Rotor Design, Analysis and Experimental Validation of a High-Speed Permanent Magnet Synchronous Motor for Electric Turbocharger

We developed a high-speed surface mounted permanent magnet synchronous motor (SPMSM) and a pulse width modulation (PWM)-driven inverter for a turbocharger with an additional electrically driven compressor (TEDC). These systems operate at 70 000 rpm and are intended to fit 1.6-L diesel vehicles to reduce turbo lag to within 0.4 s. There are key issues in the design of rotors for SPM type machines. To prevent the PM from scattering during high-speed operation, a retaining sleeve is necessary in the rotor. Several studies have reported on rotor design and the effect of retaining sleeve materials, but no papers have applied appropriate modeling and analysis to composite material sleeves. In this study, a specialized tool was used to obtain accurate results for a composite material sleeve. The results of theoretical analyses and finite element analyses (FEA) of rotors with metallic and composite sleeves were compared, considering various stress sources such as interference fit, centrifugal force and temperature gradient. In addition, rotor dynamics and transient response analyses were performed using the proposed models to verify structural stability and response time. The proposed rotor was assembled with the stator and tested in connection with the 1.6-L diesel engine. It was confirmed that the transient acceleration performance was improved by 49.14%.