Fast Calculation of Strand Eddy Current Loss in Inverter-Fed Electrical Machines
Xinggang Fan, Dawei Li, Wubin Kong, Longfei Cao, Ronghai Qu, Zhouping Yin
Abstract
This article investigates the complex slot leakage magnetic field and the strand eddy current loss in windings of inverter-fed electrical machines. It shows that the magnetic saturation and the pulsewidth modulation (PWM) harmonics could have a significant influence on the slot leakage magnetic field, and thus may influence the eddy current loss. To consider these effects while reducing the computation burden, a semianalytical strand eddy current loss calculation method is proposed based on the slot leakage field calculation by a two-dimensional (2-D) magnetostatic finite-element method (FEM) and a 2-D analytical high-frequency eddy current loss expression. The frozen differential permeability method and the linear time-harmonics FEM are used to fast calculate the PWM-induced slot leakage field with the magnetic saturation considered. Besides, a conductor position model is used to extract the conductor coordinates and leakage field information for calculating the eddy current loss. The proposed method is implemented and experimentally validated on a surface-mounted permanent magnet electromechanical actuator fed by a PWM inverter for aircraft application. It shows high calculation accuracy and fast calculation speed, which is suitable for motor-inverter system design and optimization.