Automotive electric motors, generators, and actuator drive systems with reduced or no permanent magnets and innovative design concepts [Special section intro.]

The Theme: Due to environmental and energy concerns, electric vehicles (EVs) and hybrid electric vehicles (HEVs) are gaining increased attention. At the heart of the drive system of these vehicles is the electric machine and drive. For these applications, high power density, high torque density, wide speed range, and efficiency are of primary importance. To meet these demands, interior permanent magnet (IPM) machines have been widely used. However, IPM machines use rare earth permanent magnets (usually NdFeB) in their structure. The price of these type of rare earth permanent magnets has increased by orders of magnitude in the past several years. Due to the high cost and limited supply of this material, the use of IPM machines in HEV applications is now being challenged. In fact, many researchers are working on other machines that can compete with IPM machines in terms of size, efficiency, power, and torque density. With consideration of the above, and timeliness of this important topic, this Special Section aims to collect the most recent research in electric machines with less or no rare earth permanent magnet material in their structures that are suitable for automotive applications. Topics of this Special Section are limited to electric machines and drives with EV and HEV applications. Machine technologies that are of interest include, but are not limited to: