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Quasi-Z-Source Cascaded H-Bridge Multilevel Inverters for PV Applications with Fault

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Quasi-Z-Source Cascaded H-Bridge Multilevel Inverters for PV...

International Conference on Environment and Electrical Engineering (EEEIC)

作者： David Carrasco-González Pablo Horrillo-Quintero Pablo García-Triviño Raúl Sarrias-Mena Carlos Andrés García-Vázquez Luis M. Fernández-Ramirez Department of Electrical Engineering SURET Research Group University of Cadiz Algeciras Spain Department of Engineering in Automation Electronics and Computer Architecture and Networks SURET Research Group University of Cadiz Algeciras Spain

Nowadays, the use of quasi-Z-source cascaded H-bridge multilevel inverters (qZS-CHBMLI) in photovoltaic (PV) has gained their attention. They permit the single-stage power transformation of a PV generator adjusting the DC voltage independently in each module to operate each PV generator at maximum power. This paper develops a new control strategy that allows the system to continue operating after a fault in a module, by increasing the DC voltage in the operating modules. The control strategy is employed to a grid-connected qZS-CHBMLI, which consists of three cascaded qZSI powered by independent 4.8 kW PV cells. Under several operating circumstances, the proposed control system is evaluated. The results demonstrate how the control strategy applied to the system successfully reacts to the failure of a module.

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Fully distributed and resilient source seeking for robot swarms

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arXiv 2024年

作者： Bautista, Jesús Acuaviva, Antonio Hinojosa, José Yao, Weijia Jiménez, Juan García de Marina, Héctor University of Granada Granada Spain University of Lancaster United Kingdom The Department of Computer Architecture and Automation Universidad Complutense de Madrid Spain The School of Robotics Hunan University China ENTEG University of Groningen Netherlands

We propose a self-contained, resilient and fully distributed solution for locating the maximum of an unknown 3D scalar field using a swarm of robots that travel at constant speeds. Unlike conventional reactive methods relying on gradient information, our methodology enables the swarm to determine an ascending direction so that it approaches the source with an arbitrary precision. Our source-seeking solution consists of three algorithms. The first two algorithms run sequentially and distributively at a high frequency providing barycentric coordinates and the ascending direction respectively to the individual robots. The third algorithm is the individual control law for a robot to track the estimated ascending direction. We show that the two algorithms with higher frequency have an exponential convergence to their eventual values since they are based on the standard consensus protocol for first-order dynamical systems;their high frequency depends on how fast the robots travel through the scalar field. The robots are not constrained to any particular geometric formation, and we study both discrete and continuous distributions of robots within swarm shapes. The shape analysis reveals the resiliency of our approach as expected in robot swarms, i.e., by amassing robots we ensure the source-seeking functionality in the event of missing or misplaced individuals or even if the robot network splits in two or more disconnected subnetworks. In addition, we also enhance the robustness of the algorithm by presenting conditions for optimal swarm shapes, in the sense that the ascending directions can be closely parallel to the field’s gradient. We exploit such an analysis so that the swarm can adapt to unknown environments by morphing its shape and maneuvering while still following an ascending direction. We analyze our solution with robots as kinematic points in n-dimensional Euclidean spaces and extend the analysis to unicycle-like robots with constant speeds in 3D. Finally, we e

关键词： Control theory

Green Adaptation of Real-Time Web Services for Industrial CPS within a Cloud Environment

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arXiv 2024年

作者： Higuera-Toledano, M. Teresa Risco-Martín, José L. Arroba, Patricia Ayala, José L. Department of Computer Architecture and Automation Complutense University of Madrid C/Prof. José García Santesmases 9 Madrid28040 Spain Department of Electronic Engineering Technical University of Madrid Avda. Complutense 30 Madrid28040 Spain

Managing energy efficiency under timing constraints is an interesting and big challenge. This work proposes an accurate power model in data centers for time-constrained servers in Cloud computing. This model, as opposed to previous approaches, does not only consider the workload assigned to the processing element, but also incorporates the need of considering the static power consumption and, even more interestingly, its dependency with temperature. The proposed model has been used in a multi-objective optimization environment in which the Dynamic Voltage and Frequency Scaling (DVFS) and workload assignment have been efficiently optimized. © 2024, CC BY-SA.

关键词： Energy efficiency

xDEVS no_std: A Rust Crate for Real-Time DEVS on Embedded Systems

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xDEVS no_std: A Rust Crate for Real-Time DEVS on Embedded Sy...

Annual Modeling and Simulation Conference (ANNSIM)

作者： Román Cárdenas Pedro Malagón Patricia Arroba José L. Risco-Martín Integrated Systems Laboratory Universidad Politécnica de Madrid Spain Center for Computational Simulation Universidad Politécnica de Madrid Spain Department of Computer Architecture and Automation Universidad Complutense de Madrid Spain

ISBN: (数字)9781713899310

ISBN: (纸本)9798350350562

Modeling and Simulation (M&S) plays a crucial role in the design and analysis of complex systems, with the Discrete EVent System specification (DEVS) formalism being a widely adopted mathematical framework. This paper introduces xDEVS no_std, the first version of xDEVS written in the Rust programming language’s no_std environment. Rust’s features, including a data ownership mechanism, enable the development of high-performance, memory-safe simulations. xDEVS no_std focuses on Real-Time (RT) simulation for safety-critical embedded applications, leveraging Rust’s abstractions to simplify code sharing and cross-compilation. The paper outlines the implementation design and Application Programming Interface (API), which facilitates the creation of both atomic and coupled DEVS models. The RT simulator integrates with hardware, handling external interrupts and enabling interactions with the embedded system. A use case on a RISC-V microcontroller demonstrates xDEVS no_std’s capabilities, illustrating how it can effectively orchestrate tasks of Cyber-Physical System (CPS) on embedded platforms.

关键词： Embedded systems Microcontrollers Programming Cyber-physical systems Real-time systems Mathematical models Hardware Discrete-event systems Complex systems Application programming interfaces

Electrical design of a smart control and monitoring system for small horizontal-axis wind turbines

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Renewable Energy and Power Quality Journal

Renewable Energy and Power Quality Journal 2022年 20卷 116-120页

作者： Vilà, J. Luo, N. Pacheco, L. Pujol, T. Gonzalez, J.R. Ferrer, I. Massaguer, A. Massaguer, E. Department of Electrical Engineering Electronics and Automation Polytechnic School University of Girona Girona17003 Spain Department of Mechanical Engineering and Industrial Construction Polytechnic School University of Girona Girona17003 Spain Department of Computer Architecture and Technology Polytechnic School University of Girona Girona17003 Spain AULA ECOGranja Vilà sustainable engineering Camí Vell de Figueres a Olot S/N Veïnat de Pols Girona17772 Spain

The popularity of small wind turbines would rise in future, because of electricity prices are still growing. Next generation of small wind-turbines can have higher efficiency values. Under wind gusts and turbulences, the system should be very sensitive to wind conditions. In this work, it is presented a control system that can improve the performance of commercial small-scale wind turbines by including active pitch and load control. We show the electrical design of a smart active pitch control to increase the energy generation of micro-wind turbines ( © 2022, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ). All rights reserved.

关键词： Horizontal axis wind turbine

Improving the Representativeness of Simulation Intervals for the Cache Memory System

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arXiv 2024年

作者： Bueno, Nicolas Castro, Fernando Pinuel, Luis Gomez-Perez, Jose I. Catthoor, Francky Computer Architecture and Automation Department Complutense University of Madrid Madrid Spain Imec v.z.w. Kapeldreef 75 Leuven3001 Belgium KU Leuven ESAT Oude Markt 13 Leuven3000 Belgium

Accurate simulation techniques are indispensable to efficiently propose new memory or architectural organizations. As implementing new hardware concepts in real systems is often not feasible, cycle-accurate simulators employed together with certain benchmarks are commonly used. However, detailed simulators may take too much time to execute these programs until completion. Therefore, several techniques aimed at reducing this time are usually employed. These schemes select fragments of the source code considered as representative of the entire application’s behaviour –mainly in terms of performance, but not plenty considering the behaviour of cache memory levels– and only these intervals are simulated. Our hypothesis is that the different simulation windows currently employed when evaluating microarchitectural proposals, especially those involving the last level cache (LLC), do not reproduce the overall cache behaviour during the entire execution, potentially leading to wrong conclusions on the real performance of the proposals assessed. In this work, we first demonstrate this hypothesis by evaluating different cache replacement policies using various typical simulation approaches. Consequently, we also propose a simulation strategy, based on the applications’ LLC activity, which mimics the overall behaviour of the cache much closer than conventional simulation intervals. Our proposal allows a fairer comparison between cache-related approaches as it reports, on average, a number of changes in the relative order among the policies assessed –with respect to the full simulation– more than 30% lower than that of conventional strategies, maintaining the simulation time largely unchanged and without losing accuracy on performance terms, especially for memory-intensive applications. Copyright © 2024, The Authors. All rights reserved.

关键词： Cache memory

Control of Microgrid Cluster Using Raspberry Pi

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Control of Microgrid Cluster Using Raspberry Pi

Energy Technologies for Future Grids (ETFG), IEEE International Conference on

作者： David Carrasco-González Raúl Sarrias-Mena Pablo Horrillo-Quintero Francisco Llorens-Iborra Luis M. Fernández-Ramírez Department of Electrical Engineering SURET Research Group University of Cadiz (UCA) Spain Dept. of Engineering in Automation Electronics and Computer Architecture and Networks SURET Reseach Group UCA Spain

Currently, microgrid clusters (MGC) are being increasingly used owing to their benefits and human needs. MGs can be composed of power generation, consumption, and storage elements. They permit the combination of DC and AC technologies, even for a single microgrid (MG). In this paper, a new control system of a MGC consisting of two MGs connected to the main grid is developed. One of them is a DC MG that is composed of a wind turbine (WT), electrolyzer (EZ), ultracapacitor (UC), fuel cell (FC) and DC loads. The other MG is an AC MG, which is made up of a PV generator, a battery bank and AC loads. The MGC is tested under different working conditions in an experimental setup composed of a Raspberry Pi microcontroller, an OPAL-RT 4510 unit and a PC host. The experimental setup allows the system to run in real time and validate the results obtained. Finally, the control system implemented in the MGC exhibits a correct behaviour under different conditions, according to the results obtained.

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A parallel evolutionary algorithm to optimize dynamic memory managers in embedded systems

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arXiv 2024年

作者： Risco-Martín, José L. Atienza, David Colmenar, J. Manuel Garnica, Oscar Department of Computer Architecture and Automation Universidad Complutense de Madrid Madrid28040 Spain Lausanne1015 Switzerland C. E. S. Felipe II Universidad Complutense de Madrid Aranjuez28300 Spain

For the last thirty years, several Dynamic Memory Managers (DMMs) have been proposed. Such DMMs include first fit, best fit, segregated fit and buddy systems. Since the performance, memory usage and energy consumption of each DMM differs, software engineers often face difficult choices in selecting the most suitable approach for their applications. This issue has special impact in the field of portable consumer embedded systems, that must execute a limited amount of multimedia applications (e.g., 3D games, video players and signal processing software, etc.), demanding high performance and extensive memory usage at a low energy consumption. Recently, we have developed a novel methodology based on genetic programming to automatically design custom DMMs, optimizing performance, memory usage and energy consumption. However, although this process is automatic and faster than state-of-the-art optimizations, it demands intensive computation, resulting in a time consuming process. Thus, parallel processing can be very useful to enable to explore more solutions spending the same time, as well as to implement new algorithms. In this paper we present a novel parallel evolutionary algorithm for DMMs optimization in embedded systems, based on the Discrete Event Specification (DEVS) formalism over a Service Oriented architecture (SOA) framework. Parallelism significantly improves the performance of the sequential exploration algorithm. On the one hand, when the number of generations are the same in both approaches, our parallel optimization framework is able to reach a speed-up of 86.40× when compared with other state-of-the-art approaches. On the other, it improves the global quality (i.e., level of performance, low memory usage and low energy consumption) of the final DMM obtained in a 36.36% with respect to two well-known general-purpose DMMs and two state-of-the-art optimization methodologies. © 2024, CC BY-SA.

关键词： Energy utilization

Development of an interface for digital neuromorphic hardware based on an FPGA

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arXiv 2023年

作者： Harmann, René Sohlbach, Lukas Perez-Peña, Fernando Schmidt, Karsten Department of Computer Science and Engineering Frankfurt University of Applied Sciences Nibelungenplatz 1 Frankfurt60318 Germany Department of Automation Electronics and Computer Architecture and Networks School of Engineering University of Cadiz Avda. de la Universidad 10 Puerto Real11519 Spain

Exploring and understanding the functioning of the human brain is one of the greatest challenges for current research. Neuromorphic engineering tries to address this challenge by abstracting biological mechanisms and translating them into technology. Via the abstraction process and experiments with the resulting technical system, an attempt is made to obtain information about the biological counterpart. One subsection of Neuromorphic Engineering (NE) are Spiking Neural Networks (SNN), which describe the structures of the human brain more and more closely than Artificial Neural Networks (ANN). Together with their dedicated hardware, SNNs provide a good platform for developing new algorithms for information processing. In the context of these neuromorphic hardware platforms, this paper aims to develop an interface for a digital hardware platform (SPINN-3 Development Board) to enable the use of industrial or conventional sensors and thus create new approaches for experimental research. The basis for this endeavor is a Field Programmable Gate Array (FPGA), which is placed as a gateway between the sensors and the neuromorphic hardware. Overall, the developed system provides a robust solution for a wide variety of investigations related to neuromorphic hardware and SNNs. Furthermore, the solution also offers suitable possibilities to monitor all processes within the system in order to obtain suitable measurements, which can be examined in search of meaningful results. © 2023, CC BY-NC-ND.

关键词： Neural networks