Search results for "IMU"
showing 10 items of 16028 documents
An Analytic Approach to the Modeling of Multijunction Solar Cells
2020
Analytic expressions for the $JV$ -characteristics of three types of multijunction configurations are derived. From these, expressions for the short-circuit current, open-circuit voltage, and voltage at the maximum power point are found for multiterminal devices, and for series-connected tandem stacks. For voltage-matched devices, expressions for the optimal ratio of the number of bottom cells to the number of top cells are established. Luminescent coupling is incorporated throughout the article. It should be highlighted that the maximum power point of a series-connected tandem stack is described, with good accuracy for all interesting band gap combinations, by a single analytic expression.…
Temperature Coefficients of Solar Cell Parameters at Maximum Power Point
2020
Analytical expressions for the temperature coefficients of the maximum power point voltage and current are presented. The temperature coefficients are calculated assuming the bandgap to be a linear function of the temperature and accounting for energy losses of non-radiative nature. The latter are introduced in the model through the External Radiative Efficiency. The so-called $\gamma$ parameter, which has been shown to account for the thermal sensitivity of all mechanisms determining the open-circuit voltage, appears to also play a role in the temperature coefficient of the maximum power point voltage and current. Numerical results and a comparison with experimental measurements are also p…
Charge breeding at GANIL: Improvements, results, and comparison with the other facilities
2019
International audience; The 1+/n+ method, based on an ECRIS charge breeder (CB) originally developed at the LPSC laboratory, is now implemented at GANIL for the production of Radioactive Ion Beams (RIBs). Prior to its installation in the middle of the low energy beam line of the SPIRAL1 facility, the 1+/n+ system CB has been modified based on the experiments performed on the CARIBU Facility at Argone National Laboratory. Later, it has been tested at the 1+/n+ LPSC test bench to validate its operation performances. Charge breeding efficiencies as well as charge breeding times have been measured for noble gases and alkali elements. The commissioning phase started at GANIL in the second half-y…
Simulations on time-of-flight ERDA spectrometer performance
2016
The performance of a time-of-flight spectrometer consisting of two timing detectors and an ionization chamber energy detector has been studied using Monte Carlo simulations for the recoil creation and ion transport in the sample and detectors. The ionization chamber pulses have been calculated using Shockley-Ramo theorem and the pulse processing of a digitizing data acquisition setup has been modeled. Complete time-of-flight–energy histograms were simulated under realistic experimental conditions. The simulations were used to study instrumentation related effects in coincidence timing and position sensitivity, such as background in time-of-flight–energy histograms. Corresponding measurement…
THE GYROTRON STARTUP SCENARIO IN THE SINGLE MODE TIME DEPENDENT APPROACH
2019
The paper explains how to solve the Gyrotron equation system in the Single Mode Time Dependent Approach. In particular, we point out problems encountered when solving these well-known equations. The starting current estimation approach a using time model is suggested. The solution has been implemented in the Matlab code, which is attached to the article.
Defect-induced blue luminescence of hexagonal boron nitride
2016
Abstract Native defect-induced photoluminescence around 400 nm (blue luminescence - BL) was studied in hBN materials with different size and various origins. The following spectral characterizations were used: spectra of luminescence and its excitation, luminescence dependence on temperature, luminescence kinetics, optically stimulated luminescence and infrared absorption. It was found, that the BL is characteristic for all these materials, which were studied. The BL forms a wide, asymmetric and phonon-assisted emission band at 380 nm. This luminescence can be excited either through the exciton processes, or with light from two defect-induced excitation bands at 340 nm and 265 nm. It was fo…
Experimental comparison of two control algorithms for low-saliency ratio interior permanent magnet synchronous motors
2018
In this paper, an experimental investigation on the comparison between the Maximum Torque Per Ampere (MTPA) and the Field Orientation Control (FOC) algorithms for interior permanent magnet synchronous machines (IPMSMs) is described, analyzed and discussed. This investigation was carried out on a small-power IPMSM with low saliency ratio. More in detail, after a previous simulation study, the control techniques have been experimentally implemented and validated through means of a dSPACE® rapid prototyping system. The performances of the two algorithms have been evaluated and compared, obtaining interesting results.
Space‐vector state dynamic model of SynRM considering self‐ and cross‐saturation and related parameter identification
2020
This study proposes a state formulation of the space-vector dynamic model of the Synchronous Reluctance Motor (SynRM) considering both saturation and cross-saturation effects. The proposed model adopts the stator currents as state variables and has been theoretically developed in both the rotor and stator reference frames. The proposed magnetic model is based on a flux versus current approach and relies on the knowledge of 11 parameters. Starting from the definition of a suitable co-energy variation function, new flux versus current functions have been initially developed, based on the hyperbolic functions and, consequently, the static and dynamic inductance versus current functions have be…
Quantification of relaxor behavior in (1 − x)Na0.5Bi0.5TiO3 – xCaTiO3 lead-free ceramics system
2019
Abstract This work examines the relaxor behavior of lead-free ceramic (1 − x)Na0.5Bi0.5TiO3–xCaTiO3 systems. A stable rhombohedral (R3c) phase is detected at room temperature for all compositions by XRD and Raman spectroscopy. Relaxor behavior was observed in the temperature range 300 K - 400 K for all materials. Ceramics exhibit normal ferroelectric properties at room temperature, and then they develop relaxor characteristics with increasing temperature showing the same dispersive properties. This work quantifies the relaxor phenomenon at low temperature. For instance, the maximum temperature of relaxor and the order of dispersion were determined at the strongest dispersion. Finally, the s…
High-Resolution Stimulated Raman Spectroscopy and Analysis of the ν1 Stretching Band of GeD4
2007
The high-resolution stimulated Raman spectrum of the ν1 band of GeD4 with natural isotopic abundance germanium has been recorded. It has been analyzed as part of the ν1/ν3 stretching dyad. The ν1 and ν3 band centers have been deduced for all the isotopologues. Copyright © 2006 John Wiley & Sons, Ltd.