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Stjepan Stipetic

Stjepan Stipetic
University of Zagreb, Faculty of Electrical Engineering and Computing (FER) · Department of Electric Machines, Drives and Automation

Assistant Professor

About

46
Publications
39,233
Reads
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550
Citations
Citations since 2016
30 Research Items
476 Citations
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
2016201720182019202020212022020406080
Additional affiliations
July 2008 - December 2014
University of Zagreb
Position
  • Researcher

Publications

Publications (46)
Article
Full-text available
Scaling laws are used when the size of a certain machine design with known performance needs to be adjusted for a new application with known requirements, or when a machine design is geometrically scaled and one needs to determine its performance. Scaling laws derived in this study allow one to quickly and accurately recalculate parameters of a geo...
Conference Paper
Full-text available
This paper presents a general approach to the optimized design of a series of interior permanent magnet motors with the same lamination cross section. A concept of a referent and particular design has been introduced and analytical expressions which relate the principal machine parameters for the referent and particular machine have been derived. T...
Conference Paper
Full-text available
This paper presents summarized electromagnetic and thermal design of interior permanent magnet motor for a low-floor tram TMK 2200. Motor geometry is optimized for maximum torque density using differential evolution algorithm. The influences of winding configuration on power losses and thermal transients in the motor during one driving cycle of the...
Article
Full-text available
This paper presents a finite-element (FE) method approach to calculation of the common-mode choke (CMC) impedance over a wide frequency range. The proposed method involves a 3-D electrostatic FE calculation of each turn-to-turn and turn-to-core capacitance, and their usage as electric circuit lumped parameters in the 3-D time-harmonic magnetic FE c...
Article
Full-text available
This study presents an accurate and computationally efficient finite-element (FE) calculation and modelling methods for the simulation of symmetrical steady-state load conditions for synchronous generators. For that purpose, two iterative methods are presented, implemented and compared. Those are Newton's iterative method and the relaxation paramet...
Conference Paper
Full-text available
A synchronous reluctance machine has been selected and optimized for commercial vehicle power takeoff application. The meta-modeling optimization process has been covered in detail. To reduce execution time, skewing has not been included in the optimization workflow. The penalty is elevated torque ripple of unskewed design (13.9%), which has been m...
Article
Full-text available
Nowadays, due to the confidence in modeling tools and rapid product iteration, electric machine designers primarily rely on simulations. This approach reduces time and cost and is very useful when comparing different machine topologies. The prototype stage usually comes after the depletion of all simulation resources. When designing a synchronous r...
Article
Full-text available
In most cases, the search for the optimal design of an electrical machine is closely related to its 2D radial cross section. When optimizing a 2D cross section, special attention must be paid to the geometry and to the definition of the parameters along with their boundaries. Even if properly bounded, complex geometries generated by optimization al...
Article
Full-text available
The first step in the synchronous reluctance machine design is the selection of rotor flux barrier type. The literature provides various barrier construction methods with a common goal of reducing parametric complexity. However, too excessive simplification can lead to decreased performance, while overly complex geometries tend to increase optimiza...
Article
Full-text available
This paper presents a novel methodology and experimental setup for measuring iron loss under pulse width modulated (PWM) power supply using a ring sample of the ferromagnetic laminated core. A power converter based on silicon carbide (SiC) technology was used to achieve high switching frequencies and near ideal output voltage. The unique feature of...
Article
Full-text available
Although rare earth materials are the critical component in high torque density permanent magnet machines, their use has historically been a commercial risk. The alternatives that have been in the recent industry focus are synchronous reluctance machines (SyRM). They have lower torque density but also relatively low material cost and higher overlo...
Article
Full-text available
The papers in this special section intends to collect ideas and recent advances from the global community in the field of improving robustness to uncertainty in the modelling, analysis and design of electric machines and drives, making possible the development of appropriate models for such components. When modelling electromechanical devices, elec...
Conference Paper
Full-text available
While electric vehicle (EV) technology has been established in passenger vehicle sector, commercial multipurpose vehicle (MPV) penetration is strictly related to the niche end-markets, like medium-duty, short-haul and last mile applications. Some of the examples of short-haul applications are electric multipurpose vehicles (eMPV) like refuse, hook-...
Article
This paper analyzes an engineering problem of adjusting the rated current of a synchronous reluctance motor to match the rated current of a commercially available inverter. This situation may occur when a synchronous reluctance motor is optimally designed for maximum torque per ampere (MTPA) operation using standard IEC stator frames for induction...
Conference Paper
Full-text available
The volatilities in the permanent magnet price have raised interest within the automotive industry for finding substitute electric machine designs. The proposed alternatives are synchronous reluctance machines (SyRM) and its derivatives, assisted synchronous reluctance (PMASR) machines. These solutions rely on high reluctance torque thus theoretic...
Article
Full-text available
This paper proposes the novel scalable model of synchronous permanent magnet and synchronous reluctance machines which combines ultra-fast scaling laws with saturated flux-linkage and loss model. The scalable model is used for fast and accurate calculation of efficiency/loss maps and can also be used for drive cycle analysis including calculation o...
Article
Full-text available
The paper presents a novel method for optimal sizing of traction motors based on vehicle level targets. The method employs a scalable electric machine model inside the multi-objective optimization algorithm. A reference motor geometry is scaled in axial and radial directions in the optimization routines according to the values of the design variabl...
Article
Full-text available
This paper presents a method for reducing computational time in constrained single objective optimization problems related to permanent magnet motors modeled using computationally intensive finite element method. The method is based on Differential Evolution algorithm. The principal approach is to interrupt the evaluation of inequality constraints...
Conference Paper
Full-text available
This paper proposes the application of analytical scaling laws on existing saturated flux-linkage and loss models for synchronous permanent magnet and reluctance machines. This scalable model is used for fast and accurate calculation of efficiency/loss maps and can also be used for drive cycle analysis including energy consumption. The scalable mod...
Article
Full-text available
This paper presents a comprehensive approach to design of series of permanent magnet assisted synchronous reluctance motors using combined analytical and finite element calculations. A global optimisation metaheuristic algorithm (differential evolution) is utilised in order to achieve optimal design in terms of maximum torque per volume with numero...
Conference Paper
Full-text available
Design of high performance, low cost and clean propulsion systems requires multiple disciplines such as physics, mathematics, electrical engineering, mechanical engineering and specialisms like control engineering and safety. This paper details the program of EU FP7 Multi-ITN project ADvanced Electric Powertrain Technology (ADEPT) and presents a re...
Conference Paper
Full-text available
This paper presents an overview of methodology for usage of mathematical optimization procedures e.g. optimization algorithms to achieve optimal design of an electrical machine. A special care must be taken in order to handle parameter definition, boundary constraints, constraint functions, model feasibility and computationally expensive calculatio...
Article
Full-text available
This paper defines the scaling laws for synchronous permanent magnet machines which include three separate procedures: rewinding, axial scaling, radial scaling. The derivation of scaling relations is based on the requirement that the magnetic fields in the scaled model should be the exact images of the fields in the referent model. The exact equati...
Article
Full-text available
A simplified model of transformer hysteresis curve utilized for calculation of core losses is presented. It incorporates eddy current losses and hysteresis losses into the same hysteresis curve thus simplifying a set of equations used for solving the magnetic circuit. The parameters of the hysteresis curve model are determined by evolutionary optim...
Article
Full-text available
The paper presents the method of selection, calculation and measurements of generator that is built into the new transformer test station. The three phase cylindrical synchronous generator 800 kVA, 200 Hz with special damper bars is most suitable to be used as a power supply for testing of single-phase and three-phase power transformers. The emphas...
Article
Full-text available
The selection of a three phase synchronous generator most suitable to be used as a power supply for testing of single-phase and threephase power transformers is described in the paper. The emphasis is on the analysis of the armature winding connection and sizing of the damper winding due to unsymmetrical load of a generator in the temperature rise...
Article
Full-text available
Paper addresses some of the problems related to direct surface temperature measurement of a salient pole synchronous generator excitation winding in rotation. Excitation winding temperature is used for determining the dynamic limit in a PQ diagram. The paper also addresses procedures of improving the accuracy of surface temperature measurement usin...
Article
Full-text available
This paper presents an analytical model of a common-mode choke suitable for accurate calculation of the choke impedance over a wide frequency range. The model consists of lumped parameters (resistances, inductances, and capacitances) related to individual turns of the coils wound on the core. It takes into account the mutual interactions between th...
Article
Full-text available
A new measurement method for infrared (IR) surface temperature measurement of excitation winding in rotation is presented. The method is experimentally verified on a 400-kVA salient pole synchronous generator. This method uses an industrial IR thermometer which represents an alternative to expensive fast IR thermometers or cameras. The target appli...
Conference Paper
Full-text available
This paper addresses some of the problems related to direct temperature measurement of synchronous generator excitation winding in rotation. Excitation winding temperature is used for determining the dynamic limit in a PQ diagram. The paper also addresses procedures of improving the accuracy of surface temperature measurement using the DS18B20 digi...
Conference Paper
Full-text available
Excitation winding temperature is used for determination of the dynamic limit in the P-Q diagram of a synchronous generator. The surface temperature of an excitation winding can be measured by an infrared (IR) thermometer. Due to rotation, the IR thermometer absorbs thermal radiation from the excitation winding on the salient pole and from the inte...

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Projects

Project (1)
Archived project
ADEPT is a unique European industrial and academic project focused on electric propulsion systems. As a Marie Curie Initial Training Network, ADEPT will train 12 early stage researchers (ESRs) and 2 experienced researchers (ERs) in this field, raising their academic standards and practical engineering skills as well as developing a powerful research network across Europe. A further goal is to produce a versatile and comprehensive development platform for E-propulsion systems. This is both a virtual (based on models and simulation) and a real (involving demonstration hardware as well as Hardware-in-the-Loop based test systems and control software) development environment for E-propulsion systems. An intimate involvement in all aspects of the collaboration (research, secondments, experiments etc.) along with an extensive training program in a wide range of related fields (electromagnetics, thermal, mechanical, vibroacoustics, control, vehicle integration) allows the ADEPT ESRs and ERs to develop their technical proficiency and complementary skills such as project management and entrepreneurship. The industry-academia partnerships within ADEPT further facilitate the application of scientific results of the ADEPT program within E-propulsion and other industrial products and solutions.