Dear Colleagues,

We would like to invite you to contribute to this Special Issue on the design and control of high-performance electric machines. The technical requirements of machines, such as power density and efficiency, are continually increasing. There are also a broad range of growing demands including environmental considerations, sustainability, cost, and ethical factors, which often require the limits of materials to be pushed even further. Papers exploring combinations of these factors are encouraged.

This call has a particular interest in those papers focusing on high-performance through high-speed operation, particularly with a peripheral rotor surface speed of > 150 m/s. Increasing rotational speed has been a traditional method for increasing power-density, but its combination with physically larger rotors generates a specific set of speed-related challenges for designers to overcome, across a broad multi-physics spectrum.

Accurate high speed-dependent loss calculation, including iron losses, AC copper losses, and PWM considerations, as well as mitigation across all components is a critical electromagnetic subject. These increased losses reduce efficiency and increase the thermal challenges. This is exacerbated by the complexities of high-speed rotating fluid flows and the relatively smaller convective surfaces per unit power. Motor topology selection and material choice must be considered alongside cost implications. Mechanical analysis for heightened static stresses, dynamics, materials, manufacturing arrangements and techniques are welcome, with a further desire for machines which have been fully prototyped and verified experimentally.

A non-exhaustive list of potential topics includes:

• High-speed loss characterization
  • PWM Losses
  • AC Copper Losses
  • Stator and Rotor iron losses
  • PM eddy current losses
• High-speed efficiency improvements
  • Machine topology
  • Winding layout and methodology
  • Active material usage
  • Design trade-off and optimisation
• Mechanical Design
  • PM retention
  • Hollow shafts
  • Novel bearing arrangements and selection
• Prototyping
  • Manufacturing
  • Experimental performance and loss verification
• High-speed rotor dynamics
• Cooling of high-speed machines
  • Rotating turbulent flows
  • Rotor cooling
  • Spray cooling
  • Heat pipes

Dr. Peter Connor
Dr. Adam Walker
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Machines is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• electric machines
• multi-physics analysis
• thermal management
• loss mitigation
• high-speed machines
• AC losses
• materials
• mechanical stresses
• electrical machine manufacture