Reduction of Rotor Loss in High-Speed Electrical Machines With a Novel Composite Sleeve

The rotor eddy-current loss caused by high frequency current and magnetic field changes is very high in high-speed permanent magnet machines (HSPMM). This is one of the important factors contributing to the overheat of the PMs. Since the sleeve loss is the main component of the overall rotor loss, it is widely concerned in HSPMM. In this paper, a novel composite sleeve is proposed to reduce the rotor loss. The proposed sleeve is applied to a 90kW, 16000r/min PM machine, the total rotor loss and temperature rise are respectively decreased by 44.5% and 18.7% (25.2°C) compared with a conventional carbon fiber sleeve. Furthermore, the rotor maximum stress is obtained and validated to be within the safe range.