1,720,962 research outputs found
Characterization of a CPV module prototype for design and performance improvement
No full textThe purpose of this paper is to highlight that a detailed electrical and optical characterization is a basic step to improve the design of a concentrating photovoltaic (CPV) module and enhance its overall performance. The complete characterization of the preliminary CPV module prototype, designed according the state of art, has been carried out revealing lower performances than expected. The reasons of the energy losses have been determined by an accurate optical and electrical analysis. The results of these tests permitted to introduce upgrades into the design of a second version of the CPV module in order to overcome the main defects previously identified. The full characterization of this new version revealed significantly higher performances. Overall, the obtained outcomes demonstrate the benefits of an accurate characterization, allowing both the identification of the system problems design and the evaluation of the effects of the adopted solutions
A Concentrator Photovoltaic Panel Prototype: Realization and Characterization
No full textIn this paper the prototype of concentrator photovoltaic (CPV) panel with Fresnel lenses primary optical elements has been characterized. The module has been developed by the National Institute for Astrophysics (INAF) of Cagliari. The testing and characterization process has been developed at the Sardegna Ricerche PV Laboratory. The optical and mechanical design of the proposed CPV module is firstly reported. Afterwards the outdoor testing results are presented. Most of panel components have been characterized in order to understand the weight of each element on the energy conversion process and on energy efficiency. In particular, the performances of primary and secondary optical elements, photovoltaic multi-junction cell and solar receiver heat sink have been assessed. A special attention has been paid to the evaluation of the module angle acceptance and to the analysis of the spatial distribution of the concentrated solar radiation on the cell plane in order to understand the influence of tracker accuracy and irradiance non-uniformity on the CPV prototype electrical performances. The characterization activity has been completed with an accurate analysis of the meteorological conditions measurements at the Sardegna Ricerche outdoor Photovoltaic Laboratory test bench, in order to verify the suitability of the site to the IEC 62670 standard draft
Experimental Validation of a Dynamic Energy Model of a Battery Electric Vehicle
No full textIn the present paper the electro-mechanical model of an electric vehicle suitable for battery energy management systems has been presented. In order to verify its accuracy, the comparison between the experimental and simulation results has been carried out. Particularly, the energy battery estimation of a Smart Fortwo electric vehicle has been developed. The electro- mechanical model describing the vehicle dynamic, the power- train and the transmission system have been implemented in the Matlab environment. Moreover, a detailed battery model has been introduced in order to represent accurately its static and dynamic behavior. To verify the matching of the electric vehicle model under critical energy conditions, corresponding to rapid speed changes, the experimental data of two no-standard driving paths has been collected. The comparison of the estimated battery parameters with the experimental ones has been finally reported highlighting a good matching between them
Optimal Management Strategy of Energy Storage Systems for RES-based Microgrids
No full textAn optimal control strategy devoted to manage the daily charging/discharging profiles of energy storage systems (ESSs) is described in the present paper. The proposed approach aims at minimizing microgrids (MGs) daily electricity costs considering both the real-time prices evolution and the effects of a significant presence of intermittent RES generation. Referring to MGs and electricity market modeling, which takes into account their main physical and economic constraints, an ESS charging/discharging strategy has been developed. The effectiveness of the proposed ESS management is verified on a MG case study. The measurements of the MG demand and RES production are used to simulate and compare the daily MG electricity costs and energy balances with and without the proposed ESS optimal control
A Microgrid Energy Management System Supported by a Hysteresis Vehicle to Grid Controller
No full textIn order to support the energy management systems (EMSs) of microgrids, bidirectional current controllers for the charging stations of electric vehicles (EVs) have been investigated. For this purpose, different strategies for implementing Vehicle to Grid (V2G) have been considered. The EMS goal is to balance the energy demand and production in microgrids by maximizing the self-consumption by means of electric vehicle storage systems. In order to compare the EMS performances, two different approaches in controlling the V2G charging stations, based on continuous and hysteresis control algorithms, have been analysed. In particular, a V2G hysteresis controller with step wise constant current profiles has been designed in order to preserve the EV battery life. The proposed control algorithm has been simulated considering the actual measurements of a real microgrid char- acterised by an intermittent renewable energy overproduction. The results show the feasibility to implement V2G paradigm by means of hysteresis controller for the management of the EV charging currents with step wise constant profiles
Outdoor characterization of a Cassegrain-type concentrator photovoltaic receiver
No full textIn this study, the characterization of a concentrator photovoltaic (CPV) system based on a Cassegraintype optic is presented. The indoor and outdoor electrical parameters have been measured and analyzed. On the basis of the IEC 60891 standard, the acquired I-V characteristics have been reported under the CSTC defined in the CEI 82-25 and the electrical parameters deviations have been determined. The correlations among temperature, direct normal irradiance (DNI) and power have been discussed. The results of the absolute power test based on the ASTM E2527 standard and the values of power deviation are reported. Finally the rating power comparison between the two standard test procedures is performed
Concentrator photovoltaic standards: Experimental analyses of technical requirements
No full textThe continuing development and the increasing diffusion of concentrator photovoltaic (CPV) systems highlight the lack of specific international standards in the CPV power rating and characterization field. Presently, the only reference standard for CPV cells and modules is the IEC 62108, which does not impose minimum requirements for solar trackers and simulators used in the qualification process of CPV modules. Nevertheless, the overall quality of CPV tests is strictly associated to the technical specifications of these devices. The aim of this paper is to define optical and radiometric properties of solar simulators and the pointing accuracy of solar trackers, required for testing CPV devices and rating their performance. The results of experimental analyses on real CPV systems have been reported, highlighting the criticalities of indoor and outdoor CPV characterization. Finally an outdoor light soaking test, executed under MPPT conditions, has been proposed for the qualification process of high concentrating photovoltaic devices
A DC Side Energy Storage Management for One-Day-Ahead Power Profile Control of Concentrator Photovoltaic Power Plants
No full textIn the present paper, a concentrator photovoltaic (CPV) power plant integrated with an Energy Storage System (ESS), which is controlled in order to schedule one-day-ahead the electricity production, is presented. The proposed control algorithm is characterized by the predictive definition of output power shapes. The daily estimation of the ESS State of Charge (SoC), jointly to the measurement of its actual evolution, is used for implementing a hysteresis real-time control devoted to adapt the power profile for compensating unpredictable power fluctuation. In order to develop the proposed energy management system with an existing CPV power plant, a DC side ESS control system, characterized by the use of a bidirectional DC-DC buck-boost converter, is considered. The feasibility of the proposed CPV energy management system is verified by means of a simulation study, which is carried out using on-site CPV prototype measurements
Cost Effective HCPV Fresnel Lenses Module Prototype: Design, Performance Results, In-Field Testing and Economic Analysis
No full textIn this contribution we report on a new module prototype of high concentrator photovoltaic (HCPV). The optical design of the presented prototype is based on two optical elements: high quality Fresnel lenses and aluminum homogenizers, while for the realisation of the photovoltaic receiver a triple junction solar cell has been used. The whole device has been designed and developed as a cost effective product providing at the same time high value for the output power. Measurements aimed at determining electrical characteristics have been performed both on single concentrator cells and on the module realised by connecting together four single photovoltaic receivers. Thermographic measurements have been carried out in order to determine the zones where heating effects have occurred during the operating conditions. The paper purpose is to provide an overall presentation and accurate description of the final version of HCPV new module prototype that is the result of the collaboration of Italian National Institute for Astrophysics of Cagliari, Electrical and Electronic Engineering Department of University of Cagliari and Sardegna Ricerche Photovoltaic Laboratory
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