essential issues for the National Health System

Una vez más, presentamos el informe de la actividad realizada por el equipo editorial a lo largo del año anterior y los datos de desempeño de la revista, con el fin de rendir cuentas a nuestros/as lectores/as, a las personas socias de SESPAS y a la sociedad. El documento permite analizar los avances y las áreas de mejora de la revista, así como los logros alcanzados más relevantes. Este año queremos destacar el fortalecimiento de la presencia en Latinoamérica y la promoción de la publicación de temas esenciales para el Sistema Nacional de Salud

Study of the design and control of a three-phase multilevel active filter

El objetivo consiste en realizar el modelado, simulación y control de un filtro activo trifásico para la compensar la distorsión armónica en las señales de voltaje y de corriente en aplicaciones de energía renovableThis thesis addresses the issues of filtering the harmonics in electrical grids using active power filters. Power converters are the main element of an active power filter. The performance of the filter greatly depends on the type of the converter, on the control system and on the modulation technique used to command the converter. This thesis focuses in three-level neutral point clamped converters which work as shunt active power filters to compensate the current harmonics. Firstly, this thesis makes an introduction about what is the grid quality and why is important to not have currents and voltages with significant harmonics. Secondly, we describe several converter topologies which can work as an active power filter. This description includes the well-known two-level converter and also different topologies of multilevel converters. Thirdly, we present the control system used in the studied converter. The control system includes the grid synchronization, the voltage and current loops and how we detect the current harmonics to compensate. Finally, we present some modulation techniques used in multilevel converters and the modulation used in the proposed active power filter. All the simulations included in this these have been performed using the software MATLAB SIMULINK and PLEC

Modelització, control i simulació de xarxes VSC-HVDC per a la integració de parcs eòlics marins.

El present treball presenta l’anàlisi, la modelització, el control i la simulació de xarxes mallades High Voltage Direct Current (HVDC) utilitzades per transmetre a la xarxa elèctrica l’energia generada a parcs eòlics marins. La xarxa HVDC utilitza convertidors Voltage Source Converters (VSC) per tal de mantenir la tensió constant i per transformar el corrent altern a continu i viceversa. A més, a la xarxa HVDC estudiada, s’ha considerat que un dels convertidors VSC és a la costa, mentre que els altres es troben connectats a parcs eòlics marins. Addicionalment, es realitza un anàlisi, una modelització i un estudi del control de diferents tipologies de current flow controllers (CFC) per gestionar els fluxos de corrent a la xarxa mallada HVDC. També es realitza la modelització i el control d’una turbina eòlica; i s’utilitza un model agregat per tal de treballar amb dos parcs eòlics sencers. Finalment, es duu a terme la simulació de la xarxa mallada HVDC amb els models agregats dels parcs eòlics i amb els diferents tipus de current flow controllers; emprant models ideals per estudiar els VSCs. Tots els models, simulacions i càlculs del present treball s’han realitzat utilitzant el programari MATLAB SIMULINK

Tendències en Qualitat de la Xarxa, Mitigació Harmònica i Normativa per a Indústries Lleugeres i Pesades: Una Revisió

The power quality of electrical grids is becoming an important issue worldwide. The electrical grid has to deliver sinusoidal voltages and currents without frequency or amplitude variations. However, the connection of non-linear loads generates harmonics that degrade the grid quality. The presence of harmonics in the load currents has many negative consequences and can distort the voltage waveform at the point of common coupling (PCC). Thus, it is essential to mitigate the harmonics in order to maintain a suitable grid quality. This is a shared responsibility between energy suppliers, manufacturers of electric and electronic equipment, and users. In this context, this work presents, for each stakeholder, a comprehensive analysis of their responsibilities and the standards that they should meet. Additionally, this paper reviews the most common types of filters used to comply with the applicable standards in industrial applications. Finally, in order to prove that active power filters allow maintaining good power quality in all types of grid, commercially available active power filters were installed in three different grids contexts: an office building, a factory, and a stadium with a large number of LEDs. The experimental results obtained were used to evaluate the impact of active filters on grid quality. This review would help users to overcome their grid distortion problems.This work was supported by the Industrial Doctorates Plan of the Secretaria d’Universitats i Recerca del Departament d’Empresa i Coneixement de la Generalitat de Catalunya, and the Ministerio de Ciencia, Innovación y Universidades of Spain within the project PID2019-111420RB-I00.Peer ReviewedPostprint (published version