Open AccessFast calculation of eddy current losses caused by pulse‐width modulation in magnets of surface‐mounted PM machines based on small‐signal time‐harmonic finite element analysis
Author(s) -
Zhu Sa,
Hua Wei
Publication year - 2020
Publication title -
iet electric power applications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.815
H-Index - 97
eISSN - 1751-8679
pISSN - 1751-8660
DOI - 10.1049/iet-epa.2020.0299
Subject(s) - eddy current , pulse width modulation , finite element method , harmonic , magnet , electromagnetic coil , rotor (electric) , harmonic analysis , piecewise , physics , interpolation (computer graphics) , modulation (music) , voltage , acoustics , materials science , electronic engineering , engineering , mathematics , frame (networking) , mathematical analysis , mechanical engineering , quantum mechanics , thermodynamics
This study presents a novel method for fast calculating the eddy current losses (ECLs) caused by pulse‐width modulation (PWM) harmonic voltages in the permanent magnets (PMs) of surface‐mounted PM synchronous machines (SPMSMs) with distributed windings or concentrated windings. Based on the small‐signal models of the SPMSMs, the functional relationships between the high‐frequency harmonic voltages (HFHVs) in the rotor reference frame and the corresponding ECLs are investigated with the time‐harmonic finite element analysis (THFEA). Instead of using complex analytical PM ECL models, the relationships are directly established with some numerical methods, such as the Gauss quadrature and the piecewise cubic Hermite interpolation method, based on the results from THFEA. With the functional relationships, the total PM ECL caused by all the HFHVs is simply calculated by summing the ECL generated by each harmonic component in the spectra of the PWM voltage in the rotor reference frame. Both two‐ and three‐dimensional (2D and 3D) models of the SPMSMs are calculated. Besides, to further reduce the needed steps of 3D THFEA, an equivalent 2D THFEA method using modified PM conductivities under different‐axis HFHV excitations is proposed. The merits of the proposed method are validated by comparing with the traditional time‐stepping finite element method.