Design of a Novel Integrated Motor-Compressor Machine with GaN-Based Inverters

The objective of this paper is to analyze a novel high-speed integrated motor-compressor drive system and investigate the opportunities by using gallium nitride (GaN)-based inverters. The proposed integrated motor-compressor is a combination of electric machine and axial-flow compressor by shaping the rotor pole of the electric machine into airfoils. Hence, the proposed integrated motor-compressor can provide electromagnetic torque and compression function at the same time. As the integrated machine needs to rotate at high speed to achieve high compression ratio, the challenges of high fundamental frequency are addressed. By leveraging GaN-based inverters, the current harmonics distortion is reduced, and high efficiency is maintained at the high-speed operating condition. In this design, a GaN-based inverter is proposed for driving an integrated motor-compressor rotating at 35000 rpm. The electromagnetic performance of the proposed integrated machine is investigated by analytical equations and finite element analysis (FEA). The characteristic parameters, current total harmonic distortion, and the efficiency of the GaN-based inverter are compared with the Si-based inverter.