Sine Wave Filters Design for AC Motor Drives with Genetic Algorithms

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The stellar-to-halo mass relation of GAMA galaxies from 100 deg2of KiDS weak lensing data

We study the stellar-to-halo mass relation of central galaxies in the range 9.7 5 × 1010h-2M&sun;, the stellar mass increases with halo mass as ˜ {}M_h^{0.25}. The ratio of dark matter to stellar mass has a minimum at a halo mass of 8 × 1011h-1M&sun; with a value of M_h/M_*=56_{-10}^{+16} [h]. We also use the GAMA group catalogue to select centrals and satellites in groups with five or more members, which trace regions in space where the local matter density is higher than average, and determine for the first time the stellar-to-halo mass relation in these denser environments. We find no significant differences compared to the relation from the full sample, which suggests that the stellar-to-halo mass relation does not vary strongly with local density. Furthermore, we find that the stellar-to-halo mass relation of central galaxies can also be obtained by modelling the lensing signal and stellar mass function of satellite galaxies only, which shows that the assumptions to model the satellite contribution in the halo model do not significantly bias the stellar-to-halo mass relation. Finally, we show that the combination of weak lensing with the stellar mass function can be used to test the purity of group catalogues

Modelli ad alta frequenza di sistemi elettronici di potenza

Dottorato di ricerca in ingegneria elettronica. 12. ciclo. A.a. 1998-1999. Coordinatore Vincenzo Coccorese. Tutore Salvatore CocoConsiglio Nazionale delle Ricerche - Biblioteca Centrale - P.le Aldo Moro, 7 , Rome; Biblioteca Nazionale Centrale - P.za Cavalleggeri, 1, Florence / CNR - Consiglio Nazionale delle RichercheSIGLEITItal

Reduction of Conducted Electromagnetic Emissions in Multi-Inverter Drive Systems

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A Neural Network Based Behavioral Model of a Monolithic Cascode Power Switch

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Measuring Active Power as the Difference between the Peak Value of Instantaneous Power and the Apparent Power

The traditional approach to calculate the active and reactive power in AC power systems requires the measurement of the phase shift between the voltage and current for the evaluation of the power factor. To do this, power analyzers can implement several methods. In principle, it is always necessary to identify specific points of waveforms (e.g., using a zero-crossing detection technique) and get their time shift. In a similar way, the frequency value must be evaluated in order to calculate the angular frequency. Unfortunately, this kind of common method exhibits some issues, such as the large sensitivity to noise. Moreover, inaccuracies in the evaluation of the power factor have a big impact on the final estimation of the electric power. This paper presents a simple but effective way to calculate the electric power, overcoming the need for a direct measurement of the phase shift and frequency. In particular, it is shown that the active power can be easily calculated as the difference between the peak value of the instantaneous power and apparent power. The reactive power and power factor are evaluated by exploiting the same quantities. The practical implementation of the proposed formulation in power analyzers guarantees several benefits without reducing accuracy

Sine Wave Filters Design for AC Motor Drives with Genetic Algorithms

This paper proposes a suitable design methodology of the filter used at the output of inverters for AC motor drives. While it allows to achieve the best tradeoff among different design constraints that are difficult to include in standard design methods, such an approach is able to simultaneously consider several technical issues such as losses and voltage drops of the filter, total harmonic distortion of currents and voltages as well as economic aspects. Accordingly, the proposed procedure determines the optimal values of the filter parameters by exploiting simulations of accurate model of the electrical drive and genetic algorithms. Hence, no rough approximations or complex analytical calculations are performed to suitably design the inverter output filter. The method was validated by means of various tests performed on two different induction motor drives, considering some significant design constraint scenarios

A High Efficiency Interleaved PFC Front - End Converter for EV Battery Charger

Nowadays, an increasingly present application in the automotive field is the battery charger that usually consists of two high efficiency parts: an AC/DC converter with power factor correction (PFC) capability and a DC/DC converter. In this paper, a three-channel interleaved Power Factor Correction (PFC) based on a new digital controller STNRGPF01 operating in Continuous Conduction Mode (CCM) is presented addressing high efficiency. In the considered applications, the most challenging control issues are the input current control and the fast overcurrent protections. Exploiting mixed signal control approach some benefits have been obtained and confirmed by experimental results on a 3 kW prototype

Multi-Criteria Experimental Comparison of Batteries Circuital Models for Automotive Applications

Electrochemical batteries used in energy storage systems provide a significant contribution to the development of smart grids and green transportation. In recent years, intensive research activities have been oriented to the optimal management of energy storage systems for power electronics applications in fast growing industrial sectors as EVs and HEVs. The accurate modeling of electrochemical batteries is fundamental in the design of control algorithms applied to energy storage systems. Focusing on automotive applications, in this paper a comprehensive analysis of ESS models based on equivalent electric circuits using a multi-criteria approach is presented. An extensive experimental validation has been carried out to evaluate the performance of battery models in automotive applications