Multi-parameter Optimization of 400V e-Compressor Motor using Magnet Sizing and Flux Barrier Topology using JMAG Simulation

Permanent Magnet Synchronous Motor (PMSM) for 400V Compressor uses a rare earth magnet (NdFeB). Rare earth magnets have the advantage of high torque, high power density and high efficiency, however, pose a challenge of increased motor cost.. The requirement is to use less quantity of magnet in the motor design, which should serve the purpose of providing the needed starting torque at the worst case operating temperature scenario (-40 deg C). The objective of the present work is to design a PMSM with optimal design of magnets and to evaluate its performance. Also, to generate an efficiency map for the optimized PMSM compressor capable of achieving an efficiency of 92% at the rated operating point.The PMSM should be covering all the peak and continuous operating regions within the specified limit of peak line current consumption. JMAG Designer® is used to parameterize the rotor, stator and coil profile and to perform the efficiency analysis at speed priority mode. The JMAG tool helped to maximize the efficiency with different rotor profile, and coil profile at both peak and rated torque region. Different magnet profiles and number of coil turns are tested with improvement in flux concentration in the rotor and minimise the material weight as objectives. Finally the target efficiency of 92% @ speed of 3000 rpm @ Torque of 3.23 Nm is achieved and it is giving better performance compared to previous generation motors. JMAG results are well correlated with real time physical test results and hence 50% proto tooling cost reduction was achieved and the final design selected is currently in the testing phase.