design optimization and testing of high-performance motors

Fabio Luise, Alberto Tessarolo, Freddie Agnolet, Stefano Pieri, Maurizio Scala Brin, Massimiliano Di Chiara, & Matteo De Martin (University of Trieste)

CHALLENGE - The project originates from the need to identify a state-of-the-art technology to meet high-speed motor requirements for the gas process sector that can expand beyond a laboratory setting and be used for continuous industrial production. To meet the very high efficiency, dynamic performance, and reliability standards required by cutting-edge turbomachinery drive applications, a special PM synchronous motor prototype has been developed. 

SOLUTION - This article reports on an industrial research and development (R&D) project to find the best compromise between performance and production cost targets for a special direct-drive turbomachinery application. The development and testing of a 640-kW 10,000-r/min motor prototype characterized by a slotless stator and a Halbach-magnetized, magnetically levitated permanent magnet (PM) rotor is discussed, including the technology selection, the design optimization processes, the machine manufacturing, and testing results. In this study, the multiobjective optimization software modeFRONTIER evaluates the current design fitness based on objective function values and, through genetic algorithms, creates a new set of design variables that identify the design to be analyzed in the next cycle.

BENEFITS - Motor design optimization through genetic algorithms has been presented as a tool to search for the best tradeoff between performance targets and industrial production cost reduction. Overall, the prototype behavior throughout the testing campaign has been successful. Regarding the improvement of cast resin thermal conductivity in the end coil region: casting under vacuum instead of environmental pressure conditions improves the thermal conductivity from 0.5 W/km to approximately 0.8 W/km.