Danjel Vončina

Dr. Danjel Vončina


Research Focus & Metrics

Academic Career Length

9Years (2018-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 December 2024 in Applied Sciences
Verified
Journal Article
Open access
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ARAndraz Rihar
Andraz Rihar
MNMitja Nemec
Mitja Nemec
HLHenrik Lavrič
Henrik Lavrič
PZPeter Zajec
Peter Zajec
DVDanjel Vončina
Danjel Vončina
KDKlemen Drobnic
Klemen Drobnic
The paper presents a comprehensive overview of recent advancements in power electronics and electric machine design, focusing on novel topologies, semiconductor technologies, and integrated design techniques for electric drives. New drive topologies are gradually moving from the research phase to practical application, aiming to increase the rated power, efficiency, and reliability of electric drives. Specifically, these topologies can be categorized into series, which focus on increasing the operating voltage; parallel, which aim at enhancing the operating current and adding redundancy; and multiphase, known for offering significant benefits such as improved fault tolerance, higher torque generation, the possibility of synthetic loading, and diverse winding layout options. Emerging wide bandgap semiconductors, such as silicon carbide and gallium nitride, allow for operation at higher frequencies and lower power losses, enabling further drive integration. In terms of design practices, higher computational power, supported by advanced software, enables simulation and analysis in multiple domains (thermal, mechanical, electromagnetic) using multiphysics co-simulation, as well as multi-objective optimization concepts to achieve rapid prototyping of optimized drive systems. All the approaches described are important steps towards further improving electric drives for numerous applications in industry, consumer electronics, and transportation.

13 April 2022 in Energies
Verified
Journal Article
Open access
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RMRoman Manko
Roman Manko
MVMario Vukotić
Mario Vukotić
DMDanilo Makuc
Danilo Makuc
DVDanjel Vončina
Danjel Vončina
DMDamijan Miljavec
Damijan Miljavec
SČSelma Čorović
Selma Čorović
An electrically excited synchronous machine (EESM) is a promising alternative to the permanent magnets synchronous machines being used in the automotive industry. However, the main disadvantage of the EESM with the conventional excitation system with brushes is the presence of slip rings on the shaft, which need regular maintenance. A promising alternative to the conventional excitation system of the EESM is a wireless power transfer (WPT) system. In this paper, we focused on WPT excitation system based on the rotary transformers. First, the model of the EESM in the d-q reference frame with vector control system has been built (based on the parameters of the real machine) and analyzed using MATLAB/Simulink software. Second, the influence of the rotary transformer design parameters on the dynamic performance of the EESM has been investigated. Finally, different topologies of the rotary transformers found in the literature have been analyzed, modeled and compared using an analytical and numerical approach. Based on the obtained results, the most suitable electrical parameters (i.e., geometry parameters, supply frequency, magnetizing and leakage inductance, winding resistance and efficiency) of the rotary transformer have been identified and implemented into the d-q model of EESM.

20 June 2023 in Energies
Verified
Journal Article
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RBRobert Baždarić
Robert Baždarić
Jasmin CelicJasmin Celic
Jasmin Celic
DVDanjel Vončina
Danjel Vončina
This paper presents a new approach to compensate for the current imbalance of an interleaved DC–DC buck converter (IBC), in which the current sensors are not involved in the operation of the converter when it is connected to an invariable load. The current sensors are only used during the offline identification process that builds the universal fuzzy model of the converter’s steady states. Model building involves an upstream identification phase, followed by further dimensionality reduction of the model and error minimization. The method presented here discusses the mathematical complexity of the analytical modelling of hybrid systems and opposes it with a complexity-reduced identification by learning from data. An offline rendered model of the stable and steady states of the IBC is used as a mapping of the required inverter output current to n-fold asymmetric duty cycles, which are distributed among the IBC phases to allow arbitrarily accurate load sharing. The mapping is carried out in the mathematically normalized space of variables or in the physical sense RMS values, achieving the desired robustness in a noisy environment and stability. The final and canonical feedback control is built from the standard and optimized PI controller, which is compensated by the identified IBC model correction. The only measured feedback of the whole controller is the output voltage. Even when applied to the simulation model (physical MATLAB platform) of a two-phase IBC with the built-in system asymmetry, the presented methodology is also applicable to the n-phase IBC without loss of generality.

26 November 2018 in Energies
Verified
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RBRobert Baždarić
Robert Baždarić
DVDanjel Vončina
Danjel Vončina
ISIgor Skrjanc
Igor Skrjanc
This paper introduces novel approaches to the predictive control of a DC-DC boost converter and a comparison of the controllers built that consider all of the current objectives and minimize the complexity of the online processing. The primary concern is given to the applicability of the inclined methods for systems that are physically small but considered physically fast processes. Although the performed methodologies are simulated and applied to a DC-DC boost converter, they can have broader applicability for different switched affine systems as a subgroup of the hybrid systems. The introduced methods present an alternative way of building the process model based on the fuzzy identification that contributes to the final objective: the applicability of the predictive methods for fast processes.

5 March 2026 in Results in Engineering
Verified
Journal Article
Open access
JGJurij Gostiša
Jurij Gostiša
MDMatevž Dular
Matevž Dular
ARAndraž Rihar
Andraž Rihar
BŠBrane Širok
Brane Širok
DVDanjel Vončina
Danjel Vončina
HLHenrik Lavrič
Henrik Lavrič

25 November 2025 in Applied Sciences
Verified
Journal Article
Open access
PDF file
MPMarko Petkovsek
Marko Petkovsek
PZPeter Zajec
Peter Zajec
MNMitja Nemec
Mitja Nemec
ARAndraz Rihar
Andraz Rihar
DVDanjel Vončina
Danjel Vončina
DNDavid Nedeljkovic
David Nedeljkovic
Despite the obvious shift in daily commuting towards electromobility, internal combustion engines (ICEs) still dominate the market, particularly in the transport sector. Their main drawback—cold-start emissions—has driven the development of active control strategies beyond passive exhaust optimizations. An electrically heated catalytic converter (EHC) helps the catalytic converter reach the light-off temperature more quickly through active control; however, it places additional demands on the already strained onboard electrical power distribution network. This paper presents a case study comparing two power supply and control configurations for managing the temperature of the EHC: (i) a smart-switch-based approach using bang-bang control, and (ii) a DC/DC converter with a proportional–integral–derivative (PID) controller. To define key target requirements for a dedicated DC/DC converter suitable for real-world conditions, measurement data such as temperature and electrical power demand were gathered through preliminary pollutant emissions tests performed in a laboratory environment using a programmable bench power supply. For the selected test procedure, engine cold-start emissions using various heater power supply scenarios were reduced by a factor of 6 for Total Hydrocarbons (THC) and by a factor of 5 for Carbon Monoxide (CO). Based on a comparative analysis of power supply parameters, a custom four-leg interleaved Buck converter was developed to meet the target power requirement and to specifically reduce voltage overstress caused by parasitic inductances in the onboard distribution network during rapid load current transients. The efficiency of the proposed DC/DC converter reached 95.8%. Unlike a bang-bang-controlled smart switch, the use of the DC/DC converter reduces both electrical and thermal stress on the vehicle’s cable harness.