Development of a High-Speed, Permanent Magnet, SiC-Based Drive With Integrated Input Filters

AC Input filters in high speed drives are generally large and can even exceed the mass of the motor. This article firstly seeks to reduce the volume and overall mass of the drive through integrating the input inductors with the magnetic circuit of the machine. The magnetic circuits are shared without cross-coupling through careful choice of the filter and motor pole numbers. Finite Element Analysis (FEA) is used to check that normal operation of the base PM machine is not affected by the integration and a demonstrator drive is built. Compared with discrete AC filters, the integration of the LCL filter inductors has given a very large volume reduction of 87.6%, producing a much more compact envelope than with the conventional filter inductors. Through a holistic approach to a combination of electrical, mechanical and thermal aspects of the drive system, the integrated drive exhibits significant mass and volume advantages over conventional discrete motor drives. Two major technical issues related to the power electronics development of the IMD are presented in the paper: investigation of a bus bar solution to manage a large number of winding terminals introduced from integrated LCL filters, and a compact SiC device based power electronics design.