Search results for "Converter"
showing 10 items of 275 documents
An Innovative Wave Energy Converter in the Mediterranean Sea
2018
The paper proposes a revolutionary device for the utilization of a new entry of renewable energy sources: sea wave. This technology is based on linear generators, able to converts directly a linear motion into electrical output, limiting to minimum the chain of energy conversion. A preliminary feasibility study considers a case study, applied in Lampedusa, a small island in the Mediterranean Sea. Economic and environmental assessments are reported.
Stochastic modeling and prediction of catalytic converters degradation
2009
This paper proposes a stochastic model for describing the degradation process of catalytic converters over time, where the degradation is indirectly measured through the emission of complex hydrocarbons (HC) in legislated driving cycles. The proposed model is the superposition of two processes, the former being a dependent increments process which describes the actual degradation process, and the latter a white noise process which models the experimental errors. In particular, the proposed model assumes that the degradation growth in a small usage interval depends on the degradation level at the beginning of the interval, rather than on the age of the converter. The model has been applied t…
Towards an AMTEC-like device based on non-alkali metal for efficient, safe and reliable direct conversion of thermal to electric power
2018
Alkali Metal ThermoElectric Converters directly convert heat into electric energy and have promising applicability in the field of sustainable and renewable energy. The high theoretical efficiency, close to Carnot's cycle, the lack of moving parts, and the interesting operating temperature range drive the search for new materials able to ensure safe and reliable operation at competitive costs.The present work focuses on the design of a non-alkali metal based cell and on the fabrication of a testing device to validate the design work. The selection of a new operating fluid for the cell improves durability, reliability and safety of the device. Finally, we discuss possible applications to alr…
Phase-Noise and Amplitude-Noise Measurement of DACs and DDSs
2019
This article proposes a method for the measurement of Phase Noise (PN, or PM noise) and Amplitude Noise (AN, or AM noise) of Digital-to-Analog Converters (DAC) and Direct Digital Synthesizers (DDS) based on modulation-index amplification. The carrier is first reduced by a controlled amount (30-40 dB) by adding a reference signal of nearly equal amplitude and opposite in phase. Then, residual carrier and noise sidebands are amplified and sent to a conventional PN analyzer. The main virtues of our method are: (i) the noise specs of the PN analyzer are relaxed by a factor equal to the carrier suppression ratio; and, (ii) the capability to measure the AN using a PN analyzer, with no need for th…
A Bidirectional Converter for the Integration of LiFePO4 Batteries with RES-based Generators Part I: Revising and Finalizing Design
2014
This paper presents a device for controlling and connecting combined Renewable Energy Sources (RES)-based generators and electric storage systems to the supply utility grid. The device is a bidirectional converter that can be controlled in order to facilitate the interface between the low voltage grid and small generators combined with lithium-ion LiFePO4 batteries, contemporary addressing the requirements of the reference technical standards for users connection and providing different ancillary services. The paper describes the revising and finalizing activities carried out by the DEIM of the University of Palermo and ENEA during 2013.
Preliminary test on a cascode switch for high-frequency applications
2020
Nowadays, an increasing electrification level is being addressed towards different sectors, such as transportation and industrial electronics. To bear that, high speed electrical machines represent a mature technology in different application fields, e.g. avionics, automotive, compressors and spindles. In order to guarantee high speed while keeping high power quality without adopting bulky filtering circuits, DC-AC converters shall be controlled by means of high Pulse Width Modulation (PWM) frequencies. In addition to the emerging switching device technologies, such as those based on Silicon-Carbide (SiC) and Gallium-Nitride (GaN), alternative circuital topologies are crucial in order to co…
Overview and experimental analysis of MC SPWM techniques for single-phase five level cascaded H-bridge FPGA controller-based
2016
This paper presents an overview and experimental analysis of the MC SPWM techniques for single-phase cascaded H-bridge inverter. The multilevel power converters are an alternative to traditional converters known as “three-level converters”. The voltage waveforms and the related frequency spectra, which have been obtained by simulation analysis in Matlab-Simulink environment, are here reported for all the proposed modulation techniques. The simulation results have been experimentally validated through means of a DC/AC, five-level, single-phase converter prototype with an appropriate test bench.
Optimization of a Time-to-Digital Converter and a coincidence map algorithm for TOF-PET applications
2015
This contribution describes the optimization of a multichannel high resolution Time-to-Digital Converter (TDC) in a Field-Programmable Gate Array (FPGA) initially capable of obtaining time resolutions below 100ps for multiple channels. Due to its fast propagation capability it has taken advantage of the FPGA internal carry logic for accurate time measurements. Furthermore, the implementation of the TDC has been performed in different clock regions and tested with different frequencies as well, achieving improvements of up to 50% for a pair of channels. Moreover, since the TDC is potentially going to be used in a trigger system for Positron Emission Tomography (PET), the algorithm for coinci…
Four Quadrant Switch Based Multiple-Input DC-DC Converter
2021
In this paper, a novel non-isolated multiple input dc-dc converter (MIC) is proposed. The MIC uses four-quadrant switches, only one inductor and capacitor. It is capable of bidirectional operation in non-inverting buck-boost configuration and can accommodate the simultaneous transfer of energy from more than one source of different voltage levels to the DC bus. This MIC is analysed for two inputs in this paper. As compared to existing MICs in literature, the proposed converter utilizes less number of inductors and requires only one switch to integrate any extra energy storage. Different operation modes of the proposed MIC are numerically verified and validated on a high-fidelity hardware-in…
A lossless current sensing technique for flyback converters
2009
Regardless of the feedback control, almost all converters require input or output current sense for overcurrent protection. If a current mode control is implemented, high accuracy is also required. The optimal current sensing method shows the highest accuracy and the lowest power dissipation. In this paper, a lossless and accurate current sensing technique for Flyback converters is proposed. An RC network is parallel connected with the primary MOSFET and the voltage signal across the sense capacitor accurately reproduces the magnetizing current waveform. The RC technique benefits from all the advantages of the most common current sensing techniques currently applied to Flyback converters, a…