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El aumento en la inserción de generadores de energía renovables en las industrias avanza y sigue desarrollándose hasta la actualidad, pero a su vez el aumento de cargas no lineales como son los aparatos electrónicos afecta la calidad de la red eléctrica con los armónicos de corriente o de tensión, contaminando y deformando la onda sinusoidal del sistema eléctrico. En la actualidad existen diferentes tipos de filtros que se encargan de atenuar este tipo fenómenos, pero la obtención de este tipo de equipos conlleva a un costo adicional. Por otro lado, los convertidores que forman parte de la estructura de las fuentes de energía renovables pueden desempeñarse como filtros activos, suministrando los armónicos generados por las cargas no lineales y evitando que se contamine la red principal mientras aun suministra energía a las cargas locales. Este convertidor trabajara en un esquema de control llamado Grid-Following donde se va a descomponer las variables de tensión y corriente al eje de coordenadas dq0 en base a la frecuencia fundamental de 50Hz, en el cual el eje directo “d” controla la potencia activa y el eje de cuadratura “q” controla la potencia reactiva. A su vez, para poder atenuar estos armónicos de corriente que contaminan la red principal, se agregará como consigna los armónicos generados por las cargas no lineales al lazo de control de corrientes dq0 para poder inyectar en forma de una onda de tensión lo armónicos que requieren las cargas no lineales, mejorando la calidad de energía de la red principal. A lo largo de este Trabajo Final de Máster (TFM) se simulará en MATLAB SIMULINK el esquema de control de una fuente fotovoltaica que suministrará potencia activa y a su vez atenuará los armónicos generados por la carga no lineal en el eje de coordenadas dq0 en base a la frecuencia fundamental. Sometiéndolo a distintos eventos para monitorear su comportamiento frente a cambios en la red eléctrica, y observar cuanto atenúa el convertidor los armónicos de corrie

Neutral-point-clamped multilevel converters are currently a suitable solution for a wide range of applications. It is well known that the capacitor voltage balance is a major issue for this topology. In this paper, a brief summary of the basic topologies, modulations, and features of neutral-point-clamped multilevel converters is presented, prior to a detailed description and analysis of the capacitor voltage balance behavior. Then, the most relevant methods to manage the capacitor voltage balance are presented and discussed, including operation in the overmodulation region, at low frequency-modulation indexes, with different numbers of AC phases, and with different numbers of levels. Both open- and closed-loop methods are discussed. Some methods based on adding external circuitry are also presented and analyzed. Although the focus of the paper is mainly DC–AC conversion, the techniques for capacitor voltage balance in DC–DC conversion are discussed as well. Finally, the paper concludes with some application examples benefiting from the presented techniques., Peer Reviewed, Postprint (published version)

En el presente artículo se realiza el análisis de un rectificador trifásico tipo puente con un interruptor en serie con la carga conmutado con ángulo simétrico. Para dicho análisis se trabajan con una serie de índices como son la corriente eficaz, las potencias activa, reactiva, aparente y de distorsión, y el factor de potencia. El objetivo es aplicar este rectificador conmutado con ángulo simétrico para la mejora del factor de potencia en microcentrales hidroeléctricas que operan en régimen autónomo, y en las que se regulan la frecuencia variando la potencia disipadas en cargas balastros mediante convertidores de corriente alterna/corriente alterna (AC-AC). Las expresiones matemáticas de los índices previos para el convertidor AC-AC son resumidas. Sin embargo, un caso de estudio es desarrollado y se demuestra la ventaja del circuito rectificador en cuanto al factor de potencia del sistema eléctrico., Postprint (published version)

Micro-size hydro power plants (µHPPs) are commonly used at remote areas to supply islanded AC micro-grids. A typical way to control grid frequency is to manipulate active power dissipated in ballast loads by AC/AC converters. However, these asymmetrically switched thyristor controlled converters consume reactive power degrading the power factor at the generator output. In this paper the operation of a symmetric angle switched, bridged three-phase rectifier and three single-phase rectifiers connected in series with ballast load, are studied to improve the power factor of the system. As a consequence, the objective is to evaluated the use of the three and single-phase rectifiers switched with symmetrical angle to improve the power factor, by reactive power compensation, at the output terminal of the electric generator of µHPPs that use ballast load to regulate frequency., Postprint (published version)

Micro-size hydro power plants are commonly used at remote areas to supply islanded AC micro-grids. A typical way to control grid frequency is to manipulate active power dissipated in ballast loads by AC/AC converters. However, these asymmetrically switched thyristor controlled converters consume reactive power degrading the power factor at the generator output. In this paper the operation of a symmetric angle switched, bridged three-phase rectifier and three single-phase rectifiers connected in series with ballast load, are studied to improve the power factor of the system. As a consequence, the objective is to evaluated the use of the three and single-phase rectifiers switched with symmetrical angle to improve the power factor, by reactive power compensation, at the output terminal of the electric generator of µHPPs that use ballast load to regulate frequency., Postprint (published version)

This paper deals with the validation of an EMI model to predict electromagnetic interferences (EMI) produced by power converters. A direct AC to AC matrix converter (MC) has been selected as experimental setup for the paper, but the modeling method can be applied to other converter topologies. The method is based on obtaining a high frequency equivalent circuit, using a combined time and frequency domain approach based on: “EMI source identification→ propagation path impedance→ derived disturbance”. The advantages of the proposed procedure are the computational time reduction and the lack of convergence problems, which may arise when using pure time domain procedures. The paper is focused on the prediction of common mode (CM) EMI of a matrix converter. The simulation results of this case will permit the calculation of currents which leak through the ground connections. Two different EMI sources are compared: one based on PWM waveforms obtained from MATLAB® model and a second one where these data are obtained experimentally from a MC prototype. This procedure allows the comparison of EMI spectra when using simulated waveforms or real source waveforms., Postprint (published version)