1,721,074 research outputs found
An Example of Modelica–LabVIEW Communication Usage to Implement Hardware-in-the-Loop Experiments
No full textCaratterizzazione in Frequenza e Modellazione di Supercondensatori per Applicazioni in Veicoli Ibridi
No full textCaratterizzazione Sperimentale delle Proprietà di Accommodation di Materiali Magnetici Dolci utilizzando Traiettorie Complesse
No full textAnalysis of the possible impact of complex bids in the Italian electricity spot market
No full textThe liberalization of the electricity market, already affirmed in many European and worldwide countries, has originated many technical debates over the definition of the market model that can be considered as optimal for electricity. The required simplicity and transparency of market rules often contrast with the intrinsic complexity of the electrical system, due to physical and security requirements. For these reasons, issues related to the mechanism for bid selection in the energy market are one of the most debated during the phase of market rules definition.
In this paper, we present an analysis of the possible quantitative impact of complex bids in the Italian electricity day-ahead market, in order to evaluate benefits and drawbacks
Clearing procedures for day-ahead Italian electricity market: are complex bids really required?
No full textMany technical debates discussed in the last years the market structure that can be considered as optimal for electricity in a deregulated environment. Simplicity and market transparency do not always comply with the intrinsic complexity of the electrical system, due to technical constraints and security requirements. The mechanism for bid selection in the day-ahead market is one of the most discussed topics, because it strongly influences both the economical revenues of operators and the physical feasibility of the dispatching schedules set by the market.
Usual production bids, only detailing hourly prices and quantities (“simple bids”), do not transfer to the clearing mechanism important technical-economical integral constraints, like the minimum daily revenue required by the operator or the power ramp limitation of generating units; in this case, adjustment sessions follow the primary energy market, to correct undesired or unfeasible outcomes.
In some markets, such additional constraints are already expressed in the so-called “complex bids”, thus avoiding or minimizing the need for adjustment sessions. Nevertheless, the clearing mechanism of the day-ahead market results strongly complicated and the system transparency decreases; the effectiveness of this solution must be then carefully assessed.
In this paper, we present an analysis of the possible quantitative impact of complex bids in the Italian electricity day-ahead market, in order to evaluate possible benefits and drawbacks
Hysteresis Losses of Minor Loops vs. Temperature in MnZn Ferrite
No full textThis paper analyzes hysteresis losses of minor loops versus temperature in MnZn ferrite core. The study is carried out through an experimental analysis in the temperature range-32°C to +110° C. The most interesting result is a nonmonotonic behavior of losses versus temperature for minor loops defined between magnetic field relatively close around the zero value. Such a result is qualitatively explained on the basis of a competition between exchange energy and magnetic anisotropy. In more detail, the relationships between permeability and exchange energy as well as coercivity and magnetic anisotropy are discussed via recognized models
Experimental Analysis of Shielding Performance in Rail-Launcher Environment
No full textIn this paper we develop an experimental analysis aimed at characterizing the shielding performance of shields operating in electromagnetic rail launchers. The experimental analysis is carried out for various shield configurations and different materials. In particular, cylindrical shell cylinders are adopted. The experiments are performed on a rail launcher prototype supplied by a high pulsed power device. Finally, we make some remarks on the measurement of the shielding effectiveness in such critical environments
A New Approach for Characterizing the Energetic Magnetic Behavior of Fe-9Cr Steel Under Transient Conditions
No full textThe aim of this paper is to evaluate the magnetic properties and losses of the Fe-9Cr steel under nonperiodic conditions of the magnetic field. A new approach combining an optimized linear problem and properties of the classical Preisach theory is adopted and described. An experimental analysis is carried out to characterize quasi-static major loop and dynamic cycles obtained at different rate of the driving magnetic field H. After a series of quasi-static major loops, dynamic cycles are defined in a first case varying H from the saturation to its opposite value and in a second case forming minor asymmetric loops. In both the cases, hysteresis and eddy current losses are estimated via the proposed method. Total losses are compared with measurement results to validate the procedure
Analytical study of high pulse current shunts
No full textIn this paper we reapproach the study of current shunts via analytical way, focusing on high pulse current applications such as electromagnetic rail launchers. Through the use of the partial mutual inductance method we revisit some design aspects in order to increase the shunt bandwidth and the bandwidth of the measurement circuit. The inductance expression of a ‘squirrel cage’ shunt is derived and tested on a homemade prototype. The experimental results confirm the validity of the model and its robustness with respect to the geometrical parameter uncertainty
Analytical Study of Impulse Current Measuring Shunts With Cage Configuration
No full textIn this paper, an analytical study of high-impulse current measuring shunts with cage configuration is presented. Through the use of the partial mutual inductance method, an equivalent first-order model is developed, and a discussion of the minimization of the time constant taking into account physical constraints for two different materials is presented. The transfer function of the measuring circuit is provided, and the possibility of compensating the inductance via the use of rectangular loops formed by the sensing wires and placed inside the cage is shown. The derived model is tested on a homemade shunt prototype with application to an electromagnetic rail launcher. The experimental results confirm the validity of the model and its robustness with respect to the geometrical parameter uncertainty
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