Irena Kováčová

Introduction. Multi-branch buck-boost converters, widely used in energy conversion from alternative sources, offer significant advantages over single-branch configurations. Critical, however, is the question of the appropriate number of branches for optimal efficiency and the given output power of the converter. The novelty of the proposed work consists in the development of a precise method for determining the optimal number of branches in a multi-branch buck-boost converter for a specified output power. Additionally, the findings enable the development of adaptive control strategies that dynamically adjust the number of active branches based on the converter’s instantaneous power. This approach enhances the overall efficiency of the converter. Goal. The study aims to analyze the efficiency of multi-branch buck-boost converters, focusing on the optimal number of branches and the required output power. Methods. The problem was addressed through a theoretical analysis of the converter’s electrical equivalent circuit. The theoretical results were validated through practical measurements conducted on a prototype converter. Results. A detailed equivalent circuit for the converter was developed and analyzed for various operational modes. Based on this analysis, the converter’s losses were quantified, and a relationship was derived to determine the optimal number of parallel branches, taking into account the desired output power. Practical value. The findings provide guidelines for selecting the optimal number of branches in a multi-branch buck-boost converter based on the desired output power. Furthermore, they enable the implementation of adaptive switching strategies to maximize the converter’s efficiency. References 22, table 2, figures 20.

This article presents the enhancement and refinement of a simulation model for an integrated universal switched voltage regulator compatible with PSPICE software. The model enables users to create representations of any specific type of switch...

As the global emphasis on solar energy intensifies, optimizing the efficiency of photovoltaic panels becomes crucial in meeting energy demands sustainably. Addressing this, our research delves deeply into advancing maximum power point tracking (MPPT), a pivotal component in perfecting the energy conversion process. Leveraging state-of-the-art mathematical modeling, in-depth simulations, and comprehensive experimental validation, we set out to markedly refine the performance of non-isolated multi-branch buck DC–DC converters. In this pursuit, we introduce an innovative algorithm meticulously designed to adjust the number of active branches. This adjustment is rooted in robust efficiency metrics, ensuring optimal power delivery even under dynamic and fluctuating conditions. We place a distinct emphasis on the transformative role of current in determining converter efficiency. Drawing from our findings, we advocate for an adaptive control strategy, precisely engineered to thrive in a spectrum of operational contexts. With this study, we not only present pivotal contributions to the domain of photovoltaic technology but also chart out clear expectations for future endeavors. Our hope is that these advancements serve as foundational steps, guiding the evolution of sustainable energy generation.

The paper deals with a brief overview of magnetoelastic sensors and magnetoelastic sensors used in general for sensing bending forces, either directly or sensing bent structures, and defines the current state of the art. Bulk magnetoelastic force sensors are usually manufactured from transformer sheets or amorphous alloys. In praxis, usually, a compressive force is sensed by bulk magnetoelastic sensors; however, in this paper, the sensor is used for the measurement of bending forces, one reason being that the effect of such forces is easily experimentally tested, whereas compressive forces acting on a single sheet make buckling prevention a challenge. The measurement of the material characteristics that served as inputs into a FEM simulation model of the sensor is presented and described. The used material was considered to be mechanically and magnetically isotropic and magnetically nonlinear, even though the real sheet showed anisotropic behavior to some degree. A sinusoidal magnetizing current waveform was used in the experimental part of this paper, which was created by a current source. The effects of various frequencies, amplitudes, and sensor geometries were tested. The experimental part of this paper studies the sensors’ RMS voltage changes to different loadings that bend the sheet out of its plane. The output voltage was the induced voltage in the secondary coil and was further analyzed to compute the linearity and sensitivity of the sensor at the specific current characteristic. It was found that for the given material, the most favorable operating conditions are obtained with higher frequency signals and higher excitation current amplitudes. The linearity of the sensor can be improved by placing the holes of the windings at different angles than 90° and by placing them further apart along the sheet’s length. The current source was created by a simple op-amp voltage-to-current source controlled by a signal generator, which created a stable waveform. It was found that transformer sheet bending sensors with the dimensions described in this paper are suitable for the measurement of small forces in the range of up to 2 N for the shorter sensors and approximately 0.2 N for the longer sensors.

The article deals with the issue of determining the magnitude of disruptive voltage in the analyzed circuit, which is generated by the power device circuit, based on the electrical and geometric parameters of these circuits and simulation. The magnitude of this voltage can cause disturbances and errors in the device, which have become more significant due to the increasing complexity of electronic circuits. Therefore, according to technical legislation, it is necessary to strictly adhere to the concept of electromagnetic compatibility (EMC) for all products. This way of investigating EMC is the most cost-effective. The investigation focuses on four fundamental paths of energy transfer: galvanic, inductive, capacitive, and electromagnetic.

The article describes the design of a universal simulation model of a voltage regulator for applications compatible with the globally used PSpice program. Users can create a model of any type of integrated switching voltage regulator that is currently available on the market by setting its individual parameters. The proposed connection of the regulator was applied in the connection of the buck DC–DC converter. The accuracy of the model was verified by comparing the results obtained by the simulation to other official models and to practical measurements taken on a real sample of the converter. The versatility of the model was proven by comparison with another type of converter with different parameters.

The article describes the implementation of IoT technology in the teaching of microprocessor technology. The method presented in the article combines the reality and virtualization of the microprocessor technology laboratory. A created IoT monitoring device monitors the students’ microcontroller pins and sends the data to the server to which the teacher is connected via the control application. The teacher has the opportunity to monitor the development of tasks and student code of the program, where the functionality of these tasks can be verified. Thanks to the IoT remote laboratory implementation, students’ tasks during the lesson were improved. As many as 53% (n = 8) of those students who could improve their results achieved an improvement of one or up to two tasks during class. Before the IoT remote laboratory application, up to 30% (n = 6) of students could not solve any task and only 25% (n = 5) solved two tasks (full number of tasks) during the class. Before implementation, 45% (n = 9) solved one problem. After applying the IoT remote laboratory, these numbers increased significantly and up to 50% (n = 10) of students solved the full number of tasks. In contrast, only 10% (n = 2) of students did not solve any task.

The article describes the principles based on which it is possible to obtain energy from renewable sources more efficiently. The principles use the conventional DC-DC interleaved buck converter based on the common electronic component types and the control strategy. A novelty of such a proposed solution lies in the methods which are not new, but with the right combination, better results can be achieved. The resulting method can be implemented into various topologies where the highest efficiency for wide input power is required. In case of the renewable energy sources where the power can vary hugely during the day, the proposed method can be implemented. Therefore, the article provides several steps, from calculation through simulation to experimental results that brings reader close to understanding of a such proposed solution.

The paper presents analyses of the implementation of IoT in the patent technology of the remote measuring laboratory (VMLab). The technology allows to create a new electrical connection between different devices, where the connection diagram was not defined before. This may be done remotely around the world. To begin with, an application of this technology as a remote measuring laboratory is presented and described. Analyses of the possible application of IoT technology in the Remote Measurement Laboratory (VMLAB) with a final design are also presented. The research focuses on an efficient way to retrieve measured values synchronized over the Internet from multiple measuring devices and controllable devices, without an Ethernet or Wi-Fi interface from the manufacturer. The analyses may also be useful when implementing an additional IoT approach to existing systems.