Open Access
Intelligent control of wind-assisted PHEVs smart charging station
(MDPI, 2019) Hassan, Syed Zulqadar; Kamal, Tariq; Riaz, Muhammad Hussnain; Shah, Syed Aamir Hussain; Ali, Hina Gohar; Riaz, Muhammad Tanveer; Sarmad, Muhammad; Zahoor, Amir; Khan, Muhammad Abbas; Pascual Miqueleiz, Julio María; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación
Two technology opportunities, integration of renewable energy sources and the electrification of vehicles are being encouraged to reduce dependency on fossil fuels and pollution problems. Nevertheless, the huge increase of plug-in hybrid electric vehicles (PHEVs) on roads will cause an additional load in demand, especially at rush hours, and therefore, threatens the stability of existing power grids. Considering PHEV stay for several hours in the workplace, (i.e., university), this may provide an inimitable framework to charge PHEV from wind in the workplace. This paper introduces the possibility of introducing intelligent control of wind power and battery storage units as supplementary power sources for future PHEV charging demands during rush hours. The operation of the proposed algorithm is based on the priority levels of PHEVs charging, and fluctuations in DC link voltage levels due to the variation in wind speed. The priorities of PHEVs charging are developed according to their power requirements, maximum rating of distribution transformer and park duration of PHEVs in the workplace during wind speed. Various non-isolated proportional-integral controllers and improved intelligent fuzzy control are used to keep a minimum critical DC link voltage to permit the power conditioning system to operate a charging station uninterruptedly, even at low wind speed. The improved intelligent fuzzy controller also contributes to minimizing the stress on the DC bus and ensures quality output power. The performance of the proposed charging station is verified for the real PHEV under real-world record of wind speed. All the energy sources, electric charging station and their controllers are designed in MATLAB/Simulink. Finally, the feasibility of proposed charging station is checked experimentally in the laboratory.
Open Access
Adjustment of the fuzzy logic controller parameters of the energy management strategy of a grid-tied domestic electro-thermal microgrid using the Cuckoo search algorithm
(IEEE, 2019) Arcos Avilés, Diego; García Gutiérrez, Gabriel; Guinjoan Gispert, Francesc; Pascual Miqueleiz, Julio María; Marroyo Palomo, Luis; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
During the last century, population growth, together with economic development, has considerably increased the energy demand and, although renewable energies are becoming an alternative, still total energy supply is mainly non-renewable, causing well-known negative effects such as pollution and global warming. On the other hand, technological advances have allowed the development of increasingly efficient distributed generation systems and the emergence of microgrids, whose studies have been focused on architecture, elements, and objectives of the associated energy management strategies. In this regard, energy management strategies based on a Fuzzy Logic controller have been developed for electro-thermal microgrids where parameter optimization has been carried out through heuristic procedures of trial and error with acceptable results but involving a high computational cost. To solve the aforementioned drawbacks, in the present work the use of Cuckoo Search optimization nature-inspired algorithm that allows the adjustment of Fuzzy Logic controller parameters and ensures a higher quality of energy management is proposed. Obtained results show encouraging outcomes for the use of these meta-heuristic optimization algorithms.
Open Access
Fuzzy-based energy management of a residential electro-thermal microgrid based on power forecasting
(IEEE, 2018) Arcos Avilés, Diego; Gordillo, Rodolfo; Guinjoan Gispert, Francesc; Sanchis Gúrpide, Pablo; Pascual Miqueleiz, Julio María; Marietta, Martin P.; Marroyo Palomo, Luis; Ibarra, Alexander; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
In this paper, an energy management strategy based on microgrid power forecasting is applied to a residential grid-connected electro-thermal microgrid with the aim of smoothing the power profile exchanged with the grid. The microgrid architecture under study considers electrical and thermal renewable generation, energy storage system (ESS), and loads. The proposed strategy manages the energy stored in the ESS to cover part of the energy required by the thermal generation system for supplying domestic hot water to the residence. The simulation results using real data and the comparison with previous strategy have demonstrated the effectiveness of the proposed strategy.
Open Access
Estrategias avanzadas de gestión energética basadas en predicción para microrredes electrotérmicas
(2016) Pascual Miqueleiz, Julio María; Marroyo Palomo, Luis; Sanchis Gúrpide, Pablo; Ingeniería Eléctrica y Electrónica; Ingeniaritza Elektrikoa eta Elektronikoa
El primer objetivo concreto de la tesis consiste en estudiar los perfiles de potencia de los diferentes elementos de la microrred y su interacción, ya sea directa, en el caso de flujos de potencia confluyentes, o indirecta, en el caso de la posible interacción de distintos sistemas (sistema eléctrico y térmico). Este análisis se realiza en el Capítulo 2. El segundo objetivo es el diseño de estrategias de gestión energética para la microrred y evaluación comparativa en base a criterios específicos de calidad. Este objetivo se desarrolla en los Capítulos 3 a 7. En los Capítulos 3 y 4, se desarrollan y analizan estrategias de gestión sin datos de predicción. Las estrategias del Capítulo 3 basan su gestión en el control de la batería en función del balance de potencias instantáneo, mientras que en el Capítulo 4 se desarrollan estrategias de similar estructura, pero basándose en el balance energético diario en la microrred. Consecuencia del análisis de estas primeras estrategias, se verá la necesidad de utilizar predicción de la potencia. Para ello, se analiza en el Capítulo 5 la predicción del consumo y de la generación estudiando por separado los datos medidos por los vatímetros y la estación meteorológica de la microrred, los datos de predicción meteorológica ofrecidos por el servidor utilizado y los modelos físicos que ayudan a transformar los datos de variables ambientales en datos de potencia generada. Posteriormente, en el Capítulo 6 se analizan las ventajas de la utilización de los datos de predicción y cómo utilizarlos, poniéndose en práctica su uso. La estructura del control propuesto es similar a la vista en el Capítulo 4, pero, debido a la naturaleza de los datos de predicción, se desarrolla un nuevo control de la batería basado en el error de la predicción. Este control mejora notablemente los resultados en comparación con los obtenidos en las estrategias previas. No obstante, del análisis de esta estrategia, queda patente la influencia que tiene el sistema térmico sobre el eléctrico, que puede ser negativa si se deja que evolucione de forma independiente. Por el contrario, el sistema térmico puede ser muy beneficioso si la estrategia toma el control del mismo. Así, en el Capítulo 7, se hace uso de una caldera eléctrica gestionable, que hace de nexo entre el sistema eléctrico y el térmico, y un depósito de agua caliente que sirve de almacén de energía térmica. De esta forma, se fusiona la gestión de ambos sistemas creando un único sistema energético, denominado microrred electrotérmica. El tercer objetivo de la tesis es la validación experimental de los resultados obtenidos. Así, realizados los análisis de las distintas estrategias mediante simulación, se prueba su funcionamiento en la microrred instalada en el Laboratorio de Energías Renovables de la UPNA. Su implementación y los resultados obtenidos se detallan en el Capítulo 8. Finalmente, en el Capítulo 9 se repasan las principales conclusiones y se presentan las líneas futuras.
Open Access
On the requirements of the power converter for second-life lithium-ion batteries
(IEEE, 2019) Berrueta Irigoyen, Alberto; San Martín Biurrun, Idoia; Pascual Miqueleiz, Julio María; Sanchis Gúrpide, Pablo; Ursúa Rubio, Alfredo; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC; Ingeniería Eléctrica, Electrónica y de Comunicación; Gobierno de Navarra / Nafarroako Gobernua
The use of lithium-ion batteries is increasing year after year, especially in the automotive sector. Given the high requirements of electric vehicles, their energy storage systems are discarded when they still have around 70% of its initial capacity. These discarded batteries are being studied as a low-price option for stationary systems, mostly related to renewable energy generation, with lower battery requirements. However, the increasing dispersion of cell capacity detailed in this contribution limits the use of second-life cells if regular battery management systems and power converters. We present in this contribution an experimental comparison of the capacity dispersion between fresh and second-life cells, and detail the relationship between the capacity dispersion and the required BMS functionality. Furthermore, we include the ageing phenomena in the analysis by means of experimental ageing results, given that the capacity dispersion is enlarged as the battery ages. After this, we use this data to quantify advantages and disadvantages of a combined BMS and power converter, based on a multilevel topology, compared to a conventional BMS. The most relevant result, when a 55-cell battery is analysed, is a 65% increase in capacity during its whole second life if the BMS and power converter are combined by means of a multilevel topology. The increased level of complexity required by the combined BMS-power converter architecture is analysed in this contribution, providing a convenient tool for the selection of the most suitable option for each application.
Open Access
An energy management system design using fuzzy logic control: smoothing the grid power profile of a residential electro-thermal microgrid
(IEEE, 2021) Arcos Avilés, Diego; Pascual Miqueleiz, Julio María; Guinjoan Gispert, Francesc; Marroyo Palomo, Luis; García Gutiérrez, Gabriel; Gordillo, Rodolfo; Llanos, Jacqueline; Sanchis Gúrpide, Pablo; Motoasca, Emilia; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This work deals with the design of a Fuzzy Logic Control (FLC) based Energy Management System (EMS) for smoothing the grid power prole of a grid-connected electro-thermal microgrid. The case study aims to design an Energy Management System (EMS) to reduce the impact on the grid power when renewable energy sources are incorporated to pre-existing grid-connected household appliances. The scenario considers a residential microgrid comprising photovoltaic and wind generators, at-plate collectors, electric and thermal loads and electrical and thermal energy storage systems and assumes that neither renewable generation nor the electrical and thermal load demands are controllable. The EMS is built through two low-complexity FLC blocks of only 25 rules each. The first one is in charge of smoothing the power prfile exchanged with the grid, whereas the second FLC block drives the power of the Electrical Water Heater (EWH). The EMS uses the forecast of the electrical and thermal power balance between generation and consumption to predict the microgrid behavior, for each 15-minute interval, over the next 12 hours. Simulations results, using real one-year measured data show that the proposed EMS design achieves 11.4% reduction of the maximum power absorbed from the grid and an outstanding reduction of the grid power profile ramp-rates when compared with other state-of-the-art studies.
Open Access
Fuzzy-based power exchange management between grid-tied interconnected residential microgrids
(IEEE, 2020) Arcos Avilés, Diego; García Gutiérrez, Gabriel; Guinjoan Gispert, Francesc; Ayala, Paúl; Ibarra, Alexander; Motoasca, Emilia; Llanos, Jacqueline; Pascual Miqueleiz, Julio María; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This paper presents a fuzzy-based power exchange management between two neighboring residential grid-connected microgrids comprising both photovoltaic generation and battery energy storage system (BESS). The proposed power exchange management accounts for the magnitude of the energy rate-of-change of each microgrid and the charge difference between the BESSs of both microgrids to charge the ESS that has an energy deficit. As such, the proposed power exchange management can reduce the amount of power absorbed from the mains of each microgrid by operating jointly with each other rather than separately, and it also synchronizes the ESS of both microgrids, improving the behavior of ESSs. A comparison of the simulated results for a scenario with and without power exchange is presented in order to demonstrate the adequate behavior of the proposed power exchange management.
Open Access
Energy management for an electro-thermal renewable based residential microgrid with energy balance forecasting and demand side management
(Elsevier, 2021) Pascual Miqueleiz, Julio María; Arcos Avilés, Diego; Ursúa Rubio, Alfredo; Sanchis Gúrpide, Pablo; Marroyo Palomo, Luis; Ingeniería Eléctrica, Electrónica y de Comunicación; Institute of Smart Cities - ISC; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren
This paper proposes an energy management strategy for a residential microgrid comprising photovoltaic (PV) panels, a small wind turbine and solar thermal collectors. The microgrid can control the power exchanged with the grid thanks to a battery and a controllable electric water heater, which provide two degrees of freedom to the control strategy. As input data, the proposed control strategy uses the battery state of charge (SOC), the temperature of the hot water tank, the power of each microgrid element as well as the demand and renewable generation forecasts. By using forecasted data and by controlling the electric water heater, the strategy is able to achieve a better grid power profile while using a smaller battery than previous works, hence reducing the overall cost of the system. The strategy is tested by means of simulation with real data for one year and it is also experimentally validated in the microgrid built at the Renewable Energy Laboratory at the UPNA.
Open Access
In-field energy performance of solar PV module made of UMG silicon
(IEEE, 2022) Guerra Menjívar, Moisés Roberto; Parra Laita, Íñigo de la; García Solano, Miguel; Pascual Miqueleiz, Julio María; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoaren eta Telekomunikazio Ingeniaritzaren; Institute of Smart Cities - ISC
Upgraded metallurgical grade silicon (UMG-Si) PV modules have failed to make their space in the PV market, which was partly to the uncertainty on their in-field performance that brings the wide disparity of results published over the years. The most-recently developed UMG-Si PV modules have demonstrated similar initial degradation and efficiencies under standard test conditions (STC) to those obtained with conventional solar grade silicon (SoG-Si). Nevertheless, their performance under operating conditions other than STC and its impact on the energy production are key aspects that have not yet been properly characterized in the literature. This article analyzes the in-field performance of a PV generator comprised of recently developed UMG-Si modules. This performance was compared to that of another PV generator comprising standard polysilicon modules. The cells and modules of both types of generators were made by the same manufacturer in the same period and on the same production lines, which guarantees that performance differences encountered are exclusively due to the silicon employed. Contrary to the previous experience, this article reveals that UMG-Si modules do not necessarily present a better temperature performance than today's conventional modules. The analyzed UMG-Si modules presented 1.6% less efficiency under low irradiance conditions, but this different irradiance performance led to an insignificant difference (less than 0.5%) in their energy production. No significant degradation was measured in both UMG-Si and SoG-Si modules during the two-year analyzed period, being the final energy performance of both types of modules essentially the same. These results can be considered as highly representative of the current state-of-the-art of UMG-Si technology.
Open Access
Integration of wind and PV power in the spanish electric system using existing hydroelectric power
(IEEE, 2024-08-30) Garwa, Asheem; Pascual Miqueleiz, Julio María; Marroyo Palomo, Luis; Ingeniería Eléctrica, Electrónica y de Comunicación; Ingeniaritza Elektrikoa, Elektronikoa eta Telekomunikazio Ingeniaritza; Institute of Smart Cities - ISC
This paper analyses the potential reduction of electric energy generated with fossil fuels with 40 GW of PV power and 40 GW of wind power in the existing Spanish electric system and its integration by making use of existing hydroelectric power and reserves with different levels of flexibility. We use 10-minute data for 2 years and we firstly assume that hydro power remains the same as originally, observing an already high reduction in fossil fuel use in the electric mix. Then we increasingly allow more flexibility in hydro power use, i.e., we allow to use hydro reserves with different time horizons, and we analyze the incremental reduction in fossil fuel generation as we increase this flexibility. We observe that we can obtain notable gains in terms of fossil fuel reduction when increasing flexibility just slightly showing how hydro power can integrate large amounts of variable renewable energy in Spain with only a small change in the reserves profile.