DTE - GSEP - Artículos de Revistas

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  • Publication
    Computer-Aided Design of Digital Compensators for DC/DC Power Converters
    (MDPI, 2018-11-22) Zumel Vaquero, Pablo; Fernández Herrero, Cristina; Granda Carrillo, Marlon Alberto; Lázaro Blanco, Antonio; Barrado Bautista, Andrés
    Digital control of high-frequency power converters has been used extensively in recent years, providing flexibility, enhancing integration, and allowing for smart control strategies. The core of standard digital control is the discrete linear compensator, which can be calculated in the frequency domain using well-known methods based on the frequency response requirements (crossover frequency, f(c), and phase margin, PM). However, for a given compensator topology, it is not possible to fulfill all combinations of crossover frequency and phase margin, due to the frequency response of the controlled plant and the limitations of the compensator. This paper studies the performance space (f(c), PM) that includes the set of achievable crossover frequencies and phase margin requirements for a combination of converter topology, compensator topology, and sensors, taking into account the effects of digital implementation, such as delays and limit cycling. Regarding limit cycling, two different conditions have been considered, which are related to the design of the digital compensator: a limited compensator integral gain, and a minimum gain margin. This approach can be easily implemented by a computer to speed up the calculations. The performance space provides significant insight into the control design, and can be used to compare compensator designs, select the simplest compensator topology to achieve a given requirement, determine the dynamic limitations of a given configuration, and analyze the effects of delays in the performance of the control loop. Moreover, a figure of merit is proposed to compare the dynamic performance of the different designs. The main goal is to provide a tool that identifies the most suitable compensator design in terms of the dynamic performance, the complexity of the implementation, and the computational resources. The proposed procedure to design the compensator has been validated in the laboratory using an actual DC/DC converter and a digital h
  • Publication
    Step-by-step small-signal modeling and control of a light hybrid electric vehicle propulsion system
    (MDPI, 2019-10-25) Raga Arroyo, María Carmen; Lázaro Blanco, Antonio; Barrado Bautista, Andrés; Martín Lozano, Alberto; Quesada Redondo, Isabel; Ministerio de Economía y Competitividad (España)
    This paper develops step-by-step a complete electric model of a light hybrid electric vehicle propulsion system. This model includes the vehicle mass, the radius and mass of the wheels, the aerodynamic profile of the vehicle, the electric motor and the motor drive, among other elements. Each element of the model is represented by a set of equations, which lead to getting an equivalent electric circuit. Based on this model, the outer and inner loop compensators of the motor drive control circuit are designed to provide stability and a fast dynamic response to the system. To achieve this, the steady-state equations and the small-signal model of the equivalent electric circuit are also obtained. Furthermore, as these elements are the main load of the power distribution system of the fully electric and light hybrid electric vehicle, the input impedance model of the set composed of the input filter, the motor drive, the motor, and the vehicle is presented. This input impedance is especially useful to get the system stability of the entire power distribution system.
  • Publication
    A general parameter identification procedure used for the comparative study of supercapacitors models
    (MDPI, 2019-05-01) Miniguano, Henry; Barrado Bautista, Andrés; Fernández Herrero, Cristina; Zumel Vaquero, Pablo; Lázaro Blanco, Antonio; Ministerio de Economía y Competitividad (España)
    Supercapacitors with characteristics such as high power density, long cycling life, fast charge, and discharge response are used in different applications like hybrid and electric vehicles, grid integration of renewable energies, or medical equipment. The parametric identification and the supercapacitor model selection are two complex processes, which have a critical impact on the system design process. This paper shows a comparison of the six commonly used supercapacitor models, as well as a general and straightforward identification parameter procedure based on Simulink or Simscape and the Optimization Toolbox of Matlab((R)). The proposed procedure allows for estimating the different parameters of every model using a different identification current profile. Once the parameters have been obtained, the performance of each supercapacitor model is evaluated through two current profiles applied to hybrid electric vehicles, the urban driving cycle (ECE-15 or UDC) and the hybrid pulse power characterization (HPPC). The experimental results show that the model accuracy depends on the identification profile, as well as the robustness of each supercapacitor model. Finally, some model and identification current profile recommendations are detailed.
  • Publication
    Field-programmable gate array-based linear-non-linear control with high-resolution digital pulse width modulator and high-speed embedded analogue-to-digital converter for multi-phase voltage regulator modules
    (Wiley, 2014-08) Sanz García, Clara Marina; Quintero Paredes, José de Jesús; Barrado Bautista, Andrés; Fernández Herrero, Cristina; Zumel Vaquero, Pablo; Lázaro Blanco, Antonio; Ministerio de Ciencia e Innovación (España)
    Power converters for applications with high switching frequency and tight output voltage regulation such as voltage regulator modules (VRM) for microprocessors power supplies require fast dynamic response to meet the specifications. An existing control technique known as linear-non-linear (LnL) control strategy allows improving the transient converter response by means of an easy rule for the saturation of the duty cycle. The use of a digital implementation can optimise the transient response of the multi-phase VRM with LnL. However, digital control leads to other problems derived from time discretisation and finite word length effects. The limited resolution and the sampling delay are critical issues for digital control implementation of multi-phase VRM with LnL control. As a result, a high-resolution digital pulse width modulator (DPWM) and high-speed analogue-to-digital (A/D) converter are required to obtain proper performance of the converter. This study is focused on the digital implementation of the well-known LnL control in a multi-phase VRM taking advantage of low-cost field-programmable gate array resources. A detailed description of the digital implementation of the main converter control blocks, which are the A/D converter, the compensator and the DPWM, is provided in the paper.
  • Publication
    Comprehensive Design Procedure for Racetrack Microinductors
    (Institute of Electrical and Electronics Engineers (IEEE), 2021-12) Lopez Lopez, Jaime; Zumel Vaquero, Pablo; O'Driscoll, Seamus; Pavlovic, Zoran; Murphy, Ruaidhri; O`Mathuna, Cian; Fernández Herrero, Cristina; Comunidad de Madrid; Ministerio de Educación, Cultura y Deporte (España); Universidad Carlos III de Madrid
    Present needs in efficiency and integration drive research toward the miniaturization of power converters. Among the latest components to achieve the desired degree of integration are cored micro-inductors that are still one of the hardest devices to optimize, due to the high number of freedom degrees in their fabrication. In this article, a comprehensive design procedure for these micro-inductors is presented. The proposed method makes it possible to design the optimal device in a single iteration. It also allows the designer to easily ascertain the limits of the inductor in terms of handled current and losses and provides valuable physical insights into the output of the process.
  • Publication
    Novel High-Frequency Electrical Characterization Technique for Magnetic Passive Devices.
    (Institute of Electrical and Electronics Engineers (IEEE), 2018-06) Fernández Herrero, Cristina; Pavlovic, Zoran; Kulkarni, Santosh; Mccloskey, Paul; O`Mathuna, Cian; Ministerio de Economía y Competitividad (España)
    Integrated magnetic components are key elements of the power supply on chip modules. Due to the application requirements, these magnetic devices work at very high frequency and have low inductances. Conventional small-signal tests do not provide all the required information about the magnetic device. Hence, it is important to develop new setups to apply large signals to accurately measure the performance of devices under realistic operating conditions, including nonlinear core effects. The proposed experimental setup is suitable to measure the device impedance under different large-signal test conditions, similar to those in the actual converter, since the excitation current can be configured through every winding: ac current up to 0.5 A at frequencies up to 120 MHz and dc bias current up to 2 A through one or both windings. Voltage and current are measured using commercial instrumentation. Due to the characteristics of the probes and the high frequency of the test, the attenuation and delay due to the probes and the experimental setup have to be taken into account when processing the voltage and current waveforms to calculate the impedances. The compensation test to calculate this attenuation and delay is described. Finally, the proposed setup is validated by measuring a two-phase coupled inductor microfabricated on silicon.
  • Publication
    Analysis and implementation of the autotransformer forward-flyback converter applied to photovoltaic systems
    (Elsevier Ltd., 2019-12) López del Moral Hernández, David; Barrado Bautista, Andrés; Sanz García, Clara Marina; Lázaro Blanco, Antonio; Fernández Herrero, Cristina; Zumel Vaquero, Pablo; Ministerio de Economía y Competitividad (España)
    The Distributed Maximum Power Point Tracking (DMPPT) architecture is employed to overcome the mismatching phenomena in grid-tied photovoltaic (PV) installations. In this kind of architecture, a DC-DC module integrated converter (MIC) manages each PV panel. Thanks to the DC-DC converters, the differences between PV panels do not influence others, maximizing the amount of harvested power. The MIC requirements to make this kind of solutions profitable are voltage step-down and step-up capability, low cost and high efficiency. This paper analyses the Autotransformer Forward-Flyback (AFF) converter. This converter is considered as a MIC candidate for fulfilling the requirements above. The study of the AFF converter includes the steady-state analysis and the small signal analysis in continuous conduction mode. The advantages of the AFF converter are the capability of voltage step-down and step-up; the simplicity since it only includes a single controlled switch; the use of an autotransformer; good dynamic performances and the soft switching characteristics in all the diodes. The paper includes a detailed AFF converter step-by-step design procedure, applied to 100 kW grid-tied PV installation, in which the effect of shadows has been considered. A 225 W AFF converter prototype validates the theoretical analyses, achieving an efficiency up to 94.5%.
  • Publication
    Analysis and implementation of the Buck-Boost Modified Series Forward converter applied to photovoltaic systems
    (Elsevier Ltd., 2018-12) López del Moral Hernández, David; Barrado Bautista, Andrés; Sanz García, Clara Marina; Lázaro Blanco, Antonio; Zumel Vaquero, Pablo; Ministerio de Economía y Competitividad (España)
    The mismatching phenomenon is one of the main issues in photovoltaic (PV) applications. It could reduce the generated power of a string when a PV panel has different performances from the other PV panels connected to the same string. Distributed Maximum Power Point Tracking (DMPPT) architectures are one of the most promising solutions to overcome the drawbacks associated with mismatching phenomena in PV applications. In this kind of architectures, a DC-DC module integrated converter (MIC) manages each PV panel, isolating it from the rest of the PV panels, for harvesting the maximum available power from the Sun. Due to the high number of DCDC converters used in a grid-tied PV installation, the most desired MIC requirements are high efficiency, low cost and the capability of voltage step-up and step-down. This paper proposes the Buck-Boost Modified Forward (BBMSF) converter as a good candidate to be applied in DMPPT architectures. A complete analysis of the BBMSF converter is carried out, including the steady-state analysis as well as the small signal analysis in continuous conduction mode. The main advantages of the BBMSF converter are its step-up and step-down voltage transfer function; a higher simplicity, since it only includes a single controlled switch; the soft switching characteristics in all the diodes and MOSFET, reaching in some cases ZVS and ZCS, and yielding high efficiencies; the use of an autotransformer, with better performances than a typical Forward transformer; and the good dynamic performance, like the Forward converter ones. The theoretical analyses are validated through the experimental results in a 225 W BBMSF prototype designed and built under the requirements of a 100 kW grid-tied PV installation, achieving an efficiency up to 93.6%.
  • Publication
    Analysis, design, and implementation of the AFZ converter applied to photovoltaic systems
    (Institute of Electrical and Electronics Engineers (IEEE), 2021-02) López del Moral Hernández, David; Barrado Bautista, Andrés; Sanz García, Clara Marina; Lázaro Blanco, Antonio; Zumel Vaquero, Pablo; Ministerio de Economía y Competitividad (España)
    Grid-tied photovoltaic (PV) installations with Distributed Maximum Power Point Tracking (DMPPT) architectures include a DC-DC Module Integrated Converter (MIC) for managing each PV panel, isolating it from the others, reducing the mismatching effect and maximizing the harvested power. In this paper, the Autotransformer Forward converter with type-Zeta resonant reset (AFZ) is proposed as a DMPPT architecture’s MIC candidate. The main characteristics of the AFZ converter are the high versatility due to its voltage step-up and step-down capability; the use of an optimized autotransformer with only two windings, reducing the complexity and power losses of this component; the good dynamic performances, like the Forward converter ones; the low number of components and the simplicity and high feasibility associated to the use of just one active switch. Besides, soft switching transitions are achieved thanks to the autotransformer type-Zeta resonant reset. The steady-state theoretical analysis, considering the effect of the autotransformer leakage inductance, is presented. The converter is also studied in the frequency domain, obtaining the small-signal transfer functions. A design procedure based on the requirements of a 100 kW grid-tied photovoltaic installation is described, yielding in a 225 W prototype with efficiencies up to 95.6 %. Experimental results validate the theoretical analysis.
  • Publication
    Non-inverting and Non-isolated Magnetically Coupled Buck-Boost Bidirectional DC-DC Converter
    (Institute of Electrical and Electronics Engineers (IEEE), 2020-04) Rodríguez Lorente, Alba; Barrado Bautista, Andrés; Calderón Benavente, Carlos Alberto; Fernández Herrero, Cristina; Lázaro Blanco, Antonio; Ministerio de Economía y Competitividad (España)
    A new non-isolated DC-DC converter with non-inverting output and buck-boost operation, named Magnetically Coupled Buck-Boost Bidirectional converter (MCB³), is presented in this paper. The MCB³ passive components arrangement connects the input and output ports getting an equivalent behavior to that of the Dual Active Bridge (DAB) converter, but in a non-isolated topology. This equivalency allows applying Triple Phase Shift (TPS) modulation to MCB³. TPS is known to minimize conduction losses and to achieve soft-switching at any load in the DAB converter. Throughout the paper, the features of the DAB converter are used as a reference to show the main features of the proposed converter. Moreover, other modulation strategies based on TPS modulation are used in MCB³ to operate within the minimum losses path.The multiple operation modes found on the MCB³ under TPS modulation are identified, classified, and used to find the operating points that minimize the switching and conduction losses over the power range. The analysis is shown for the boost mode that is the worst-case design. MCB³ and DAB topologies are designed and simulated for the same specification to validate the theoretical study. Finally, experimental measurements on 460W-prototypes for both topologies corroborate the equivalent operation and the main features of the MCB³.
  • Publication
    Small-signal modeling of phase-shifted full-bridge converter considering the delay associated to the leakage inductance
    (MDPI, 2021-11-01) Ochoa, Diego; Lázaro Blanco, Antonio; Zumel Vaquero, Pablo; Sanz García, Clara Marina; de Frutos, J.; Barrado Bautista, Andrés
    This paper demonstrates that in the Phase-Shifted Full-Bridge (PSFB) buck-derived converter, there is a random delay associated with the blanking time produced by the leakage inductance. This random delay predicts the additional phase drop that is present in the frequency response of the open-loop audio-susceptibility transfer function when the converter shows a significant blanking time. The existing models of the PSFB converter do not contemplate the delay and gain differences associated to voltage drop produced in the leakage inductor of the transformer. The small-signal model proposed in this paper is based on the combination of two types of analysis: the first analysis consists of obtaining a small-signal model using the average modeling technique and the second analysis consists of studying the natural response of the power converter. The dynamic modeling of the Phase-Shifted Full-Bridge converter, including the random delay, has been validated by simulations and experimental test.
  • Publication
    Comparison of different large signal measurement setups for high frequency inductors
    (MDPI, 2021-03-02) López López, Jaime; Fernández Herrero, Cristina; Barrado Bautista, Andrés; Zumel Vaquero, Pablo; Comunidad de Madrid; Ministerio de Ciencia e Innovación (España)
    The growing interest of miniaturized power converters has pushed the development of high frequency inductors integrated in Power Supply on Chip or Power Supply in Package. The proper characterization of inductor impedance is a challenge due to the dependence of the impedance on the current, the high quality factor (Q) and the high frequency range where these devices operate. In this paper, we present a comparison of different measuring methods to characterize high frequency and high Q inductors. The comparison is based on a systematic analysis of the measurement process, quantifying the influence of the parameters that affect the measurement result. Four common measurement setups are analyzed and compared. To validate the calculations, the resistance of a high frequency, high-Q inductor is characterized using every presented setup. The good match between calculations, simulation and measurement validates the analysis and the conclusions extracted.
  • Publication
    Black-box model, identification technique and frequency analysis for PEM fuel cell with overshooted transient response
    (IEEE, 2014-10-01) Raga Arroyo, María Carmen; Barrado Bautista, Andrés; Lázaro Blanco, Antonio; Fernández Herrero, Cristina; Valdivia Guerrero, Virgilio; Quesada Redondo, Isabel; Gauchía Babé, Lucía; Ministerio de Ciencia e Innovación (España)
    Fuel cells are one of the most promising energy sources, especially for onboard applications. However, fuel cells present several drawbacks, such as slow dynamic response, load-dependent voltage, and unidirectional power flow, which cause an inappropriate vehicle operation. So, secondary energy sources and power converters must be implemented in order to satisfy fast changes in the current load and to store the energy delivered by the load if regenerative braking is intended. Taking into account the number and nature of the power converters, loads, secondary energy sources, and the possibilities for the control strategies, the design of a power distribution architecture based on fuel cells for transport applications is a complex task. In order to address these architectures, modeling and simulation design tools at system level are essential. This paper proposes a complete fuel cell black-box model which reproduces the behavior of a commercial fuel cell with overshooted transient response. The identification technique applied to parameterize the model components, based on manufacturer's datasheets and a test based on load steps, is explained thoroughly. In addition, if only the fuel cell frequency response and manufacturer's datasheet are available, an alternative parameterization methodology based on the fuel cell frequency response is presented. The fuel cell black-box model is validated experimentally using a commercial proton exchange membrane fuel cell. Two different parameterizations are carried out with the aim of verifying the robustness of both the fuel cell model and the proposed identification methodology.
  • Publication
    General parameter identification procedure and comparative study of Li-Ion battery models
    (IEEE, 2020-01-01) Miniguano Miniguano, Henry Santiago; Barrado Bautista, Andrés; Lázaro Blanco, Antonio; Zumel Vaquero, Pablo; Fernández Herrero, Cristina; Ministerio de Economía y Competitividad (España)
    Accurate and robust battery models are required for the proper design and operation of battery-powered systems. However, the parametric identification of these models requires extensive and sophisticated methods to achieve enough accuracy. This article shows a general and straightforward procedure, based on Simulink and Simscape of Matlab, to build and parameterize Li-ion battery models. The model parameters are identified with the Optimization Toolbox of Matlab, by means of an iterative process to minimize the sum of the squared errors. In addition, this procedure is applied to a selection of five different models available in the literature for electric vehicle applications, obtaining a comparative study between them. Also, the performance of each battery model is evaluated through two current profiles from two driven profiles known as the Urban Driving Cycle (ECE-15 or UDC) and the Hybrid Pulse Power Characterization (HPPC). The experimental results obtained from a Li-ion polymer battery have been compared with the data provided by the models, confirming the effectiveness of the proposed procedure, and also, the application field of each model as a function of the required accuracy.
  • Publication
    Analysis and Sizing of Power Distribution Architectures Applied to Fuel Cell Based Vehicles
    (MDPI, 2018-09-29) Raga Arroyo, María Carmen; Barrado Bautista, Andrés; Miniguano Miniguano, Henry Santiago; Lázaro Blanco, Antonio; Quesada Redondo, Isabel; Martín Lozano, Alberto
    The fuel cell based vehicles powertrain is an extensive system that comprises a fuel cell (FC) as the primary energy source, a set of power converters both unidirectional and bidirectional and batteries or supercapacitors as secondary energy sources. Its design is a complex task that affects the mass, volume, cost, efficiency and fuel economy of the vehicle. This paper describes a graphic and straightforward sizing of the secondary energy sources needed to fulfil the vehicle load requirements, as well as the set of equations related to the mass, cost and volume of each one of the power distribution subsystems. Moreover, this paper analysis ten different power distribution architectures to conclude which is the most suitable secondary energy source, the minimum sizing, cost, volume and weight, depending on the amount of power delivered by the fuel cell. Also, a 1.6 kW fuel cell based architecture is implemented and testing. The experimental results confirm the proposed methodology.
  • Publication
    General Analysis of Switching Modes in a Dual Active Bridge with Triple Phase Shift Modulation
    (MDPI, 2018-09-12) Calderón Benavente, Carlos Alberto; Barrado Bautista, Andrés; Rodríguez-Nogales, Alba; Alou, Pedro; Lázaro Blanco, Antonio; Fernández Herrero, Cristina; Zumel Vaquero, Pablo
    This paper provides an exhaustive analysis of the Dual-Active-Bridge with Triple-Phase-Shift (DAB-TPS) modulation and other simpler ones, identifying all the possible switching modes to operate the DAB in both power flow directions, and for any input-to-output voltage range and output power. This study shows four cases and seven switching modes for each case when the energy flows in one direction. That means that the DAB operates up to fifty-six different switching modes when the energy flows in both directions. Analytical expressions for the inductor current, the output power, and the boundaries between switching modes are provided for all cases. Additionally, the combination of control variables to achieve Zero-Voltage-Switching (ZVS) or Zero-Current-Switching (ZCS) is provided for each case and switching mode, by showing which switching modes obtain ZVS or ZCS for the whole power range and all switches—independent of the input-to-output voltage ratio. Therefore, the most interesting cases, switching mode and modulation for using the DAB are identified. Additionally, experimental validation has been carried out with a 250 W prototype. This analysis is a proper tool to design the DAB in the optimum switching mode, reducing the RMS current and achieving to increase efficiency and the power density.
  • Publication
    Influence of the Main Design Factors on the Optimal Fuel Cell-Based Powertrain Sizing
    (MDPI, 2018-11-07) Raga Arroyo, María Carmen; Barrado Bautista, Andrés; Lázaro Blanco, Antonio; Martín Lozano, Alberto; Quesada Torres, Ana Isabel; Zumel Vaquero, Pablo
    The design of the optimal power distribution system (PDS or powertrain) for fuel cell-based vehicles is a complex task due to PDS comprising one or more power converters, several types of secondary energy sources, a fuel cell, several control loops, and protections, among others. The optimized powertrain design tries to minimize the mass, volume, and cost, and also to improve system efficiency, fuel economy (both hydrogen and electricity), and vehicle autonomy. This paper analyzes the influence of four different factors that deeply affect the optimal powertrain design, in particular: the minimum power delivered by the fuel cell, the storage of the recovered energy from the regenerative braking periods, the battery technology, and the maximum battery state-of-charge variation. The analysis of these factors is carried out over a set of 9 different fuel cell-based architectures applied to a light vehicle, and a 10th architecture corresponding to a pure electric vehicle. This analysis provides the knowledge of how these design factors affect the mass, volume, and cost of the optimal power distribution architectures, and how they can be considered in the design.
  • Publication
    Nonlinear Modeling of E-Type Ferrite Inductors Using Finite Element Analysis in 2D
    (MDPI, 2014-07-25) Salas Merino, Rosa Ana; Pleite Guerra, Jorge
    We present here a modeling procedure for inductors with an E-shaped ferrite core valid for calculating the inductance of an equivalent circuit from the linear operating region to the saturation region. The procedure was developed using Finite Elements in 2D. We demonstrate that using a 2D section of the real core the results obtained are similar to the real ones, which solves the problem of convergence that appeared when E type cores were simulated in 3D, while also saving computational cost. We also discuss the effect of the gap-thickness on the magnetic properties. The data obtained by simulation are compared with experimental results.
  • Publication
    Simulation of Waveforms of a Ferrite Inductor with Saturation and Power Losses
    (MDPI, 2014-03-04) Salas Merino, Rosa Ana; Pleite Guerra, Jorge
    We propose a model of an equivalent electrical circuit specifically designed for a ferrite inductor excited by a sinusoidal waveform. The purpose of this model is its use in a circuit simulator. We calculate the model parameters by means of Finite Elements in 2D which leads to significant computational advantages over the 3D model. We carry out the validation for a toroidal ferrite inductor by comparing the experimental results and computed ones. We consider the saturation and power losses in the core. In addition, we have tested the model for the case of square waveform in order to generalize the results. We find excellent agreement between the experimental data and the results obtained by numerical calculations.
  • Publication
    Simple procedure to compute the inductance of a toroidal ferrite core from the linear to the saturation regions
    (MDPI, 2013-06-17) Salas Merino, Rosa Ana; Pleite Guerra, Jorge
    We propose a specific procedure to compute the inductance of a toroidal ferrite core as a function of the excitation current. The study includes the linear, intermediate and saturation regions. The procedure combines the use of Finite Element Analysis in 2D and experimental measurements. Through the two dimensional (2D) procedure we are able to achieve convergence, a reduction of computational cost and equivalent results to those computed by three dimensional (3D) simulations. The validation is carried out by comparing 2D, 3D and experimental results.