The paper presents the study of an anti-lock braking system (ABS) that has been complemented by a fuzzy controller. The fuzzy controller was used to improve the braking performance of the vehicle, particularly in critical situations, for example, when braking a vehicle on wet road. The controller for the ABS was designed in the MATLAB/Simulink program. The designed controller was simulated on a medium-size vehicle model. During testing, three braking systems were simulated on the vehicle model. We compared the performance of a braking system without an ABS, a system with a threshold-based conventional ABS, and a braking system with the proposed ABS with a fuzzy controller. These three braking systems were simulation tested during braking the vehicle on a dry straight road and on a road with combined road adhesion. A maneuverability test was conducted, where the vehicle had to avoid an obstacle while braking. The results of each test are provided at the end of the paper.

In this paper the design and the magneto-static simulation of axial-flux permanent- magnet stepper motor with the disc type rotor is presented. Disk motors are particularly suitable for electrical vehicles, robots, valve control, pumps, centrifuges, fans, machine tools and manufacturing. The brushless machine with axial flux and permanent magnets, also called the disc-type machine, is an interesting alternative to its cylindrical radial flux counterpart due to the disk shape, compact construction and high torque density. This paper describes a design of four phase microstepping motor with the disc type rotor. The FEM modeling and the 3D magneto-static simulation of the disk stepper motor with permanent magnets is being subject of the article, too. Disc rotor type permanent magnet stepper motor for high torque to inertia ratio is ideal for robotics and CNC machines.

This article presents control methods for a three-phase BLDC motor using artificial intelligence. BLDC motor model and the control scheme used in simulation are presented in introductory part. Three control methods were compared in next part of the work, where we used a classic PI regulator compared with Fuzzy controller and neural network controller. Individual types of presented control methods were compared based on established parameters and results analysis of control methods, conclusions were drawn about the quality of individual methods of control.

Unlike the known isoelectronic undoped intrinsic FeAs compounds, LiFeAs does not show any spin-density wave behavior but exhibits superconductivity at ambient pressures without chemical doping. It has a superconducting transition temperature, T _c , of 18 K with electron-like carriers and a very high 0 K upper critical magnetic field, B _c2 (0), of greater than 80 T making the compound suitable for many high magnetic field applications at cryogenic temperatures. Oxypnictide materials are known for a complexity of their methods of preparation. The reported methods of LiFeAs preparation are based on the solid-state reaction at high temperatures (740 °-1050 °C) for long times (24-60 h). In the present work a simple electrochemical route is proposed for the preparation of a pnictide LiFeAs superconductor. During electrolysis, Li ions in the electrolyte become inserted into the FeAs lattice to form LiFeAs on the surface of the FeAs electrode. The proposed method differs from the existing electrochemical method and also from the traditional high temperature solid-state reaction methods. It is promising for the preparation of LiFeAs bulks and large scale LiFeAs films or tapes for various electric power or high magnetic field applications at cryogenic temperatures.

This paper presents a comparative analysis of distribution transformers with varying power ratings and insulation conditions using Frequency Domain Spectroscopy (FDS). The investigation was conducted both by comparing transformers with different performance ratings (from 100 to 1000 kVA) and insulation quality at a constant ambient temperature, and by evaluating insulation properties of a transformer across varying temperatures. The FDS method allows for separate assessments of oil quality and moisture content in solid insulation. An advantage of using capacitance measured by FDS for insulation assessment is its relatively lower sensitivity to temperature variations compared to the loss factor, a finding confirmed by temperature-effect analyses. However, assessing transformer insulation via capacitance measurements is influenced by the insulation’s geometric configuration, which depends on the transformer type and power rating. Therefore, when comparing the quality of insulating parts of transformers with different powers, it is recommended to compare the capacitance ratio depending on low frequencies against the capacitance at 50 Hz.

This paper deals with the design, implementation, and measurements of a frequency converter with bipolar sinusoidal pulse width modulation (SPWM) of output voltage for two-phase induction motors. The paper is dedicated to an analysis of the operation of a two-phase frequency converter and its implementation. The inverter has a single-phase H-bridge topology with split DC link and bipolar switching to minimise the number of components. Insulated gate bipolar transistors (IGBTs) are used in the realisation of the inverter power section. The inverter is controlled using a digital signal processor (DSP) TMS320F28335. Measurements with a 0.12 kW two-phase induction motor were performed to verify the correct operation of the inverter. The influence of the switching frequency on the motor current ripple is measured for frequencies of the first harmonic up to 100 Hz.