Auswahl der wissenschaftlichen Literatur zum Thema „Optimalizace účinnosti“

This thesis focuses on optimization and increasing the efficiency of high-power DC/DC switching converters with transformer (switching power supplies). The work focuses mainly on using converters with flyback topology for high power, even though it is a common belief that this type of converter is not suitable for high power. This topology was selected because of potentially better achievable parameters, especially the efficiency, in comparison to a commonly used forward converter – in a flyback converter, losses are produced only in one magnetic component (transformer) in contrast to two components (transformer and inductor) in the forward converter. Compared to resonant and quasi-resonant converters, the flyback converter is easily controllable in the whole output voltage and current range. To make the flyback converter favorable for a high-power use, some innovative circuit modifications were made and modern semiconductor and passive components were used. Theoretical part of the work deals with efficiency optimization of the flyback converter, based on analytical solution. Operating parameters of the converter – switching frequency and parameters of the transformer (flux density and numbers of turns) are commonly only guessed or chosen from experience. The objective of this part is a mathematically exact determination of these parameters to achieve lowest total losses of the converter for given input parameters. In a certain case, it was possible to obtain the final solution analytically, in other cases the final solution step had to be done with a help of software. A prototype of a 12-kW switching power supply with a flyback converter was constructed to validate the proposed solutions and methods. The power supply fits into a space of only 33x33x16 cm. Modern semiconductors based on the silicon-carbide (SiC) technology (MOS-FET transistors and diodes) were used. After bringing the converter to a full-power operation, an efficiency of 96.8 % of the DC/DC converter was measured. High efficiency was obtained for a wide range of output parameters. A certain comparison with a forward converter with the same output parameters is done in the work. Not only from an efficiency point of view, the flyback converter seems very perspective.

Corrosion of steel reinforcement in concrete structures poses a risk reduction of durability and ability to perform the required function of structures for which they were designed.The objective of this work was to study the effectiveness of a new type of corrosion inhibitor with different concentrations of the active substance and its comparison with commercial products. The corrosion inhibitors were part of a comprehensive system repair materials from Betosan s.r.o. and using the electrical measurements was studied their effect in reducing corrosion activity caused by aggressive chloride environments.

This thesis is dedicated to efficiency increase of one phase induction machine through material change of induction cage and rotor slot shape optimization under the condition of maintaining the same locked-rotor torque. In the first part of this thesis is the explanation of induction machine principles. Next is the comparison of measured and simulated parameters of small one phase machine from ATAS company. The following part is dedicated to the analysis of rotor slot shape and ring size influence on machine parameters when using pure aluminum instead of resistive alloy. The next chapter deals with slot shape optimization in the program RMxprt, controlled by genetic algorithm written in MATLAB interface. In the final part are the resultant slot shapes simulated in Ansys Maxwell using finite element method and then the measured, simulated and expected parameters are compared.

The goal of this thesis is to improve efficiency of an induction motor. In the first part, the working principle is described. The next part deals with the origin of losses and possible solutions to decreasing losses without impacting the production possibles. The third part of the thesis is focused on the calculation of parameters of a small serial production motor. In the fourth part, these parameters are verified using the analytical tool RMxprt which is included in Ansys Maxwell. The fifth chapter deals with the optimization using Matlab genetic algorithm. In the final chapter, the design modifications are verified using the method of finite element Ansys Maxwell 2D.

The diploma thesis deals with the simulation of induction motor control with respect to high efficiency. The theory of an induction motor is described here, with emphasis on its losses. Scalar and vector control are also described here. Vector control is optimized for higher efficiency. Subsequently, the creation of a model in the program đť‘€đť´đť‘‡ đťżđť´đťµâ’𝑆𝑖𝑚𝑢𝑙𝑖𝑛𝑠is described here, for the comparison of scalar and vector control with optimization.

The thesis presents methods and criteria for creation and optimization of design of computer experiments. Using the core of a program Freet the optimized designs were created by combination of these methods and criteria. Then, the suitability of the designs for statistical analysis of the tasks vith input random variables was assessed by comparison of the obtained results of six selected functions and the exact (analytically obtained) solutions. Basic theory, definitions of the evaluated functions, description of the setting of optimization and the discussion of the obtained results, including recommendations related to identified weaknesses of certain designs, are presented. The thesis also contains a description of an application that was created to display the results.

The dissertation thesis deal with the design and the optimization of the permanent magnet synchronous machine (SMPM) based on the artificial intelligence. The main target is to apply potential optimization methods on the design procedure of the machine and evaluate the effectiveness of optimization and the optimization usefulness. In general, the optimization of the material properties (NdFeB or SmCo), the efficiency maximization with given nominal input parameters, the cogging torque elimination are proposed. Moreover, the magnet shape optimization, shape of the air gap and the shape of slots were also performed. The well known Genetic algorithm and Self-Organizing migrating algorithm produced in Czech were presented and applied on the particular optimization issues. The basic principles (iterations) and definitions (penalty function and cost function) of proposed algorithms are demonstrated on the examples. The results of the vibration generator optimization (VG) with given power 7mW (0.1g acceleration) and the results of the SMPM 1,1kW (6 krpm) optimization are practically evaluated in the collaboration with industry. Proposed methods are useful for the optimization of PM machines and they are further theoretically applied on the low speed machine (10 krpm) optimization and high speed machine (120 krpm) optimization.

This thesis is focused on design and prototyping of solar panel position control system for an obtaining of the maxima renewable energy from sun. In this thesis, various ways of solar panel positioning are considered and analyzed. Consequently, a construction arrangement of the positioner is presented. It is mechanically adapted to obtain the maximum efficiency in typical environment corresponding with the Central European geographical latitude. Different methods of sun monitoring are considered and analyzed. On the basis of this analysis, a proper prototype of sun monitor for exact positioning with disturbance filtering has been constructed. Following part of work is devoted to stable, fully automated, control subsystem for reliable functionality of solar system. A suitable microprocessor with a robust firmware has been implemented to this control unit. Finally, system parameters measurement and closing analysis of gained renewable energy and backflow computation is presented in the end of this diploma thesis.

The aim of this master thesis is optimization of the rotor in the terms of efficiency. An analysis of the effects of rotor parameters is performed by RMXPRT. A genetic algorithm is created to find the optimal solution. Solutions are evaluated and adjusted according to the results. Measurements on the actual machine are performed and evaluated to verify the functionality of the simulation models.