Computationally efficient steady-state finite element simulation of multiphase PM AC machines

In this study the authors propose a generalised procedure for computationally efficient steady-state finite element (FE) simulation of symmetrical multiphase permanent magnet (PM) AC machines with an arbitrary number of phases. The procedure is based on newly derived general equations for phase waveform reconstruction that fully exploit the phase symmetry of multiphase electrical machines. This result can be used to reconstruct the full electrical period of any phase waveform from the smallest possible number of magnetostatic FE simulations executed within the minimum angular displacement of the rotor. Reconstruction of phase waveforms is done during post-processing and does not contribute to the execution time of FE simulations. The applicability of the proposed method is demonstrated by deriving specific equations for two-phase, three-phase, five-phase and six-phase machines. Results of classical time-stepping and newly proposed computationally efficient FE simulation are presented for four rotor PM flux switching machines with the different number of phases. Obtained results show that the relative reduction of simulation time increases with the number of machine phases.