This paper describes a novel auxiliary drive concept for application in electric transportation that ensures optimal efficiency and reliability for long life operation. A case study on different auxiliary drive solutions is carried out on a vehicular air compressor example for comparative result assessment. The results show clear benefit of variable frequency drive utilizing GaN FETs in a 3-level NPC inverter topology with a permanent magnet synchronous machine for the investigated application. The proposed concept ensures the highest efficiency in operation with small and moderate load, light and balanced loading without heavy starts, and the significantly reduced wear out of components. As a result, the auxiliary drive system can be designed with downsized components, at the same time achieving more reliable field operation with increased lifetime.