Application of Phase Shifting Technique for Reducing the Magnetomotive Force Space Harmonics of Tooth Concentrated Windings

Abstract

Permanent magnet machines with fractional slot concentrated windings are very attractive for low-speed direct-drive applications due to their compactness, cost effectiveness, and high efficiency. However, one of the key challenges of using concentrated winding configurations is the high content of space harmonics in the air-gap magnetomotive force distribution, which can lead to undesirable effects such as high rotor losses, vibrations, and noise. In this article, the phase shifting technique is investigated to deal with the harmonic content of such windings. An example of application is given for a three-phase winding with a number of slots per pole per phase = 2/5. It is shown that by using this simple technique, one can cancel some of the harmful magnetomotive force space harmonics without decreasing the winding factor of the torque producing harmonic. Further, calculations revealed a significant improvement in machine performances when compared to the conventional design.

Keywords:

• tooth concentrated winding
• space harmonics mitigation
• magnetomotive force
• permanent magnet synchronous machines
• phase shifting

Additional information

Notes on contributors

Nassim Bekka

Nassim Bekka was born in Algeria in 1990. He received his M.S. in energy and reliability from the Montpellier University of Science, France, and his Ph.D. from the University of Nantes, France, in 2012 and 2015, respectively. His research interests include the design, modelling, and optimization of low-speed high-torque permanent magnet synchronous machines.

Didier Trichet

Didier Trichet is a professor at Polytech’Nantes and IREENA Laboratory, France. He received his M.S. and Ph.D. in electrical engineering from Nantes University, France, in 1995 and 1999, respectively. He joined the Polytechnic School of Nantes University in 2002, where he worked as an assistant professor in the Department of Electrical Engineering. He was author or co-author of more than 50 articles in peer-reviewed scientific journals and international conferences. His research interests cover mathematical and computer modeling of electromagnetic and thermal phenomena applied to low-frequency devices, such as innovative induction heating processes, power network, and high-efficiency fuel cell power systems.

Nicolas Bernard

Nicolas Bernard was born in France in 1971. He received his M.S. in electrical engineering from the University of Poitiers (France) in 1995, followed by the “Agrégation” instructors credential in 1997 and his Ph.D. from the Ecole Normale Supérieure de Cachan (France) in 2001. Since 2004, he has held the post of assistant professor with the IREENA Laboratory in Saint-Nazaire. His research activities are mainly flywheel energy storage and the design, modeling, and optimization of new topologies for electromagnetic actuators.

Mohamed El Hadi Zaïm

Mohamed El Hadi Zaïm is a professor in the Department of Electrical Engineering at Polytech’Nantes, in Nantes University (France). He is employed as a researcher in the IREENA Laboratory in Saint-Nazaire where he was the head of electromechanical conversion team. He is engaged in the research and development of electrical machines design. He is especially active in the fields of permanent magnets and solid-rotor high-speed synchronous machines, and reluctance machines for low-speed applications.