Design and Experimental Validation of a High-Speed Electric Turbocharger Motor Considering Variation of the ${\boldsymbol{L}}/{\boldsymbol{D}}$ Ratio

The commercialized electric turbocharger (ETC) made by Valeo includes a high-speed switched reluctance motor (SRM), ball bearings, impeller, and controller. SRMs are generally very noisy and have low efficiency (70%) at high speed. No ETC has yet been commercialized that includes a permanent magnet (PM) motor. The Korea Electrotechnology Research Institute, Changwon, South Korea, is developing a high-speed surface PM type of synchronous motor and a pulse width modulation-driven inverter. This system operates at a power density of 3 kW/kg at 100000 r/min and is intended to fit 1600 cc diesel vehicles to reduce turbolag to within 0.5 s. The design and analysis of the PM synchronous motor (PMSM) for the ETC have been successful by considering the electric and mechanical performance using multiphysics analysis. Validation by experiment was performed and matched within 1% error in terms of the efficiency. Design, analysis, and experiments with the PMSM for ETC applications were conducted successfully by utilizing an action-reaction torque sensor and the resistance load test method.