Hybrid and full electric technologies are fast emerging in vehicles and mobile working machines, where electric machines and internal combustion engines are used together to power the systems. Permanent magnet (PM) technology plays an important role here despite the high magnet prices. This paper theoretically and empirically studies the design principles of PM synchronous machines (PMSMs) for hybrid applications, where a high starting torque and a wide field weakening range are needed. Several embedded-magnet PMSM magnetic circuit topologies are considered as possible candidates. A 10-kW PMSM prototype was built and tested. Experimental results verify the theoretical considerations well.

A permanent magnet traction motor integrated with a planetary gearbox is studied. A machine of this kind can be employed as a propulsion motor in off-road machines like agricultural tractors that have to produce either very high traction forces at low speeds or reach higher traveling speeds at lower torques. In principle, a constant power curve as a function of speed is desired, which means that the output torque of the drive system should be inversely proportional to the operating speed of the off-road machine. Such driving conditions are challenging as the electric motor has to be heavily overloaded at the lowest speeds. Therefore, it is essential to accurately evaluate not only the electromagnetic performance but also the thermal performance of the machine. This paper studies the integration principles of an electrical machine and a planetary gear. The integration poses some new challenges to the design. For example, also the lubrication and cooling can, and, in practice, must be integrated into the system. The thermal performance of the motor and cooling with the lubrication oil of the gear were analyzed. The long-term tests with the oil cooling system were carried out to verify the successful integration.

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He became an Associate Professor of electrical engineering in 1993 and a Professor of electrical machines and drives in 1997 with LUT. He is currently the Head of the Department of Electrical Engineering, LUT, where he is engaged in research and development on electric motors and electric drives. His current interests include different synchronous machines and drives, induction motors and drives, and solid-rotor high-speed induction machines and drives.

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Since 2009 she has been with Konecranes, Finland. Her research interests include electrical machines and drives, energy-efficiency design, and hybridization. Juho Montonen was born in 1988 in Joutseno, Finland. He received the Master of Science (M.Sc.) degree from Lappeenranta University of Technology (LUT), Finland in 2012 and Bachelor of Science (B.Sc.) in 2011. He is currently doctoral student in LUT. He is doing the research concerning about electrical machines and drives. His research work focuses on permanent magnet motors, especially those which are used in different kinds of traction applications. Vitaliy Sizonenko was born in 1989 in Tomilino, Russia, received the Master of Science (M.Sc.) degree from Moscow Power Engineering Institute (MPEI), Russia and from Lappeenranta University of Technology (LUT), Finland in 2012 (double degree programme), the Bachelor of Science (B.Sc.) degree from MPEI in 2010. Pia Lindh received the D.Sc. (Tech.) degree in 2004 from Lappeenranta University of Technology. She currently works as a researcher teacher at the Department of Electrical Engineering. Her research interests include a wide range of electrical machines and drives, permanent-magnet machines and traction applications in particular. Juha Pyrhönen, a Member of IEEE, was born in 1957 in Kuusankoski, Finland, received the Doctor of Science (D.Sc.) degree from Lappeenranta University of Technology (LUT), Finland in 1991. He became an Associate Professor of Electrical Engineering at LUT in 1993 and a Professor of Electrical Machines and Drives in 1997. He is currently the Head of the Department of Electrical Engineering, where he is engaged in research and development of electric motors and electric drives.His current interests include different synchronous machines and drives, induction motors and drives and solid-rotor high-speed induction machines and drives.