Lidija Petkovska, PhD
Lidija Petkovska has received BSc EE Degree from the Faculty of Electrical Engineering, University of Belgrade, and MSc EE and Doctoral Degree from the Faculty of Electrical Engineering, Ss. Cyril and Methodius University of Skopje.
Her field of interest encompasses wide problems of electrical machines, which are principally in three areas: novel electrical machines, electric drives and control, and in particular numerical FEM field computations of electrical machines, design, optimization, simulation and testing.
Until 2008 Lidija Petkovska was full professor with Faculty of Electrical Engineering and Information Technologies from Ss. Cyril and Methodius University of Skopje. From 2009-2013 she was full professor with International Balkan University in Skopje, serving from 2011 as Dean of the Faculty of Graphic Design. During her educational career, she was delivering lectures on numerous courses of all three cycles of study, guiding more than 150 diploma projects, 8 master and 4 doctoral theses. Another important part of her activities is participation in total 28 international and/or domestic Science&Research, Research&Development, Industry oriented and Educational projects, acting in 11 as principal researcher and team leader.
Professor Lidija Petkovska has an international reputation on all of her research work. She has published as author and co-author 295 papers in conference proceedings and 76 peer reviewed papers in scientific journals, among which 35 are with impact factor. Lidija Petkovska in 1995 published a book “Micromachines”, dealing with small and special electrical machines, still the only one in the country.
As a recognition to her scientific work she was delivering guest lectures for PhD students at the University of Lodz, Poland and for MSc students at the University of Maribor, Slovenia. Also, at ISEF’2013 Conference presented an invited paper, while at ISEF’2019 she was one of the panellist at the session entitled “Optimal design, metamaterials, 3D printing” giving a speech on “Shape synthesis and innovative motors”
Lidija Petkovska is a member of ISCs of prestigious international conferences, acting as a peer reviewer and also chairing more than 70 sessions. She was organiser and Chair of the world-wide known ISEF’2013 conference, and from 2006 is founder and chair of SAEM conference, now in the 8th edition – SAEM’2022, which will be held in North Macedonia.
Lidija Petkovska is Senior Member of IEEE and member in two societies: Power and Efficiency Society – PES and Magnetic Society. She is also member of Polish Society of Applied Electromagnetics – PTZE (PSAE), honorary member of Macedonian Section for power electronics, drives and control MAK-ZEEPU, member of CIGRE International and the Chair of CIGRE-North Macedonia B4 Committee.
State-of-the-Art Technology for Innovative Electric Motors
Electric motor is one of the few inventions that shaped electrical technology the most. The very beginning of the electric motor is found exactly two hundred years ago, in 1821. However, over the time many significant changes in the technology have been moving forward, opening new frontiers for innovative electric motors. In particular, new trends in e-mobility as the developments of EV (Electric Vehicles) and HEV (Hybrid Electric Vehicles), forced new requirements related to size/weight of the drive and resulted in awesome innovations for in-wheel electric motors, thus creating substantial solutions.
The first question to be answered is “What makes an electric motor innovative?” First, it is an innovative design topology and use of novel materials, then an innovative production technology and, the most recently, new state-of-the-art manufacturing processes. A design engineer of electric motors is seeking for answers to the following: (i) What are structural/shape choices that define novel motor topology and make the motor better-performing? (ii) What are the most effective novel materials for obtaining the best of each component/shape in the design layout? (iii) How to extend the limits of the motor’s performance reached today? (iv) What are novelties in the electric motor design? (v) How is an innovative motor manufactured?
Another important aspect to discuss is certainly the state-of-the-art production technology. The most recent 3D printing technology developments, have added a huge value to the designing, prototyping as well as manufacturing processes. The broad spectrum of production applications has been unlocked. The significant reduction of time and money consumption, required for the stage of prototyping, led to cost-effective massive motor production. The laser technology is growing, becoming more workable and affordable, such that additive manufacturing (AM) from 3D printing of only parts of an electric motor has been moved to the printing even the whole motor structure. Using 3D computer aided design (CAD), and having in hand 3D scanners, additive manufacturing allows the creation of objects with precise geometrical shapes, built layer by layer with adding multi-material, opposite to classical manufacturing when the excess of material is subtracting.
The AM technology is broadly divided in three types: (i) sintering whereby the material is heated without being liquified to create complex high resolution objects; (ii) melting where metal powders are melted so that the particles stick together and shaped; (iii) stereolithography, which uses the process of photopolymerisation, to create torque-resistant ceramic parts. In the talk few selected processes are discussed and elaborated: Fuse Deposited Material (FDM), Selective Laser Sintering/Melting (SLS/M), StereoLitography Apparatus (SLA).
To present days several pioneering research centres throughout the world have reported successful applications. At the end of this talk, more interesting applications are presented. It is started with the earliest practical implementation of 3D printing for the purpose of electric motor prototyping in e-mobility, where only some parts of the motor topology have been manufactured. However, the real challenge for electric motor designers is producing the whole motor by using AM, the task still rather complicated. The first fully 3D-printed stator, developed by an enthusiastic group of electrical engineers from Chemnitz University, Germany and premiered in 2018 at ‘Hannover Messe’ – the trade fair, will be presented and explained.
Keywords: Innovative motors, E-mobility, Novel materials, 3D-Printing, Additive manufacturing (AM), Fuse Deposited Material (FDM), Selective Laser Sintering (SLS), StereoLitography Apparatus (SLA)