This paper presents the current state of knowledge in the field of wireless power transfer. The concept of such a transfer and the basic methods of its implementation are described, together with block diagrams of the necessary devices. The technologies of electrical power transfer over short and long distances are characterized. The most popular electrical power transfer technology based on the phenomenon of electromagnetic induction is discussed in great detail. The analysis of the influences of such factors as the coupling factor, the shape of the coils, the type of ferromagnetic material from which the core of the coils is made, and the mutual position of the transmitting and receiving coils are analyzed on the properties of the wireless power transfer system. The advantages and disadvantages of the used technologies are shown. Furthermore, a wireless power transfer system is presented for charging the batteries of electric vehicles. The standards of wireless power transfer are also presented, and development trends are outlined.

The paper presents modern technologies of electrochemical energy storage. The classification of these technologies and detailed solutions for batteries, fuel cells, and supercapacitors are presented. For each of the considered electrochemical energy storage technologies, the structure and principle of operation are described, and the basic constructions are characterized. Values of the parameters characterizing individual technologies are compared and typical applications of each of them are indicated. Selected characteristics illustrating properties of the presented electrochemical energy storage devices are also shown. The advantages and disadvantages of the considered electrochemical energy storage devices and typical areas of their application are indicated. In addition, new, constantly developing technologies, not yet commercially available, are mentioned. Examples of existing energy storage solutions using the discussed technologies on the example of electric cars or storage systems in the world are given.

The paper presents a new average electrothermal model of the inductor dedicated to the computer analysis of dc-dc converters, such as a boost converter. The proposed model takes into account an influence of power losses in the ferromagnetic core on frequency and temperature. The considered model includes parameters, values of which are estimated on the basis of the catalogue data of the inductor components - the core and the winding. To prove the usefulness of the average electrothermal model of the inductor, calculations of the characteristics of the boost converter were performed. The results of calculations were compared with the results of measurements and the good agreement between these results was achieved for two types of ferromagnetic cores made of powdered iron (RTP) or ferrite (RTF).

This paper presents the method of modeling single-inductor dc-dc converters with thermal phenomena in the inductor taken into account. The electrothermal models of an inductor and semiconductor devices in the form dedicated for SPICE are proposed. Using the proposed models, the electrothermal analysis of buck and boost converters was performed for the inductor with cores made of different ferromagnetic materials. It was proved that nonlinearity of the inductor characteristics and thermal phenomena occurring in this element should be taken into account when the converter operates at high frequency range (over 200 kHz), especially for the inductor with the powder core.

This paper presents a compact nonlinear thermal model of pulse transformers. The proposed model takes into account differentiation in values of the temperatures of a ferromagnetic core and each winding. The model is formulated in the form of an electric network realising electrothermal analogy. It consists of current sources representing power dissipated in the core and in each of the windings, capacitors representing thermal capacitances and controlled current sources modelling the influence of dissipated power on the thermal resistances in the proposed model. Both self-heating phenomena in each component of the transformer and mutual thermal couplings between each pair of these components are taken into account. A description of the elaborated model is presented, and the process to estimate the model parameters is proposed. The proposed model was verified experimentally for different transformers. Good agreement between the calculated and measured waveforms of each component temperature of the tested pulse transformers was obtained. Differences between the results of measurements and calculations did not exceed 9% for transformers with a toroidal core and 13% for planar transformers.