1. Integrating Multi-Physics Modeling within Multi-Objective Optimization to Enhance the Performance and Efficiency of Permanent Magnet Synchronous Machines : doktorska disertacijaMitja Garmut, 2025, doctoral dissertation Abstract: This Dissertation focuses on the optimization of an Interior Permanent Magnet (IPM) machine for handheld battery-powered tools, aiming to enhance performance and efficiency.
The research integrates multi-physics modeling, including electromagnetic Finite Element Method (FEM) and thermal models, to evaluate machine performance under various operating conditions. The performance is evaluated according to selected Key Performance Indicators (KPIs). Further, different control methods, such as Field Oriented Control and Square-Wave Control, impact the performance significantly and are incorporated into the optimization process.
Due to the computational challenges of FEM-based performance evaluations in Multi-Objective Optimization (MOO), this work utilizes Artificial Neural Network (ANN)-based meta-models, to accelerate the optimization process while preserving accuracy.
The developed meta-models capture nonlinear machine characteristics from the FEM model. These meta-models are then used to evaluate machine performance through a combination of analytical and numerical post-processing methods.
Four MOO scenarios are presented, each aimed at optimizing the cross-sectional design of IPM machines, to enhance performance and efficiency while reducing mass and cost. Additionally, these scenarios modify the machine’s electromagnetic behavior, to ensure better alignment with the selected control method.
By comparing the optimization process of Scenario 1, which uses direct FEM-based evaluation without time reduction measures, to the approach incorporating Artificial Neural Network based meta-models, the total number of individual FEM evaluations decreased from 2.35×10^9 to 2.03×10^5, without almost any loss of accuracy. This reduced the computation time from 297 years to 9.07 days on our standard desktop computer. The obtained ANN-base meta-models can be used further for other optimizations without the need for additional FEM evaluations.
In all four optimization scenarios, the use of meta-models enabled the generation of a Pareto front of the optimal solutions, leading to improved KPIs compared to the reference design. The highest relative improvement occurred in Scenario 1, where the selected optimized machine design achieved a 30% increase in power density compared to the reference design.
Keywords: Interior Permanent Magnet (IPM) Machine, Artificial Neural Network (ANN), Meta-Modeling, Multi-Objective Optimization (MOO), Finite Element Method (FEM), Multi-Physics Modeling, Field Oriented Control (FOC), Square-Wave Control (SWC)
Published in DKUM: 15.05.2025; Views: 0; Downloads: 12
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2. Toward embedded system resources relaxation based on the event-triggered feedback control approachAndrej Sarjaš, Dušan Gleich, 2022, original scientific article Abstract: The paper describes an event-triggered nonlinear feedback controller design. Event triggering is a real-time controller implementation technique which reduces embedded system utilization
and relaxes task scheduling of the real-time system. In contrast to classic time implementation
techniques, the event-triggered execution is validated regarding the introduced triggering policy.
The triggering rule is a boundary, where the last task value is preserved until the rule is violated.
In the given paper, two different event-triggered strategies are designed for the class of dynamic
systems with integral behavior. Both methods are based on sliding mode controller design, where the
triggering rule of the first design involves only a partial state vector, which is a direct consequence of
the triggering rule derivation throughout the Lyapunov stability analysis. In the second approach,
the sliding mode controller is designed upon prior stabilized systems with the additional term, which
enables derivation of the triggering rule based on the whole state vector. The second approach offers
better closed-loop performance and higher relaxation of the system utilization. The selection of
triggering boundary is related closely to the derived minimal inter-event time, which impacts the
computational burden of the real-time system and closed-loop performance directly. The derived
controllers are compared with the classic sample and hold implementation techniques. The real-time
results are presented, and system performances are confirmed regarding embedded system task
relaxation, lowering the computational intensity and preserving closed-loop dynamics.
Keywords: sliding mode control, event-triggered control, lowering computational intensity, task relaxation
Published in DKUM: 28.03.2025; Views: 0; Downloads: 7
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3. Control of an inductive power transfer system using a double coil structureNataša Prosen, Mitja Truntič, Jure Domajnko, 2022, original scientific article Abstract: This paper presents the design of the control of the system using a double DD coil structure.
The double DD coil is a layered coil structure that consists of two single DD coils, rotated to each other
by 90◦. A large-signal and small-signal model of the proposed IPT system are designed for control
synthesis. The small-signal model is derived from the large-signal using harmonic approximation
and the extended describing functions (EDF). For the small-signal model, voltage and current control
schemes were proposed for the purpose of wireless battery charging. The robustness of the control is
tested on a small-scale IPT system using double DD coils and resistive load. The results are evaluated
at different reference voltages, currents, loads and coupling coefficients.
Keywords: wireless power transfer, double DD coil structure, voltage control, IPT with multiple coils
Published in DKUM: 28.03.2025; Views: 0; Downloads: 2
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4. Control of a modified switched-capacitor boost converterBenjamin Ošlaj, Mitja Truntič, 2022, original scientific article Abstract: Switched-capacitor converters and their alternatives have been shown to provide high
efficiency with high power densities on smaller volumes, and can thereby be a suitable choice for
energy harvesting. This paper proposes a hybrid power architecture based on a switched-capacitor
topology and a boost converter that can be used for such purposes. A switching capacitor circuit
can achieve any voltage ratio, allowing a boost converter to increase the input voltage to higher
voltage levels. The first stage is unregulated with high-efficiency voltage conversion. The boost stage
provides a regulated voltage output on such a converter. Rather than cascading two converters, their
operation is integrated for the output voltage regulation. One major problem of switched-capacitor
converters is output voltage regulation, which is solved by the interconnection of the power stages.
The simplicity and robustness of the solution provide the possibility to achieve higher voltage ratios
than cascading boost converters and provide higher efficiency. The converter’s size and cost can be
improved with the integration of switching capacitors in DC-DC converter structures. A converter
prototype has been designed, modelled, and built for the input voltage level of 2 V and power level
of 5 W.
Keywords: SC-BC, cascade control, low power, low voltage
Published in DKUM: 28.03.2025; Views: 0; Downloads: 2
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5. Evolution of domain-specific modeling language: an example of an industrial case study on an RT-sequencerTomaž Kos, Marjan Mernik, Tomaž Kosar, 2022, original scientific article Abstract: Model-driven engineering is a well-established software development methodology that
uses models to develop applications where the end-users with visual elements model abstractions
from a specific domain. These models are based on domain-specific modeling language (DSML),
which is particular to the problem domain. During DSML use, new ideas emerge and DSMLs evolve.
However, reports on DSML evolution are rare. This study presents a new DSML called RT-Sequencer
that evolved from our DSML Sequencer to support, in addition to the Data Acquisition domain,
also a new domain—Real-Time Control (RTC) systems. The process of defining models with a new
language RT-Sequencer has changed in a way that new end-users were introduced—advanced endusers, which use general-purpose language (GPL) and advanced programming concepts to define
modeling environments for the RT-Sequencer end-users. More specifically, an industrial experience
with the RT-Sequencer is presented, where DSML was opened for extension so that a GPL code
could be inserted into the model to create new visual blocks for the end-user, and the possibility to
adapt and optimize the execution code for a particular task. Our experience shows the specific case
of DSML evolution supporting another problem domain, and the implementation effort needed to
extend domain-specific modeling language with GPL support.
Keywords: model-driven engineering, domain-specific modeling languages, measurement systems, Real-Time Control systems, data acquisition, language evolution, experience report
Published in DKUM: 27.03.2025; Views: 0; Downloads: 2
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6. Is the Hitchcock story really true? Public opinion on Hooded crows in cities as input to managementLászló Kövér, Petra Paládi, Isma Benmazouz, Andrej Šorgo, Natalija Špur, Lajos Juhász, Peter Czine, Péter Balogh, Szabolcs Lengyel, 2022, original scientific article Abstract: In recent years, the Hooded crow (Corvus cornix) has become one of the most successful wild bird species in urban environments across Europe. Hooded crows can cause several problems in cities, including trash scattering, noise disturbance, and aggressive behavior toward humans or pets, and they can be potential vectors of pathogens. To find effective solutions, the public has to be involved in the decision-making process in urban planning management, managed by the city administration. In this study, we surveyed the attitude of people in Hungary towards crows and crow management by collecting information using an online questionnaire containing 65 questions published in 14 Facebook groups. We found that many people were familiar with corvid species and had personal experience with them. In most cases, these experiences were not negative, so the crows were not or only rarely perceived to cause problems to people, such as aggressive behavior, damage to cars or stealing something. Most respondents recognized that the presence of large numbers of hooded crows is a problem to be solved and acknowledged that they do not know how to resolve it. The majority of people expressed their interest in raising public awareness of crows but not in their management actions, which they believe should be implemented by experts. Most respondents preferred passive, harmless methods. More direct methods such as egg/chick removal from the nest, control by trapping, poisoned baits or firearms, or oral contraceptives were the least acceptable. These results express the difficulty in identifying a control method for managing hooded crow populations that is both acceptable to most people and effective at the same time. This study demonstrates the importance of involving public opinion in wildlife management and providing more information to citizens to reduce human-crow conflicts.
Keywords: attitude, control, corvids, human-wildlife conflict, urban wildlife management
Published in DKUM: 27.03.2025; Views: 0; Downloads: 2
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7. Sensitivity analysis of MTPA control to angle errors for synchronous reluctance machinesMartin Petrun, Jernej Černelič, 2025, original scientific article Abstract: This study investigated the sensitivity of maximum torque per ampere (MTPA) control in synchronous reluctance machines (SynRMs) to angle errors, examining specifically how deviations in the reference control trajectory affected performance. Analytical and numerical methods were employed to analyze this sensitivity systematically, including the impact of magnetic saturation. Two MTPA control implementation schemes were evaluated, with torque and current amplitude as the reference variables, using a template SynRM from the open-source simulation tool SyR-e. The results indicated that performance sensitivity to angle errors was moderately low near the MTPA trajectory, allowing for significant angle deviations with minimal performance loss. Although magnetic saturation increased this sensitivity slightly, reducing the allowable error range by up to 25%, the maximum angle deviation for up to 1% of the performance decrease still corresponded to approximately ±3∘ around the MTPA trajectory. The findings of this study suggest potential for simplifying control implementations, reducing component costs through less precise position determination (sensor-based or sensorless), and achieving additional control objectives such as torque ripple reduction.
Keywords: control angle error, finite element method, MTPA control, sensitivity to performance decrease, suboptimal operation, synchronous reluctance machines
Published in DKUM: 07.02.2025; Views: 0; Downloads: 6
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8. Control of sliding entrance door with radio frequency identification : master's thesisMatija Pribanić, 2024, master's thesis Abstract: This master's thesis addresses the issue of surveillance and the right of access to protected zones. NFC technology was selected as a solution for identifying and monitoring sliding doors. The monitoring system is connected to the web server via an Internet connection, which enables easier data processing and more straightforward data access. In this master's thesis, a scaled sliding door model was used that was made using a 3D printer. The thesis also addresses the issue of powering the system using an uninterruptible power supply (UPS) system in the event of a power outage. The monitoring and control system is designated and implemented as a modular system consisting of a UPS, NFC, and the main module. The UPS module powers the system and ensures an uninterrupted power supply. The NFC module is used to communicate between the user of the NFC key and the system. The main module is intended for processing the data received from other modules and components in the security system, managing the sliding doors, and sending the processed data to the controller.
Keywords: access control system, near-field communication, ISO/IEC 14443 standard, radio frequency identification, sliding door
Published in DKUM: 06.02.2025; Views: 0; Downloads: 8
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9. Modeling and control of a three-phase interleaved buck converter as a battery chargerEl Nouha Mammeri, Oswaldo Lopez-Santos, Abdelali El Aroudi, Jure Domajnko, Nataša Prosen, Luis Martinez-Salamero, 2025, original scientific article Abstract: In this paper, a control design methodology is proposed for the implementation of a three-phase interleaved buck converter as a battery charger. The control strategy consists of a multiple-loop controller in cascade configuration to implement the constant-current constant-voltage (CC-CV) protocol for the fast charging of an electric vehicle (EV) battery. To compensate for the inherent asymmetric distribution of the current between the phases, the first control loop (inner loop) is dedicated to implement the democratic current sharing technique, while the two outer loops constitute a seamless controller, which allows a soft transition from CC mode to CV mode when charging the battery. The controllers are designed using the root locus method and conventional rules for cascade controllers. The design methodology is validated and tested by numerical simulations of the switched model system implemented in PSIM software. The obtained results put in evidence a robust performance in front of input voltage and load variations, failure conditions and other parametric uncertainties. A 1.5 kW experimental prototype is implemented to charge a battery of 48 V from a 100 V DC input voltage and to validate the theoretical predictions and the simulation results. The proposal opens the way for subsequent research in ultrafast charging of batteries.
Keywords: battery charger, interleaved buck converter, cascade control, fast charging
Published in DKUM: 30.01.2025; Views: 0; Downloads: 4
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10. Presaditev trebušne slinavke : indikacija, kirurška tehnika, klinični pomenGaja Hladnik, Vojko Flis, 2024, review article Abstract: Presaditev trebušne slinavke je zlati standard za zdravljenje ledvične odpovedi pri bolnikih s sladkorno
boleznijo oz. pri bolnikih s sladkorno boleznijo, kjer kljub intenzivirani inzulinski terapiji ne uspemo preprečiti
nastanka kroničnih zapletov sladkorne bolezni. Z napredkom kirurgije in novimi imunosupresivnimi zdravili je v zadnjih desetletjih prišlo do bistvenega izboljšanja preživetja bolnikov in presadkov ter povečane kakovosti življenja po presaditvi. Presaditev trebušne slinavke je danes metoda izbire, s katero nadomestimo endokrino funkcijo trebušne slinavke, vzpostavimo normoglikemijo in preprečimo nastanek sekundarnih zapletov sladkorne bolezni. Med presaditve trebušne slinavke prištevamo sočasno presaditev trebušne slinavke in ledvice, presaditev
samo trebušne slinavke, presaditev dela trebušne slinavke ter presaditev otočkovtrebušne slinavke. Enoletno preživetje bolnikov po presaditvi trebušne slinavke znaša 96 %, petletno pa 80 %. Preživetje je najbolj optimalno pri sočasni presaditvi trebušne slinavke in ledvice.
Keywords: pancreas transplantation, diabetes mellitus, glycemic control, simultaneous pancreas-kidney transplantation
Published in DKUM: 28.01.2025; Views: 0; Downloads: 22
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