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

Fault-tolerant control for a microgrid with PV systems and energy storage systems integrated into quasi-Z-source cascaded H-bridge multilevel inverter

To ensure the reliability of microgrids (MGs), this paper presents a multi-fault tolerant control for a three-phase energy storage quasi-impedance multilevel-cascaded H-bridge inverter (ES-qZS-CHBMLI) with a photovoltaic (PV) power generation-based MG. In this paper, a battery energy storage system (BESS) is implemented to smooth out the PV generation fluctuations. In the event of a fault, most studies propose the injection of a fundamental zero sequence (FZS) to balance the system after a fault. However, the FZS based-method increases the modulation and it is limited by the converter operation range. The state-of-charge (SOC) unbalanced problem has traditionally been solved by balancing the BESSs as a single unit. This paper introduces an energy management system (EMS) based on the SOC proportional power distribution to balance the power injected into the grid. When one bridge faults, it is bypassed, and the remaining bridges in that phase change their operating conditions according to the references set by the EMS. Individual phase control allows multi-fault issues to be addressed. The simulation results of a three-phase grid-connected ES-qZS-CHBMLI PV-based MG implemented in MATLAB/Simulink validate the proposed multi-fault control and EMS. In addition, an experimental validation (based on OPAL RT4520 and dSPACE MicroLabBox units) confirm these results

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)

Control of PV power plants with quasi-Z-source cascaded H-bridge multilevel inverters under failure

At the present time, quasi-Z-source cascaded H-bridge multilevel inverters (qZS-CHBMLI) have gained attention in photovoltaic (PV) applications, due to their advantages over traditional multilevel inverters. They allow single-stage power conversion of a PV power plant by independently adjusting the DC voltage in each module; thus, each PV array operates at the maximum power. This advantage permits dispensing with a DC/DC boost converter and reduces the number of modules required. This paper develops a novel control strategy for a qZS-CHBMLI connected to a single-phase system that guarantees proper operation when a fault occurs in a quasi-impedance source inverter (qZSI). The control strategy is employed in a grid-connected qZS-CHBMLI with three modules, each one with a quasi-impedance network, a 4.8 kW PV array and a voltage source inverter (VSI), with H-bridge topology. The purpose of the control system is to deliver a suitable DC voltage at the input of the VSI and ensure the grid power requirements after a fault in a module. The proposed control system is evaluated through a 40 s simulation in MATLAB/Simulink® in two cases: A) analysis of the system behaviour when there is a variation in the operation limit equation; and B) evaluation of the control strategy under dissimilar operating conditions. In addition, an experimental setup based on an OPAL RT-4510 unit and a dSPACE MicroLabBox prototyping unit is employed to validate the results. The results confirmed the correct response of the applied strategy with the failure of a single module

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 for grid-connected hybrid power plant and battery integrated into multilevel configuration

A novel optimal energy management system (EMS) using a nonlinear constrained multivariable function to optimize the operation of battery energy storages (BESs) used in a hybrid power plant with wind turbine (WT) and photovoltaic (PV) power plants is proposed in this work. The hybrid power plant uses a configuration based on a battery-stored impedance-based cascaded multilevel inverter to integrate renewable energy sources (PV power plants and WT) and BESs into the grid. The new optimal EMS seeks for satisfying the demanded power while dispatching power between BESs to optimize their efficiency. A grid-connected configuration is implemented to assess the efficiency of the suggested supervisory control under changes in renewable energy (changes in wind speed and irradiation), and in a varying active and reactive powers’ request. The BES efficiency obtained from the suggested EMS is set side by side to the BES efficiency got from a conventional EMS and a model predictive control (MPC), both working based on the state-of-charge (SOC) of the BES and balancing power EMS. The results from MATLAB simulation and the experimental results with the real-time OPAL-RT simulator (OP4510, OPAL-RT) and dSPACE MicroLabBox show the effectiveness of the suggested approach and the improvement in long-term BES efficiency

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)