A novel diagnosis method based on the rotor slip is proposed in the paper to correctly detect current and speed sensor failures during the induction motor drive (IMD) operation. In order to enhance reliability and avoid confusion in the diagnosis algorithm due to the influence of measured signal quality, each fault type is determined in a priority order defined by the diagnosis method. Based on the features of the IMD applying the field-oriented control (FOC) technique, an innovative model uses the measured currents and reference speed as the input signals to estimate the rotor slip for the current sensor fault detection. After verifying the quality of the feedback of the current signals, a speed sensor fault function is continued, and performs according to relations among the reference speed, estimated speed based on the sliding mode method, and measured rotor speeds. Finally, the estimated quantities are selected to replace the wrong measured current or speed signals. The feasibility of the proposed approach is verified by simulations using Matlab-Simulink software as well as by practical experiments using an IMD prototype with a rated power of 2.2 kW and a DSC-TMS320F28335-based control system. The obtained simulation and experimental results demonstrated the feasibility, effectiveness, and reliability of the proposed diagnosis technique in detecting sensor failures and maintaining the stable operation of the IMD.

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.

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.

Linearization is a powerful tool that enables the analysis and control of nonlinear systems by simplifying their dynamics and allowing the use of well-established linear control techniques. This paper presents a new methodology for the linearization of dynamic nonlinear systems that can be applied without the need to know their internal structure and parameters solely from measured input/output data. The proposed technique, based on fuzzy logic, simplifies a higher-order nonlinear system into a first-order nonlinear fuzzy system. This enables the design of control systems based on an inverse fuzzy model in the vicinity of the chosen operating point. The properties of the proposed methodology were first verified for less complex systems by simulation in MATLAB. This paper presents the application of this method for torque control of an induction motor, which is a complex nonlinear system of the fifth order. The results were experimentally validated by measurements using an IC inverter–induction motor system. The experimental measurements confirmed the correctness and quality of the proposed methodology. Compared to traditional methods, it does not require any knowledge of the mathematical model of the nonlinear system, use of complex differential algebra, or other additional transformations. The proposed non-analytical linearization technique is primarily designed for a class of mechatronic systems with electric drives. Its simple structure and design methodology minimize the complexity of implementation, thereby enabling it to be widely used in industrial practice for other nonlinear systems with comparable structures.

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.

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.