Influences on the Accuracy of Torque Calculation for Permanent Magnet Synchronous Machines

In this work, the influences on the torque generated by permanent magnet synchronous machines are identified to provide approaches to improve the accuracy of torque calculation. By analyzing the torque generation mechanism, basic machine parameters influencing the generated torque are identified. The machine torque is split into different components, i.e. synchronous, reluctance, and parasitic torque components. The parasitic component results from non-linearities such as saturation. In a second step, environmental and operational conditions influencing those basic parameters are determined. Based on this analysis, the remanence flux density of the permanent magnets, the magnetization behavior of the soft-magnetic material, and the iron losses are selected for the study. Two traction drive machine designs are used in the parameter study. The machine torque is evaluated by performing 2D magnetostatic Finite-Element simulations of the investigated machine designs. The results show quantify the interdependencies between the torque components and the model parameters. The significance of the influence of the parameters on the accuracy of the torque calculation is discussed.