Loss analysis of permanent-magnet motor considering carrier harmonics of PWM inverter using combination of 2-D and 3-D finite-element method

In this paper, we propose a novel method to calculate harmonic losses of permanent-magnet motors driven by pulsewidth modulation inverters. First, two-dimensional (2-D) nonlinear time-domain finite-element analysis is applied to estimate the harmonic rotational magnetic field at the air gap of the motor. Next, the three-dimensional frequency domain finite-element analyses at each remarkable harmonic field are carried out with the results of the harmonic gap flux densities obtained by the 2-D analysis. Using this procedure, the magnet eddy-current loss caused by the carrier harmonics of the inverter can be calculated with practical computer resources.