Model predictive control of a microgrid with energy-stored quasi-Z-source cascaded H-bridge multilevel inverter and PV systems

This paper presents a new energy management system (EMS) based on model predictive control (MPC) for a microgrid with solar photovoltaic (PV) power plants and a quasi-Z-source cascaded H-bridge multilevel inverter that integrates an energy storage system (ES-qZS-CHBMLI). The system comprises three modules, each with a PV power plant, quasi-impedance network, battery energy storage system (BESS), and voltage source inverter (VSI). Traditional EMS methods focus on distributing the power among the BESSs to balance their state of charge (SOC), operating in charging or discharging mode. The proposed MPC-EMS carries out a multi-objective control for an ES-qZS-CHBMLI topology, which allows an optimized BESS power distribution while meeting the system operator requirements. It prioritizes the charge of the BESS with the lowest SOC and the discharge of the BESS with the highest SOC. Thus, both modes can coexist simultaneously, while ensuring decoupled power control. The MPC-EMS proposed herein is compared with a proportional sharing algorithm based on SOC (SOC-EMS) that pursues the same objectives. The simulation results show an improvement in the control of the power delivered to the grid. The Integral Time Absolute Error, ITAE, achieved with the MPC-EMS for the active and reactive power is 20 % and 4 %, respectively, lower than that obtained with the SOC-EMS. A 1,3 % higher charge for the BESS with the lowest SOC is also registered. Furthermore, an experimental setup based on an OPAL RT-4510 unit and a dSPACE MicroLabBox prototyping unit is implemented to validate the simulation result

Analysis of the recording of Fibonacci lenses using photopolymers with 3-D diffusion model

In the present work, a 3-Dimensional diffusion model is proposed to predict the main properties of Diffractive Optical Elements (DOEs), recorded in photopolymers, including refractive index modulation and the evolution of the transverse intensity distribution. The model enables the selection of appropriate material characteristics based on the intended application of the DOE. Specifically, a PVA/AA photopolymer based on acrylamide is simulated using the proposed model, considering coverplating and index matching systems to mitigate the effects of thickness variation. In order to compare its properties using the suggested model, the simulation focuses on a Fibonacci Lens and the dependece of the intensity on the polymerization rate. Accordingly, axial intensity pattern is represented to prove the bifocal-behaviour of these diffractive lenses.Funded by the “Generalitat Valenciana” (Spain) (ID- IFEDER/2021/014, cofunded by EU through FEDER Pro- gramme; PROMETEO/2021/006 and INVEST/2022/419 financed by Next Generation EU), “Ministerio de Ciencia e Innovación” (Spain) (PID2021-123124OB-I00)

Hydrogen based configurations for an overhead crane with quasi-Z-source inverter

Most of the overhead cranes used to date are powered by diesel engine or electrical grid and voltage source inverter. The economic and environmental costs of fossil fuels, and the unsteady price of electricity, encourage exploring new applications for developing electric power technologies. In this scenario, the main objective of this paper is to analyze the technical and economic feasibility of two new configurations based on hydrogen system and quasi-Z-source inverter (qZSI) for an overhead crane. The first configuration uses a fuel cell (FC) connected to a qZSI to supply the crane. The second one integrates an electrolyzer (LZ) as an energy storage system (ESS) into the impedance network of the qZSI (without additional DC/DC converter), which allows to recover energy during the regenerative braking of the crane and use it to produce hydrogen. The modelling and control are described, and short simulations of the working cycle of the crane under different initial hydrogen tank levels, and long simulations with several working cycles, are considered. The results show the technical viability of the two hydrogen-based configurations and the control systems implemented, since they can power the crane under all the situations studied. Nevertheless, the configuration with FC and LZ presents a higher energy efficiency (65% vs 44% with the FC-only configuration). Regarding the economic study, both configurations are compared with a diesel-based and with a full-electric configuration powered by the grid. Analyzing both hydrogen-based configurations, the results show that the configuration with FC and FZ becomes more profitable after 1.56 years, despite the higher initial cost. However, both configurations result more expensive than those based on diesel engine and fully powered by the grid. The two proposed configurations would be more cost-effective than the initial configuration in a plausible future with a 40% decrease in hydrogen cost14 página

Methodology for the Optimal Design of a Hybrid Charging Station of Electric and Fuel Cell Vehicles Supplied by Renewable Energies and an Energy Storage System

The global energy system is changing, mainly to achieve sustainable transport technologies and clean electrical generation based on renewable sources. Thus, as fuels, electricity and hydrogen are the most promising transport technologies in order to reduce greenhouse emissions. On the other hand, photovoltaic and wind energies, including energy storage, have become the main sources of distributed generation. This study proposes a new optimal-technical sizing method based on the Simulink Design Optimization of a stand-alone microgrid with renewable energy sources and energy storage to provide energy to a wireless power transfer system to charge electric vehicles along a motorway and to a hydrogen charging station for fuel cell-powered buses. The results show that the design system can provide energy for the charging of electric vehicles along the motorway and produce the hydrogen consumed by the fuel cell-buses plus a certain tank reserve. The flexibility of the study allows the analysis of other scenarios, design requirements, configurations or types of microgrids

Autómatas programables. Programción y aplicación industrial

Contenido del curso de posgrado “Autómatas Programables: Programación y Aplicación Industriar", que presenta una introducción a la programación de autómatas de la serie Simatic S5.223 págs

Effect of Carbamazepine, Ibuprofen, Triclosan and Sulfamethoxazole on Anaerobic Bioreactor Performance: Combining Cell Damage, Ecotoxicity and Chemical Information

Pharmaceuticals and personal care products (PPCPs) are partially degraded in wastewater treatment plants (WWTPs), thereby leading to the formation of more toxic metabolites. Bacterial populations in bioreactors operated in WWTPs are sensitive to different toxics such as heavy metals and aromatic compounds, but there is still little information on the effect that pharmaceuticals exert on their metabolism, especially under anaerobic conditions. This work evaluated the effect of selected pharmaceuticals that remain in solution and attached to biosolids on the metabolism of anaerobic biomass. Batch reactors operated in parallel under the pressure of four individual and mixed PPCPs (carbamazepine, ibuprofen, triclosan and sulfametoxazole) allowed us to obtain relevant information on anaerobic digestion performance, toxicological effects and alterations to key enzymes involved in the biodegradation process. Cell viability was quantitatively evaluated using an automatic analysis of confocal microscopy images, and showed that triclosan and mixed pollutants caused higher toxicity and cell death than the other individual compounds. Both individual pollutants and their mixture had a considerable impact on the anaerobic digestion process, favoring carbon dioxide production, lowering organic matter removal and methane production, which also produced microbial stress and irreversible cell damage.Comunidad de MadridUniversidad de Alcal

Optimal energy management system using biogeography based optimization for grid-connected MVDC microgrid with photovoltaic, hydrogen system, electric vehicles and Z-source converters

Currently, the technology associated with charging stations for electric vehicles (EV) needs to be studied and improved to further encourage its implementation. This paper presents a new energy management system (EMS) based on a Biogeography-Based Optimization (BBO) algorithm for a hybrid EV charging station with a configuration that integrates Z-source converters (ZSC) into medium voltage direct current (MVDC) grids. The EMS uses the evolutionary BBO algorithm to optimize a fitness function defining the equivalent hydrogen consumption/generation. The charging station consists of a photovoltaic (PV) system, a local grid connection, two fast charging units and two energy storage systems (ESS), a battery energy storage (BES) and a complete hydrogen system with fuel cell (FC), electrolyzer (LZ) and hydrogen tank. Through the use of the BBO algorithm, the EMS manages the energy flow among the components to keep the power balance in the system, reducing the equivalent hydrogen consumption and optimizing the equivalent hydrogen generation. The EMS and the configuration of the charging station based on ZSCs are the main contributions of the paper. The behaviour of the EMS is demonstrated with three EV connected to the charging station under different conditions of sun irradiance. In addition, the proposed EMS is compared with a simpler EMS for the optimal management of ESS in hybrid configurations. The simulation results show that the proposed EMS achieves a notable improvement in the equivalent hydrogen consumption/generation with respect to the simpler EMS. Thanks to the proposed configuration, the output voltage of the components can be upgraded to MVDC, while reducing the number of power converters compared with other configurations without ZSC.This work was partially supported by Spain's Ministerio de Ciencia, Innovaci ' on y Universidades (MCIU), Agencia Estatal de Investigaci ' on (AEI) and Fondo Europeo de Desarrollo Regional (FEDER) Uni ' on Europea (UE) (grant number RTI2018-095720-B-C32), by the Federal Center for Technological Education of Minas Gerais, Brazil (process number 23062-010087/2017-51) and by the National Council of Technological and Scientific Development (CNPq-Brazil)

Averaged Dynamic Modeling and Control of a Quasi-Z-Source Inverter for Wind Power Applications

Typically, permanent magnet synchronous generator (PMSG)-driven wind turbines (WTs) present a two-stage power converter topology based on a DC/DC boost converter and voltage source inverter. In this study, this configuration is substituted by a quasi-Z-source inverter (qZSI), which is an attractive solution for boosting and converting the voltage from DC to AC in a single stage. A 2 MW PMSG WT with qZSI was studied herein. A switched dynamic model (SDM) of the qZSI (including the modeling of all switches and firing pulses) is not recommended for steady-state stability studies, long-term simulations, or large electric power systems. For such studies, two averaged dynamic models are proposed in this work. Both models present the same control system as the SDM, except for the generation of firing pulses, which is not necessary in the averaged models. The two proposed models were evaluated and compared with the SDM in the large-scale WT under different operating conditions, such as wind speed fluctuations, variable power references, and grid disturbances (voltage sag and 3(rd) and 5(th) order harmonics injection), in order to demonstrate their adequacy to represent the system response with a high reduction in the simulation time and computational efforts.This work was supported in part by the Spain's Ministerio de Ciencia, Innovacion y Universidades (MCIU), Agencia Estatal de Investigacion (AEI), and Fondo Europeo de Desarrollo Regional (FEDER) Union Europea (UE) under Grant RTI2018-095720-B-C32, in part by the National Council of Technological and Scientific Development (CNPq), Brazil, in part by the Federal Center for Technological Education of Minas Gerais, Brazil, under Process 23062-010087/2017-51, and in part by the Regional Ministry of Economic Transformation, Industry, Knowledge and Universities of Junta de Andalucia under Grant PY20_00317

Transformer‐Based Z‐Source Inverter with MVDC Link

Z‐source inverters have attracted considerable attention in renewable energy systems like photovoltaic (PV) systems due to advantages such as buck–boost power conversion in single stage, shoot-through capability, and wide range of input voltage regulation. Transformer-Based Z-source inverters (TransZSI) based on magnetically coupled inductors and reduced number of passive components can be used to improve the boost capacity of these inverters, and to increase the voltage levels. Medium voltage DC (MVDC) is being used more and more in distribution grids and renewable energy systems. This paper presents a transZ-source inverter with MVDC link where renewable energy systems and energy storage systems can be integrated. The active and reactive powers and DC voltage are controlled by acting on the modulation index and shoot-through duty cycle of the converter. The trans-Z-source inverter is evaluated under different operating conditions to illustrate its suitable operation. © 2022, European Association for the Development of Renewable Energy, Environment and Power Quality (EA4EPQ). All rights reserved

Human dentin bond strength of chlorhexidine containing universal adhesive system used in total-etch and self-etch modes

Objetivos: Evaluar la resistencia de unión a la microtracción en dentina humana de un sistema adhesivo universal con clorhexidina en su composición, en modo de grabado y lavado en 2 pasos, y en modo de autograbado. Metodología: 20 terceros molares divididos aleatoriamente en 4 grupos según el tipo de sistema adhesivo utilizado (Single Bond Universal®, 3MESPE y Peak Universal Bond®, Ultradent Products) y modo de uso (grabado total y autograbado). Se confeccionaron cuerpos de prueba sometidos al ensayo de microtracción utilizando una máquina de ensayos universales. Resultados: No se encontraron diferencias estadísticamente significativas entre los cuatro grupos estudiados. Conclusiones: La resistencia de unión de una resina compuesta a dentina humana no fue afectada por el uso de un sistema adhesivo universal que contiene clorhexidina en su composición aplicado en los modos de grabado total y autograbado.Objectives: To evaluate the microtensile bond strength to human dentin of chlorhexidine containing universal adhesive system applied in the total-etch and selfetch modes. Methods: Twenty third molars were randomly divided into four groups according to the universal adhesive system (Single Bond Universal ®, 3M ESPE and Peak Universal Bond®, Ultradent) and application mode used (total-etch and self-etch). Specimens were prepared and subjected to a microtensile bond strength using a MTS SANS universal testing machine. Results: No statistically significant differences were found in the microtensile bond strength between the four groups studied. Conclusions: The bond strength of a composite resin to human dentin was not affected by the use of a universal adhesive system with chlorhexidine in its composition applied in the total-etch and self-etch modes