Best Electric Machine sees opening for active-rotor motors as rare-earth worries grow

Best Electric Machine says rising concern over China-dominated rare-earth supply chains is reviving interest in active-rotor electric machine designs for vehicles, aircraft, industry and defense. The Boston company argues modern control electronics may finally make symmetric motor architectures practical without rare-earth permanent magnets. Why it matters: - Best Electric Machine says electric motor makers are under pressure to reduce dependence on rare-earth permanent magnets as supply-chain and geopolitical risks intensify. - The company argues active-rotor architectures could offer a path to high performance without relying on strategically sensitive materials. - The issue affects automotive, aerospace, industrial and defense systems, where motor choice shapes cost, complexity, performance and material sourcing. What happened: - Best Electric Machine announced renewed attention on historical research into doubly-fed, active-rotor electric machines. - The Boston-based company said decades of laboratory work showed symmetric active-stator and active-rotor designs could achieve higher air-gap utilization than conventional passive-rotor machines. - Best Electric Machine said practical commercialization was limited by the control electronics available at the time. - The company pointed to its bibliography of active-rotor research as a summary of more than six decades of related academic and laboratory work. - Best Electric Machine directs readers to more information on its website. The details: - Frederick Klatt, chief technology officer at Best Electric Machine, said the historical barrier was real-time control of the interaction between active stator and active rotor systems under line disturbances, load changes and shaft perturbations. - The company said electromagnetic theory was not the main obstacle; control capability was. - Best Electric Machine said modern advances in high-frequency electromagnetics, digital signal processors, power semiconductors, sensors, embedded computing, adaptive control algorithms and artificial intelligence may change the commercial case. - The company said roughly 85% of electric vehicles use rare-earth permanent-magnet motor systems. - Best Electric Machine said most transportation, industrial, aerospace and national-security motor systems still rely on passive-rotor architectures such as induction, reluctance, permanent-magnet and wound-field machines. - The company said those systems involve tradeoffs among performance, cost, complexity and material requirements. - Best Electric Machine said its patented SYNCHRO-SYM™ electric machine architecture uses a symmetric active-stator and active-rotor topology. - The company said BRTEC™ stands for Brushless and Sensorless Real-Time Emulation Control. - Best Electric Machine said the design is intended to eliminate rare-earth permanent magnets while increasing electromagnetic utilization and reducing dependence on strategically sensitive materials. Between the lines: - The announcement is as much about timing as technology. - Active-rotor concepts are not new, but the company is betting that current computing and control hardware can solve the problems that kept earlier versions from scaling. - The message also reflects a broader industrial push to hedge against concentrated rare-earth mining, processing and magnet production. - Klatt compared the moment to other technologies that became practical only after electronics and control systems matured, including electric vehicles, fly-by-wire aircraft, active suspension systems and neural networks. What’s next: - Best Electric Machine is urging researchers, industry leaders and government agencies to reexamine active-rotor architectures under current technology conditions. - The company said its development work continues on the SYNCHRO-SYM™ system and BRTEC™ direct AC-to-AC controller technology. - Best Electric Machine said its mission is to deliver high-performance axial-flux symmetric electric propulsion systems without rare-earth permanent magnets. The bottom line: - Rare-earth supply risk is reopening a technical debate that was long considered settled, and Best Electric Machine wants active-rotor motors back on the table.