Analytical PM Eddy Currents Loss Evaluations in Inverter-Fed Slotless Machines Induced by SVM Control Using Polar Coordinates Formulations

Abstract

Space vector modulation (SVM) is a widespread method for controlling PM machines. However, the switching harmonics contribute to eddy current losses in the magnet region. In the analytical modeling of slotless PM machines, the inverter model is reduced to overlook the actual modulation and neglects many higher-order harmonics. This is the first time the full implementation of an experimentally validated analytical SVM has been applied to analytical PM eddy current loss evaluations. The inverter model operates synergically with previously developed analytical field formulations. We show that the inverter's output current from SVM control can be conveniently post-processed to be suitable for analytical implementation. Major numerical implementation challenges are highlighted and addressed for the first time. Our work shows a considerable improvement in the precision both when including and excluding the eddy currents reaction field. Nevertheless, the models' limitations are also emphasized. Finally, the code implementation of the models is made available in the reference list, yielding full reproducibility.

Analytical PM Eddy Currents Loss Evaluations in Inverter-Fed Slotless Machines Induced by SVM Control Using Polar Coordinates Formulations