Tibor Vajsz

57193135469

Publications - 5

A Novel Motor Modelling Method for Reluctance Motor Electric Vehicle Drive Systems

István Szászi Tibor Vajsz Csongor Horváth Richárd Csaba Kovács Vilmos Paiss István Szászi

Publication Name: Proceedings 2025 IEEE 7th Global Power Energy and Communication Conference Gpecom 2025

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: 216-221

Description:

The field of electric vehicles is one of the most popular research topics today. These vehicles require highly efficient and cost-competitive drive system solutions due to the increasing competition. The reluctance motor drive systems are excellent candidates for fulfilling these requirements However, the controlling of these drive systems is difficult as they represent a heavily nonlinear behavior due to the varying stator inductances. The stator inductances are changing both in the function of the stator currents- and that of the rotor position. This phenomenon makes it necessary to apply advanced modelling solutions that provide a more precise motor model for the torque control algorithm. This paper presents a novel motor modeling method for the reluctance motor drive systems. A new type of inductance matrix is derived, which is a critical part of the motor model. This inductance matrix is used to define new relationships for the electromagnetic torque and the phase voltages of the machine for a given stator current, leading to a novel motor model. This new motor model can serve as an input for the torque control algorithm research and development activities.

Open Access: Yes

DOI: 10.1109/GPECOM65896.2025.11062014

A New Type of Motor Topology for Reducing the Torque Ripples in Synchronous Reluctance Motor Drives of Electric Vehicles

István Szászi Tibor Vajsz Csongor Horváth Richárd Csaba Kovács Vilmos Paiss István Szászi

Publication Name: Lecture Notes in Networks and Systems

Publication Date: 2025-01-01

Volume: 1258 LNNS

Issue: Unknown

Page Range: 528-540

Description:

Electric vehicle applications are one of the most popular topics in the case of electric motor research & development activities. Novel types of electric motor solutions, offering new advantages are gaining significant attention today. Synchronous reluctance motors (SynRMs) have several advantages that are particularly useful in the case of electric vehicle applications. Their lower costs, their robust buildup and their excellent efficiency are all features that are greatly desired in the case of electric mobility applications. However, SynRMs are well known in the literature for producing more torque ripples with the conventional torque control methods. One way to reduce the torque ripples is to use advanced torque control algorithms. The other way is to use optimized motor topologies with the conventional torque control algorithms. The paper aims at the investigation of the motor design concepts that could be applied for reducing the torque ripples of a SynRM drive. It will be analyzed whether the typical relationships and concepts that are used for minimizing the torque ripples in the case of a PMSM can also be applied for a SynRM or not. Simulations will be carried out in JMAG environment to validate the new concepts. The reduced amount of the torque ripples leads to a less amount of audible noise, which can be an advantage in the case of certain electric vehicle applications and for certain customers.

Open Access: Yes

DOI: 10.1007/978-3-031-81799-1_48

A Novel Coenergy Based Torque Calculation Method for the Reluctance Motor Drives of Electric Vehicles

István Szászi Tibor Vajsz Csongor Horváth Richárd Csaba Kovács Vilmos Paiss István Szászi

Publication Name: Proceedings 2025 IEEE 7th Global Power Energy and Communication Conference Gpecom 2025

Publication Date: 2025-01-01

Volume: Unknown

Issue: Unknown

Page Range: 210-215

Description:

Nowadays, the field of electric mobility is experiencing a rapid evolution. The need for more competitive electric vehicles is affecting the field of electric motor drive systems as well, placing the alternative types of electric motors into the center of research attention. The reluctance motors are one of these alternative motor types, but their highly nonlinear characteristics place a significant burden to their application. The stator inductances are varying in the function of the stator currents, and also in the function of the rotor position due to the magnetically asymmetric rotor structure. This means that the traditional calculation methods for the electromagnetic torque of the machine yield in inaccurate results. Therefore, this paper presents a novel, generalized coenergy-based torque calculation method, which eliminates a significant constraint of the traditional magnetic energy- and coenergy-based torque calculation methods, and considers the highly nonlinear behavior of the machine as well.

Open Access: Yes

DOI: 10.1109/GPECOM65896.2025.11061976

Comprehensive Analysis of Radial- and Axial Flux Synchronous Reluctance Machines for Electric Vehicle Applications

Tibor Vajsz Csongor Horváth Richárd Csaba Kovács Vilmos Paiss Dániel Norbert Szántó István Szászi

Publication Name: Lecture Notes in Networks and Systems

Publication Date: 2026-01-01

Volume: 1768 LNNS

Issue: Unknown

Page Range: 399-420

Description:

Synchronous Reluctance Machines (SRMs) have been gaining considerable research interest recently because of the absence of the permanent magnets (no rare-earth materials), their robust construction and high partial load efficiency. Their inherently lower torque density compared to permanent magnet synchronous machines remains a challenge. However, adopting an axial flux topology could potentially improve this feature. This paper analyzes the properties of the axial flux configuration and compares them with those of the traditional radial flux topology for synchronous reluctance machines used in electric vehicles. The paper focuses on the differences in the torque-production, in the efficiency, in the torque densities and in the weight and the physical dimensions. Additionally, this paper examines the material costs for the two machine types and investigates their predicted future prices to determine the more cost-effective solution for electric vehicle applications. Simulation investigations will be carried out to examine these properties. It will be shown that the axial flux topology is an attractive alternative to the nowadays widely used radial flux one in the case of synchronous reluctance machines of electric vehicles.

Open Access: Yes

DOI: 10.1007/978-3-032-13898-9_45

An Investigation of Axial Flux Synchronous Reluctance Machines with Aluminum- and Copper Windings for Electric Vehicle Applications

Tibor Vajsz Csongor Horváth Richárd Csaba Kovács Vilmos Paiss Dániel Norbert Szántó István Szászi

Publication Name: Lecture Notes in Networks and Systems

Publication Date: 2026-01-01

Volume: 1768 LNNS

Issue: Unknown

Page Range: 428-442

Description:

Synchronous reluctance machines offer a cost-effective alternative to the nowadays widely used permanent magnet synchronous machines in applications that require high partial-load efficiency. Pumps, fans, compressors and electric vehicle drive systems are all good examples for such applications. Synchronous reluctance machines do not need any permanent magnets for the torque-production, which means that they are not affected by the drawbacks related to them. The nowadays most widely used permanent magnets are based on rare-earth minerals, which present significant supply chain issues, burdened by severe geopolitical tensions. These difficulties can all be eliminated by using synchronous reluctance machines, while offering high partial-load efficiency. The utilization of the axial flux topology enhances the torque density, further increasing the attractiveness of these machines. However, it is important to analyze the other possibilities to improve the characteristics of the machine to make them even more appealing in the case of electric vehicle applications. Such an option is to apply an aluminum winding instead of a copper-based one. This paper presents an investigation for the application of the aluminum winding to improve the most important characteristics of the Axial Flux Synchronous Reluctance Machines (AFSRMs). Simulation examinations will be carried out to analyze the potential possibilities to enhance the characteristics of the machine. It will be shown that the aluminum winding requires an alternative design to achieve improvements over the copper-based one in the most relevant attributes. Also, it will be shown that with the appropriate design the aluminum-winding-based AFSRM is able to outperform the copper-winding-based one, offering a significant cost-advantage with only a minor compromise in the geometrical dimensions of the machine, which is an acceptable compromise in the case of an electric vehicle application.

Open Access: Yes

DOI: 10.1007/978-3-032-13898-9_47