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.

In this paper, the problem of how to describe the thermal properties of the insulated-gate bipolar transistor (IGBT) module with the use of the compact thermal model is considered. This model makes it possible to calculate internal temperature of every semiconductor device included in this module with self-heating phenomena and mutual thermal couplings between these devices taken into account. A new method of measuring parameters of the thermal model of devices contained in the considered module is proposed, and the accuracy of this method is discussed. Some results of measurements of the considered parameters are presented, and uneven distribution of temperature in the investigated module in selected conditions of its power supply is evaluated. Differences between the measured waveforms of the internal temperature of components of the IGBT module and its casings are discussed.

In this paper, the isothermal model of power MOS transistors offered by the producer of these devices and the electrothermal model of these devices proposed by the authors are presented. The results of experimental verification of both the models are given as well.

The one-dimension frequency analysis based on DFT (Discrete FT) is sufficient in many cases in detecting power disturbances and evaluating power quality (PQ). To illustrate in a more comprehensive manner the character of the signal, time-frequency analyses are performed. The most common known time-frequency representations (TFR) are spectrogram (SPEC) and Gabor Transform (GT). However, the method has a relatively low time-frequency resolution. The other TFR: Discreet Dyadic Wavelet Transform (DDWT), Smoothed Pseudo Wigner-Ville Distribution (SPWVD) and new Gabor-Wigner Transform (GWT) are described in the paper. The main features of the transforms, on the basis of testing signals, are presented.

In this paper the problem of modelling thermal properties of the IGBT using a non-linear compact thermal model is considered. This model has the form of an electrical network. In the proposed model influence of internal temperature of this transistor on efficiency of heat dissipation is taken into account. The elaborated model form is presented and the estimation method of this model parameters is described. Correctness of the new model is verified experimentally for different cooling conditions and different values of ambient temperature. Additionally, some results of calculations are compared to the results of calculations performed using selected models given in literature.