Transient analysis of multiphase PM motor-drives by non-linear modeling

This paper proposes a technique to evaluate the electrical transients of multiphase permanent magnet motor through non-linear dynamic modeling. The non-linear model makes uses of functions generated by magneto-static finite element analysis, stored in look-up tables and used by a dynamic simulator (“off-line” co-simulation). This approach takes into account the effects of saturation and rotation on the inductance, usually neglected in such kinds of machine. In the same time it requires less computation time and/or hardware resources respect to the on-line co-simulation, making faster the virtual prototyping of the machine. The case study refers to a 5-phase permanent magnets motor for aircraft flap actuator controlled through the brushless DC technique. The electrical dynamics of each phase is simulated by independent voltage model and current models. A comparison between the described approach and the usual constant-inductance model is shown, providing a clear idea of the increase of accuracy available with the proposed method.