Ales Havel

This paper focuses on the development and optimization of a special hybrid electric vehicle arrangement known as a four-quadrant rotary converter. The introduction summarizes the main advantages and disadvantages of existing topologies in radial and axial flux arrangements. Based on previous experience, we developed a novel axial flux arrangement that eliminates the problems and disadvantages associated with existing radial flux solutions. In addition, this paper evaluates and subsequently describes the optimization of permanent magnet parameters in an axial flux rotary converter unit. A number of 3D finite element method optimizations were performed to find the optimal mass distribution of permanent magnets on the frontal area of the outer rotor in the axial flux rotary converter unit. The optimization involved the permanent magnets’ material, shape, and thickness in order to achieve maximal efficiency of the entire unit while leaving its nominal output power and speed unaffected. The results show an increase in the overall theoretical efficiency of the outer rotor unit from 90.2% to 94.4% following the optimization.

This paper deals with power semiconductor converter technology used for coupling the hydrogen-based technologies like electrolyzers and fuel cells with different types of the accumulators. The current control methods for two-phase buck-boost converter are further presented in this paper. The function of the coupling converter has been proven in both directions of current/power flow in the experimental results section.

Trend of increasing the share of electricity production from the renewable energy sources will surely continue the in the upcoming time period. This paper outlines multiple solutions of accumulation of energy, especially electricity, in the Technology Center of Ostrava (TCO). It presents solutions for storage of electrical energy into the batteries with use of power converters with an additional function of active power filtering. The paper aims primarily to familiarize the reader with the methods of controlling power converters at the basic level. It deals with the current and power regulation of individual inverters and their concepts, but not on their superior management, decision-making and control processes around the technology center.

The searching and utilization of new energy sources and technologies is a current trend. The effort to increase the share of electricity production from renewable energy sources is characteristic for economically developed countries. The use of accumulation of electrical energy with a large number of decentralized storage units is most preferred, as well as the focus on the production of energy at the point of its consumption. Modern cogeneration units are a good example. This paper describes the accumulation of electrical energy for equalizing the power balance of electric charging stations with high instantaneous power. The possibility of re-utilization of electrical energy from the charged vehicle in the case of lack of electricity in the power grid is solved at the same time. This paper also deals with the selection of appropriate concept of accumulation system and its cooperation with both renewable and distribution networks. Details of the main power components including the results obtained from the system implementation are also described in this paper.

Control of electrical power systems with attached units of accumulation represents a relatively complex problem, both in terms of technical equipment and in terms of the measurement and the control algorithms. In order to control system dynamically from the viewpoint of energy flows, so particularly with regard to increasing quality of electrical energy, all processes must be processed with relatively high frequency of sampling. The paper describes the elements of electrical energy accumulation control system, which was implemented in the Technology Centre of VřB - Technical University of Ostrava. This system uses originally developed analog measuring logger, which performs data collection from the entire system, processes the data and generates the desired quantity of them for semiconductor converters control. These converters perform control of energy flows throughout the accumulation system.

At the present time the major part of traction systems uses single-phase 25kV/50Hz or 15kV/16,66Hz circuitry to traction vehicles supply. The supply stations of traction systems were made in different ways like rotary converters, cycloconverters and actually DC-link converters. The paper compares the static converter features and introduces the new concept of current-type soft switching DC-link frequency converter. This concept uses the three-phase zero current switch pulse rectifier, current-type, as a modern input unit of current indirect frequency converters including soft switching. The converter has many advantages e.g. the low emissions of harmonic components into the mains, the controlled power factor, the convenient current control in the DC link and low switching losses. This type of converter solves some problems of EMC and can control the converter power factor on the mains side. The suitable delta modulation of the converter is also described in the paper. The measured results were done in the application of the realized pulse rectifier as the input unit of the zero current switching indirect frequency converter with the series resonant DC link.

This paper deals with the power design and operation of an 80kW, high efficient reversible voltage inverter (RVI) for electric energy accumulation based systems. The energy converter is characterized by its dynamic responses on desired energy flow direction changes and is built as a liquid cooled system. The theoretical part of this paper describes the power design of IGBT transistors and DC link capacitors, as well as the application of the 3D CAD and 3D FEM systems, which have been used for constructional arrangement designing and thermal/CFX analyses. The ripple current and thermal dimensioning of the capacitor battery was simulated in the OrCAD PSpice electronic circuit simulator. The practical part of this paper shows the utilization of whole energy converter in the accumulator switchboard, as well as the examples of converter's operation in cases of battery charging and discharging to the grid. The main practical utilization possibilities of presented device are in the renewable energy plants, active charging stations or smart grid systems targeted on the electric energy accumulation.

Comparison of Standard and Fast Charging Methods for Electric Vehicles