In this paper, the spectra of electron beams produced in vacuum and gas diodes were analyzed to study the capabilities and limitations of their reconstruction from beam attenuation in foils of different thickness. The electron energy distributions were calculated using the Tikhonov regularization for Fredholm integral equations on minimum a priori assumptions. The spectra reconstructed in the study were those of electron beams, including a supershort avalanche electron beam, produced in experiments on a DUET plasma-cathode electron accelerator and SLEP-150M accelerator.

Recent trends in building energy systems such as local renewable energy generation have created a distinct demand for energy storage systems to reduce the influence and dependency on the electric power grid. Under the current market conditions, a range of commercially available residential energy storage systems with batteries has been produced. This paper addresses the area of energy storage systems from multiple directions to provide a broader view on the state-of-the-art developments and trends in the field. Present standards and associated limitations of storage implementation are briefly described, followed by the analysis of parameters and features of commercial battery systems for residential applications. Further, the power electronic converters are reviewed in detail, with the focus on existing and perspective non-isolated solutions. The analysis covers well-known standard topologies, including buck-boost and bridge, as well as emerging solutions based on the unfolding inverter and fractional/partial power converters. Finally, trends and future prospects of the residential battery storage technologies are evaluated.

-Renewable energy sources and energy storage devices are becoming more popular. Some of them like small hydropower turbines, wind turbines and diesel generators produce AC voltage with different frequency and voltage than the main grid. For them power electronics converters are necessary. Power electronics converters presented in industry use two or three level energy conversion, although direct AC to AC converters exist, but one of the main problems is the switch commutation when current or voltage is crossing the zero point. Zero crossing sensors are used to solve this problem. They consist of current or voltage measurement unit and zero crossing detector. Different approaches are used for zero crossing: hardware or software. Hardware approach is simple but it has low precision. Software approach has high precision but it is complicated and expensive. In this paper a simple low cost high precision approach is presented. It takes all advantages from both approaches. While tested with two types of microcontrollers the precision of experimental measurement is 25 µs -40 µs.

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In electron sources with grid plasma cathodes, the boundary of the emission plasma is stabilized by a fine-structured grid, the cell size of which is comparable to the size of the Langmuir layer. The correct choice of the cell size of the emission grid allows to stabilize of the emission plasma boundary, reaching a wide range of the parameters adjustment of the generated electron beam with a weak dependence of these parameters on each other. Since the beam current amplitude is most often controlled by a proportional change of the discharge current in the plasma cathode, which allows to change the emission plasma concentration, this paper is investigated the possibility of generating the electron beam having variable amplitude by predicting the change in the discharge current amplitude during its pulse. The described advantage of plasma cathodes makes it possible to obtain electron beams with both a falling and a rising current amplitude of the beam during its pulse. The obtained regimes of electron beam generation open up new possibilities for using this source for both scientific and technological purposes.