Search results for "elettrotecnica"
showing 10 items of 338 documents
Different scenarios of electric mobility: Current situation and possible future developments of fuel cell vehicles in Italy
2020
The diffusion of electric vehicles in Italy has started but some complications weight its spread. At present, hybrid technology is the most followed by users, due particularly to socioeconomic factors such as cost of investment and range anxiety. After a deep discussion of the Italian scenario, the aim of the paper is to recognize whether fuel cell technology may be an enabling solution to overcome pollution problems and respect for the environment. The opportunity to use fuel cells to store electric energy is quite fascinating&mdash
Experimental investigation and characterization of innovative bifacial silicon solar cells
2019
The interest towards bifacial PV technology has increased over the last years, due to its potential capability of obtaining higher efficiencies with respect to traditional monofacial cells. Thus, the aim of this work is to present an experimental investigation on an innovative photovoltaic technology, such as the bifacial solar cells based on monocrystalline substrate. This analysis is mainly based on the determination of the current density/voltage, power density/voltage, External Quantum Efficiency (EQE) and Laser Beam Induced Current (LBIC) characterization. Interesting results are presented and discussed, demonstrating that the bifacial silicon solar cells can be a very promising techno…
ADVANCED BIO-ELECTROMAGNETIC NUMERICAL MODELLING AND ICT FOR HUMAN BRAIN RESEARCH
2016
Functional imaging is used in the research area neurological, neurophysiology and cognitive psychology, for the diagnosis of diseases metabolic and for the detection of thin / squamous lesions (eg Alzheimer's disease) and for the development of neural interfaces (brain-computer interfaces - BCI).
Experimental Evaluation of Dead-Time Impacts on the Efficiency and THD for a Three-Phase Five-Level Cascaded H-Bridge Inverter
2022
Cascaded H-Bridges Multilevel Inverter (CHBMI) is a fascinating solution for optimization purposes in several application fields. The CHBMI performance optimization can be reached both with hardware and software solutions. In detail, the CHBMI performances are a function of the modulation strategy adopted and its parameters such as modulation index, switching frequency, and dead time. This paper presents performance experimental analysis on dead time effects on CHBMI performance in terms of harmonic distortion and conversion efficiency. In this analysis, two different modulation strategies have been considered and implemented. The paper focuses on modulation strategies implemented, the test…
Comparison among different rainfall energy harvesting structures
2018
In this paper, an experimental comparison between different rainfall harvesting devices through the study of the electrical rectifying circuit is proposed. In more detail, three harvesting structures are considered: the cantilever, the bridge and the floating circle. Different waveforms were acquired and discussed. The processed data were compared in order to suggest the best choice for the rectifying circuit, from the simplest one to that most frequently endorsed in the technical literature.
High Frequency Model of PV Systems for the Evaluation of Ground Currents
2012
A high frequency model of a photovoltaic (PV) plant is developed and analysed to investigate the common mode (CM) currents circulating through the ground connections of the plant. The modelling method is based on the measurement of the impedance frequency response of photovoltaic module and on a high frequency representation of the power conversion unit. An overall lumped parameters circuit model is obtained and then implemented in PSpice. The CM leakage currents are evaluated by simulation.
Evaluation of ground currents in a PV system with high frequency modeling
2018
In this work a high frequency model of a photovoltaic (PV) plant is identified and implemented aiming to investigate the common mode (CM) currents circulating through the ground connections of the plant. From the identification of the impedance obtained by frequency response of photovoltaic module and by a suitable of the power conversion unit, an equivalent high frequency circuit representation has been developed. The lumped parameters circuit model is implemented in PSpice environment to obtain the CM leakage currents. Harmonics at frequencies multiple of the switching frequency and a strong resonance at about 12 MHz are detected.
Day-ahead forecasting for photovoltaic power using artificial neural networks ensembles
2016
Solar photovoltaic plants power output forecasting using machine learning techniques can be of a great advantage to energy producers when they are implemented with day-ahead energy market data. In this work a model was developed using a supervised learning algorithm of multilayer perceptron feedforward artificial neural network to predict the next twenty-four hours (day-ahead) power of a solar facility using fetched weather forecast of the following day. Each set of tested network configuration was trained by the historical power output of the plant as a target. For each configuration, one hundred networks ensembles was averaged to give the ability to generalize a better forecast. The train…
A new approach to partial discharge detection under DC voltage
2018
The continuing development of HVDC power transmission systems presents many problems related to evaluation of the reliability of power system assets [1]-[5]. In this context the identification of insulation defects plays a key role in preventing unexpected failures of electrical components. Partial discharge (PD) measurement is a useful approach to assessing the condition of HV power apparatus and cables. Such measurements are also widely employed for HVAC systems. The inception mechanisms of PD in AC systems are well-known, and measurements are usually performed following the IEC 60270 standard [6]. PD measurements under DC voltage present complexities related to the nature of the phenomen…
Performance Evaluation of a Three- Phase Five-Level Quasi-Z-Source Cascaded H-Bridge for Grid-Connected Applications
2018
In the field of the PV generation, Quasi-Z-source cascaded H-bridge (qZS-CHB) inverters are promising due to their features of modularity and high voltage conversion ratio. Thus, new topology structures and innovative modulation techniques are continuously being developed to improve the performance in terms of voltage stress and harmonic content. This paper proposes an innovative modulation technique that allows reducing the voltage stress and a specially designed grid-connected control strategy is also introduced. Through simulations in MATLAB, it has been validated that the performance of a three-phase five-level qZS-CHB is improved with the proposed solution.