Stanimir Valtchev

n/a

n/a

The research on the solar concentrating equipment is intensified in the recent years in many scientific and industry groups and institutions. This growing interest is based mainly on the higher efficiency and lower investment in material that is typical for this solar technology. This work started not to answer a market problem but with the idea of development a new application for an domestic size collector of line-focussing Fresnel collector. Which is will be a important step for the renewable energy. If successful, in a few years a common person will be ready to produce solar thermoelectricity at home with the double benefit of producing electricity and hot steam. The paper presents a design methodology and heat transfer calculation for an concentrating system based on the Linear Fresnel Reflector (LFR) concept. The basic absorber design is an trapezoidal inverted air cavity without glass cover. The absorber is covered with a selective surface and is oriented north- south. This arrangement has shown good optical and thermal performance results validated by measurements during outdoor tests.

n/a

n/a

n/a

n/a

n/a

n/a

This paper describes the theoretical and experimental results achieved in optimizing the application of the series loaded series resonant converter for contactless energy transfer. The main goal of this work is to define the power stage operation mode that guarantees the highest possible efficiency. The results suggest a method to select the physical parameters (operation frequency, characteristic impedance, transformer ratio, etc.) to achieve that efficiency improvement. The research clarifies also the effects of the physical separation between both halves of the ferromagnetic core on the characteristics of the transformer. It is shown that for practical values of the separation distance, the leakage inductance, being part of the resonant inductor, remains almost unchanged. Nevertheless, the current distribution between the primary and the secondary windings changes significantly due to the large variation of the magnetizing inductance. An approximation in the circuit analysis permits to obtain more rapidly the changing values of the converter parameters. The analysis results in a set of equations which solutions are presented graphically. The graphics show a shift of the best efficiency operation zone, compared to the converter with an ideally coupled transformer. Experimental results are presented confirming that expected tendency.

n/a

n/a

The electromagnetic resonance became irreplaceable tool for wirelessly transfer energy and information. Since long this effect is widely used in communications but recently it is deeply studied and applied at the contactless transfer of energy. The electric/hybrid car battery charging is an urgent need and the knowledge about the resonant contactless transfer became very important. The study of the Series Loaded Series Resonant converter shows it as well suitable for the contactless energy transfer. The idealized Series Resonant Power Converter is used as a base for defining the best (most efficient) modes of operation. Based on the magnetic parameters of the loosely coupled transformer (magnetic link), the characteristics of the contactless power converter are described in approximated form, thus permitting an easier and faster calculation of the converter variables. This is used for instantaneous control of the converter, free from previously known defects.

The electromagnetic resonance became irreplaceable tool for wirelessly transfer energy and information. Since long this effect is widely used in communications but recently it is deeply studied and applied at the contactless transfer of energy. The electric?hybrid car battery charging is an urgent need and the knowledge about the resonant contactless transfer became very important. The study of the Series Loaded Series Resonant converter shows it as well suitable for the contactless energy transfer. The idealized Series Resonant Power Converter is used as a base for defining the best (most efficient) modes of operation. Based on the magnetic parameters of the loosely coupled transformer (magnetic link), the characteristics of the contactless power converter are described in approximated form, thus permitting an easier and faster calculation of the converter variables. This is used for instantaneous control of the converter, free from previously known defects.

n/a

n/a

n/a

n/a

n/a

n/a

n/a