Fully-integrated high-speed IM for improving high-power marine engines

In this study, electrical machine technologies are compared comprehensively for a hybrid turbocharger used with a high-power marine engine. It is required for the machine to operate in a thermally aggressive environment, with turbine exhaust temperatures in excess of 600°C. Furthermore, it is required to both generate from the extra exhaust energy (turbo-compounding) at high-engine loads as well as a motor for low-engine loads during slow steaming. The application investigated translates to a machine featuring both high-power (150 kW) and high speeds (25-50 krpm), together with a considerable constant power-speed region. In this study, induction machines (IM), permanent magnet machines and switched reluctance machines are compared taking into account a number of aspects including the thermal performance, torque ripple, converter volt-ampere rating, and cost. In light of the technical and market requirements, the IM featuring new materials is prototyped and tested for the application in a representative environment.