Multi-physics Filed Coupling Design of High-speed Permanent Magnet Machine for Electric Turbocharging

Electric turbochargers are one of the most cost-effective products for enhancing fuel efficiency in both conventional fuel vehicles (CFVs) and hybrid electric vehicles (HEVs). Benefiting from the increasingly stringent trend of energy conservation and emission reduction, it is predicted that the installation rate of turbochargers will continue to increase in the future. To address the issues of poor calculation accuracy during high-speed operation of electric turbocharger machines, this paper focuses on a 3.2kW and 60,000r/min high-speed permanent magnet synchronous machine (HS-PMSM) for electric turbocharger as the research object. It conducts a study on the multi-physics field coupling design method encompassing the electromagnetic, thermal, stress, and rotor dynamics. This research reveals the coupling mechanisms between various physical fields within the HS-PMSM, further enhancing the machine reliability and performance. Firstly, the working principle of the electric turbocharger machine system is elaborated, and the machine structure and key parameters are presented. Secondly, based on the bidirectional magnetic-thermal coupling method, the machine losses and temperature are studied. Furthermore, the temperature-stress coupling and rotor dynamics of the HS-PMSM are investigated to obtain the variation of the rotor strength under different operating conditions. Finally, a prototyped HS-SPMSM is manufactured and a testing platform is built, where the performance and feasibility of the machine are verified through experiments.