Comparison between a Series-Hybrid Variable-Flux Memory Motor and a Rare-earth Interior Permanent Magnet Synchronous Motor

This paper compares a series hybrid variable-flux memory-motor, which uses AlNiCo9 magnets in series with rare-earth permanent magnets, with an equivalent conventional rare-earth IPMSM. While pure memory motors have been proven to have higher efficiency than conventional IPMSMs in the high-speed region, the technology suffers from low torque and power during high-speed operations. Thus, hybrid memory motor technology has been introduced. It has been reported that the series-hybrid technology can improve high-speed torque and power. Although the technology has caught the electric vehicle industry’s attention, the literature lacks a detailed comparison between conventional rare-earth IPMSMs and series-hybrid variable-flux motor technologies. Thus, this paper compares a series-hybrid variable-flux IPMSM with an equivalent conventional rare-earth IPMSM regarding torque, efficiency, power, power factor, and drive cycle. This comparison is made on a 6-horsepower motor scale using finite element analysis (FEA) software and experimental results.