Ultra-High-Speed Permanent Magnet Synchronous Motors in Fuel Cell Air Compressors

Abstract

Driven by the rapid development of automotive fuel cells, compact and lightweight system demands require upgraded centrifugal air compressors, as conventional high speed motors at 50,000–80,000 rpm within 15 kW fail to meet current specifications. Since motor size and weight are dominated by torque, raising the rotational speed to improve power density has become the mainstream direction for ultra high speed permanent magnet synchronous motors (HSPMSMs), targeting over 100,000 rpm and 30 kW for fuel cell air compressor applications. This paper presents an 18-slot 2-pole HSPMSM with parallel magnetization, which achieves 35 kW rated power at 100,000 rpm. Electromagnetic performance, rotor mechanical strength, thermal behavior and rotor dynamics are systematically optimized by simulations and experiments.