Modeling and design optimization of PM AC machines using computationally efficient - finite element analysis

Computationally Efficient - Finite Element Analysis (CE-FEA) is detailed and demonstrated on a design optimization study for a sine-wave current regulated Interior Permanent Magnet (IPM) machine. In CE-FEA symmetries of electric and magnetic circuits of AC machines are fully exploited to minimize the number of required magnetostatic solutions. CE-FEA employs Fourier analysis and is capable of accurately estimating major steady-state performance parameters (average torque, profiles of cogging torque and torque ripples, back emf waveforms, and core losses), while preserving the main benefits of detailed finite element analysis. Significant reduction of simulation times is achieved (approx. two orders of magnitude) permitting a comprehensive search of large design spaces for optimization purposes. In a case-study IPM machine, three design variables, namely, stator tooth width, pole arc, and slot opening are used to optimize three performance parameters, namely, average torque, efficiency, and full-load torque ripple.