The bio-inspired algorithms are novel, modern, and efficient tools for the design of electrical machines. However, from the mathematical point of view, these problems belong to the most general ...branch of non-linear optimization problems, where these tools cannot guarantee that a global minimum is found. The numerical cost and the accuracy of these algorithms depend on the initialization of their internal parameters, which may themselves be the subject of parameter tuning according to the application. In practice, these optimization problems are even more challenging, because engineers are looking for robust designs, which are not sensitive to the tolerances and the manufacturing uncertainties. These criteria further increase these computationally expensive problems due to the additional evaluations of the goal function. The goal of this paper is to give an overview of the widely used optimization techniques in electrical machinery and to summarize the challenges and open problems in the applications of the robust design optimization and the prospects in the case of the newly emerging technologies.
Since large power transformers are custom-made, and their design process is a labor-intensive task, their design process is split into different parts. In tendering, the price calculation is based on ...the preliminary design of the transformer. Due to the complexity of this task, it belongs to the most general branch of discrete, non-linear mathematical optimization problems. Most of the published algorithms are using a copper filling factor based winding model to calculate the main dimensions of the transformer during this first, preliminary design step. Therefore, these cost optimization methods are not considering the detailed winding layout and the conductor dimensions. However, the knowledge of the exact conductor dimensions is essential to calculate the thermal behaviour of the windings and make a more accurate stray loss calculation. The paper presents a novel, evolutionary algorithm-based transformer optimization method which can determine the optimal conductor shape for the windings during this examined preliminary design stage. The accuracy of the presented FEM method was tested on an existing transformer design. Then the results of the proposed optimization method have been compared with a validated transformer design optimization algorithm.
Hysteresis loops constitute the source of important information for the designers of magnetic circuits in power transformers. The paper focused on the possibility to interpret the phenomenological ...T(x) model in terms of effective field vs. magnetization dependence. The interdependence of anhysteretic curve and hysteresis loops was emphasized. The concept of the anhysteretic plane introduced at the end of the last century by Sablik and Langman was subject to a tangible interpretation within the hyperbolic model framework. A novel geometric interpretation of the “effective field” related to the concept of affine transformation was introduced. It was shown in the paper that minor hysteresis loops of grain-oriented electrical steel may be described with the proposed formalism.
Contemporary beam-forming antenna arrays often use a large number of individual elements, sometimes hundreds or more, to achieve high gain for advanced applications like radar, space communication, ...and next-gen cellular networks. These arrays are complex and costly due to the need for precise amplitude and phase adjustments across the elements. The feeding network complexity leads to signal losses, reduced efficiency, and higher noise. Current research aims to simplify arrays, reduce active elements needing frontends, and streamline the feeding network, considering non-uniform, sparse, parasitic, or reflective arrays. Challenges arise from element coupling and imperfect models of high-frequency materials and electronic components. Therefore, in addition to simulations, practical experimentation remains vital. This paper focuses on designing a novel Formula Omitted element antenna array with digital quantized control. We explore the impact of quantized control on beamforming and plan to validate simplified orthogonal optimization methods with limited quantization depth. The proposed antenna array is applicable to 2400 MHz band research, including arrays with parasitic elements and switchable polarization for individual elements.
An alternative way of induction heating of nonmagnetic cylindrical billets is modeled. The billet rotates in static magnetic field generated by permanent magnets. The mathematical model of the ...process consisting of two second-order partial differential equations describing the distributions of magnetic and temperature fields is solved numerically in the quasi-coupled formulation. The computations are carried out by a fully adaptive higher order finite-element method that is implemented in own codes Agros2D and library Hermes. The most important results are verified experimentally on a prototype device built in our laboratory.
Parallel plate antennas (also known as improved TEM-cell or strip line antenna) are used in electromagnetic compatibility for radiated immunity and interference testing. Appropriately designed ...antenna represents a transmission line with TEM wave propagation and uniform electromagnetic field distribution between plates for specified frequency range. Device under test is positioned within the region of uniform EM field. In this study, we aimed to optimize electric properties of a small parallel plate antenna which was primarily designed for telecommunication devices testing. We hypothesized that initial design of the parallel plate antenna could be improved in terms of S-parameters by optimizing the impedance matching. Parametric optimization was based on numerical analysis using the finite element method; as an outcome, we achieved approx. 15 dB improvement of S11 parameter and verified the results by measurements. Thus, the optimized parallel plate antenna needs considerably less input power for the same field intensity within the specified frequency spectrum.
A technique for flexible control of induction baking of electrically non-conductive layers (paints, varnishes, resins, etc.) is presented, based on the temperature prediction. As the numerical ...solution of the full model of the process takes a long time, it is necessary to approximate it with a suitable equivalent model. In this case, recurrent neural networks (RNNs) prove to be a powerful tool for solving the task practically online and providing the input data to control the field current fast enough. The methodology was first tested to predict the current based on the knowledge of the voltage, which can be determined from the analytical solution of the ordinary differential equation that describes the feeding circuit. Subsequently, the methodology was implemented on a system for baking non-conductive layers.
Progress in implantable and ingestible wireless biotelemetry requires versatile and efficient antennas to communicate reliably from a body. We propose an ultraminiature 434 MHz antenna immune to ...impedance detuning caused by varying electromagnetic properties of the surrounding biological environment. It is designed for a standard input impedance of 50 Ω. The antenna is synthesized and miniaturized using a hybrid analytical-numerical approach, and then optimized to conform to the inner surface of a 17 mm long biocompatible encapsulation (7 mm diameter). The substrate is 50 μm thick. The capsule antenna is analyzed both in simplified and anatomically realistic heterogeneous phantoms. It remains matched at common implantation sites and through the whole gastrointestinal tract. Enhanced robustness allows using the antenna for a wide range of in-body applications. Computed reflection coefficients and radiation performance both show good agreement with measurements. The far field is characterized with the direct illumination technique using an analog fiber optic link. The realized gain (measured max. value -19.6 dBi) exceeds the counterparts by about 3 dBi. The proposed antenna contributes to the further development of a new generation of miniature in-body devices that involve complex and dense integration of sensors, logic, and power source.
A method of finding the temperature dependences of physical parameters of metals is proposed and discussed. The method is based on the combination of measurement of the surface temperature of the ...material and subsequent solution of the inverse problem using the multi-parametric optimization. Particular steps and algorithms are illustrated with an example.
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