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239 results on '"Freijedo, Francisco D."'

4. A Multiport Partial Power Converter for Smart Home Applications

Author

Kwon, Yong Dae, Freijedo, Francisco D., Wijekoon, Thiwanka, and Liserre, Marco

Abstract

Multiport architectures based on multiwinding transformers allow the connection of multiple electrical components to achieve smart home functionality. However, existing solutions use full-power semiconductor devices or are constrained by the complexity of the multiwinding transformer design. As an alternative, this work proposes a new multiport partial power converter (PPC) architecture. The proposed multiport PPC architecture enables the partial power by using the series resonant converter based dc transformer. In contrast to the prior art solutions, the proposed converter can be built using partial power semiconductor devices, and only a single transformer rated for a part of the overall power is required. The operating principle and design criteria are also described in the article. The effect of partial power utilization is analyzed in detail. Finally, the proposed topology has been validated using a 3 kW prototype.

Published
2024
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5. Accurate and Efficient Simulation Models for Power Electronics Transformers Based on Series-Connected Active Unity Power Factor Rectifier Modules

Author

Rubinos-Sicre, Alvaro, Freijedo, Francisco D., Wijekoon, Thiwanka, and Bakic, Miroljub

Abstract

This article contributes an efficient simulation technique for input-series output-parallel multilevel power electronics transformers based on active unity-power-factor rectifiers as building blocks. The technical motivation of the work comes from the fact that the computational burden for the simulation of these technologies tends to become unaffordable as the number of modules grows when using commercial software blocksets. This article presents a new method to drastically reduce the simulation complexity by simplifying the switching rules: In a three-phase circuit, each phase zero-crossing condition is implemented by a single and simple algebraic rule, so the complex calculations for determining the conduction state of each single diode are removed from the model. The computational enhancement and accuracy of the proposed technique are proved by experimental verification using a single-phase single-cell prototype together with multiple simulations of full-scale systems of different sizes.

Published
2024
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6. Deep Learning-Based Visual Recognition for Inline Defects in Production of Semiconductors

Author

Limam, Khouloud, Cheema, Shahzad, Mouhoubi, Samir, and Freijedo, Francisco D.

Abstract

Semiconductor manufacturing is a complex process that involves different kind of mechanical, chemical, and photo lithography treatments, such as deposition, etching, and impurity implantation. Quality inspection is vital during such the process, since defects and anomalies introduced during the production process can lead to a variety of failures in later stages. The task of manually or automatically detecting and classifying defects is challenging due to the large variation in design, material, layout, colors, and visual pattern. Existing automated optical inspection methods do not offer flexibility and scalability toward large numbers of defects or new designs. Therefore, visual inspection based on deep learning is considered as a long-term alternative for industry level quality assessment. In this article, automated visual defect identification in patterned wafers during the production process is proposed. By employing transfer learning, we trained and evaluated a number of convolutional neural network architectures including VGG, ResNet, and dense convolutional network (DenseNet), over a range of parameters for a binary and multiclass classification and determined optimal architecture. The experimental evaluation is carried out on real industrial data of patterned wafers comprising of nine different defect types and from 14 production steps. The results show that the network based on DenseNet201 achieves the highest performance up to 98.17% on binary classification and 96.04% on multiclass classification.

Published
2024
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11. Effects of discreditization methods on the performance of resonant controllers

Author

Yepes, Alejandro G., Freijedo, Francisco D., Doval-Gandoy, Jesus, Lopez, Oscar, Malvar, Jano, and Fernandez-Comesana, Pablo

Subjects
Z-transforms -- Usage, Resonance -- Control, Digital control systems -- Research, Digital control systems -- Design and construction, Power conditioning -- Methods, Power converters -- Design and construction, Business, Electronics, Electronics and electrical industries
Published
2010

12. Tuning of phase-locked loops for power converters under distorted utility conditions

Author

Freijedo, Francisco D., Doval-Gandoy, Jesus, Lopez, Oscar, and Acha, Enrique

Subjects
Phase-locked loops -- Management, Tuning (Electronics) -- Methods, Electric current converters -- Maintenance and repair, Company business management, Electric current converter, Business, Computers, Electronics, Electronics and electrical industries
Published
2009

14. Multilevel multiphase space vector PWM algorithm with switching state redundancy

Author

Lopez, Oscar, Alvarez, Jacobo, Doval-Gandoy, Jesus, and Freijedo, Francisco D.

Subjects
Electric current converters -- Analysis, Multilevel analysis -- Reports, Pulse modulation (Electronics) -- Analysis, Electric current converter, Business, Computers, Electronics, Electronics and electrical industries
Abstract

Multilevel multiphase technology combines the benefits of multilevel converters and multiphase machines. Nevertheless, new modulation techniques must be developed to take advantage of multilevel multiphase converters. In this paper, a new space vector pulsewidth modulation algorithm for multilevel multiphase voltage source converters with switching state redundancy is introduced. As in three-phase converters, the switching state redundancy permits to achieve different goals like extending the modulation index and reducing the number of switchings. This new algorithm can be applied to the most usual multilevel topologies; it has low computational complexity, and it is suitable for hardware implementations. Finally, the algorithm was implemented in a field-programmable gate array, and it was tested by using a five-level five-phase inverter feeding a motor. Index Terms--Field-programmable gate array (FPGA), multilevel converter, multiphase machine, space vector pulsewidth modulation (SVPWM), switching state redundancy.

Published
2009

15. A generic open-loop algorithm for three-phase grid voltage/current synchronization with particular reference to phase, frequency, and amplitude estimation

Author

Freijedo, Francisco D., Doval-Gandoy, Jesus, Lopez, Oscar, and Acha, Enrique

Subjects
Algorithms -- Usage, Electric current converters -- Design and construction, Electric current converters -- Control, Phase-locked loops -- Design and construction, Algorithm, Electric current converter, Business, Electronics, Electronics and electrical industries
Abstract

This paper presents a new open-loop architecture for three-phase grid synchronization based on moving average and predictive filters, where accurate measurements of phase, frequency, and amplitude are carried out in real time. Previous works establish that the fundamental positive sequence vector of a set of utility voltage/current vectors can be decoupled using Park's transformation and low-pass filters. However, the filtering process introduces delays that impair the system performance. More specifically, when the input signal frequency is shifted above the nominal, a nonzero average steady-state phase error appears in the measurements. To overcome such limitations, a suitable combination of predictive and moving average finite impulse response (FIR) filters is used by the authors to achieve a robust synchronization system for all input frequencies. Moving average filters are linear phase FIR filters that have a constant time delay at low frequencies, a characteristic that is exploited to good effect to design a predictive filter that compensates such time delays, enabling zero steady-state phase errors for shifted input frequencies. In summary, the main attributes of the new system are its good frequency adaptation, good filtering/transient response tradeoff, and the fact that its dynamics is independent of the input vector amplitude. Comprehensive experimental results validate the theoretical approach and the high performance of the proposed synchronization algorithm. Index Terms--Grid-connected converters, phase-locked loop (PLL), predictive control, synchronization.

Published
2009

41. Medium Voltage Impedance-Admittance Measurement System Based on the Cascaded H-Bridge Multilevel Converter.

Author

Petković, Marko, Hildebrandt, Nicolai, Freijedo, Francisco D., and Dujić, Dražen

Subjects
ELECTRIC potential, ELECTRIC power systems, RENEWABLE energy sources, ELECTRIC impedance, TOPOLOGY
Abstract

Recent trends in power system design such as an increasing share of renewable energy sources and smart grids are creating different subsystem interactions that require proper investigation, understanding, describing and estimating global system stability through impedance-admittance measurement and identification. This paper proposes and presents the cascaded H-bridge multilevel inverter topology for perturbation injection converter and impedance-admittance measurement. The methodology of impedance-admittance measurement is explained together with different measurements requirements. Performance and suitability of this topology for impedance-admittance measurement is evaluated through simulations. Preliminary design principles are given for the converter. System level feasibility of the solution is proposed as a main result of the work. [ABSTRACT FROM AUTHOR]

Published
2018
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50. Multilevel Multiphase Feedforward Space-Vector Modulation Technique

Author

León Galván, José Ignacio, López, Óscar, García Franquelo, Leopoldo, Doval Gandoy, Jesús, Vázquez Pérez, Sergio, Álvarez, J., Freijedo, Francisco D., and Universidad de Sevilla. Departamento de Ingeniería Electrónica

Subjects
Modulation, Space-Vector, Multilevel Multiphase
Abstract

Multiphase converters have been applied to an increasing number of industrial applications in recent years. On the other hand, multilevel converters have become a mature technology mainly in medium- and high-power applications. One of the problems of multilevel converters is the dc voltage unbalance of the dc bus. Depending on the loading conditions and the number of levels of the converter, oscillations appear in the dc voltages of the dc link. This paper presents a feedforward modulation technique for multilevel multiphase converters that reduces the distortion under balanced or unbalanced dc conditions. The proposed modulation method can be applied to any multilevel-converter topology with any number of levels and phases. Experimental results are shown in order to validate the proposed feedforward modulation technique. Ministerio de Ciencia e Innovación DPI2009-07004 Ministerio de Eduación y Ciencia TEC2007-61879

Published
2010

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