Extended DQ model of a Permanent Magnet Synchronous Machine by including magnetic saturation and torque ripple effects

Abstract

Nowadays the comfort in passenger transport system is very relevant. One source of noise and vibration is the torque ripple. Torque ripple can be generated by an inappropriate machine control tuning and by the inherent torque ripple of the machine. In permanent magnet machines, the inherent torque ripple is composed by three components: electromagnetic torque, reluctant torque, caused by the winding magnetic field, and reluctant torque caused by the permanent magnet magnetic field, commonly known as cogging torque. In order to assess the torque ripple at each working point, the electromagnetic analysis using a Finite Element Method (FEM) is a very accurate solution. In a dynamic simulation the high computational load is the main drawback of the FEM analysis. To overcome this problem, in this paper the use of a mixed approach is proposed, in which the parameters of a dynamic vector model are previously adjusted using FEM characterization. The aim of this strategy is to do just one complex FEM simulation, so later a quicker dynamic model can be used. In this article, an adjusted dynamic vector model of a Permanent Magnet Synchronous Machine (PMSM) is presented. The inputs of the model are the phase voltages and the rotor position. The outputs are the currents, the flux linkages and the total electromagnetic torque, including all the parasitic components of the torque ripple. The advantages of this model are the reduction of simulation time and the possibility to integrate it in a more general dynamic simulation platform.