Development of 150000 r/min, 1.5 kW Permanent-Magnet Motor for Automotive Supercharger

This paper discusses an optimum design of an ultra high-speed permanent-magnet synchronous motor (PMSM), which is applied to a supercharger of an automotive engine. Although the motor is driven by an inverter with a 12-V DC bus voltage due to an automotive power source, it achieves the maximum rotating speed of 150000 r/min and the rated output of 1.5 kW. Since the power source strictly restricts the motor terminal voltages and the fundamental operating frequency is as high as 2500 Hz, it is significant to pursue further reduction of the synchronous impedance in the motor, paying attention to its permeance coefficient. In the paper, a FEM-based electromagnetic field analysis is conducted, followed by a theoretical discussion on the optimum machine design. In addition, the mechanical structure is discussed to produce a real machine. The developed prototype has a variety of unique features from electrical and mechanical viewpoints, and some experimental test results are presented to demonstrate its potential.