Solid High-Speed Synchronous Reluctance Rotor Enabled by Multi-Material Additive Manufacturing

Synchronous reluctance (SynR) motor technology is promising to realize rare-earth material-free electric machines. However, structural challenges limit operation speed and subsequently power density compared to machines with rare-earth permanent magnets. This paper proposes and investigates multi-material additive manufacturing (MMAM) as a key-enabler to realize power-dense SynR machines. It does so by guiding magnetic flux through a solid rotor component by selective placement of magnetic and non-magnetic materials to enable high-speed operation. To validate this concept, samples are manufactured using a MMAM process and experimentally characterized to assess the structural and magnetic properties that can be expected for the proposed rotors. The data is then used in a multi-physics modeling framework to explore the design space of new MMAM rotor concepts. The simulated results in this paper reveal that MMAM technology can enable a 4x increase in rotor speed, resulting in 400 % power density improvements. The MMAM rotors achieved tip speeds of approximately 300 m/s and rotational speeds over 55 kRPM at comparable efficiencies to conventional designs, despite the presence of existing MMAM geometry restrictions. This study ultimately demonstrates that MMAM technology has the potential to enhance SynR machine operation speed and power density, making it a valuable option for high-performance applications.