Frequency-Domain Analytical Prediction of PWM-Induced Current Harmonics in Slotless Surface-Mounted PM Synchronous Machines

• Published in: IEEE transactions on energy conversion Vol. 39; no. 2; pp. 1059 - 1074
• Main Authors: Zhang, Xiaolong, Haran, Kiruba S., Krein, Philip T., Garces, Luis J.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01-06-2024; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Amplitude modulation; carrier harmonics; equivalent circuit; Equivalent circuits; Error analysis; Frequency analysis; Frequency domain analysis; Harmonic analysis; Harmonics; Inductance; Integrated circuit modeling; Permanent magnet (PM) machines; Permanent magnets; Power harmonic filters; pulse width modulation; Synchronous machines; Systems design; total harmonic distortion; Voltage
• ISSN: 0885-8969; 1558-0059
• DOI: 10.1109/TEC.2023.3337191

Slotless surface-mounted permanent magnet (PM) synchronous machines with high pole numbers generally have relatively low inductance, which will lead to significant current harmonics under PWM-driven inverters. Current harmonics can cause additional losses and torque ripples, severely impacting temperature rises and mechanical vibrations. Accurate prediction of current harmonics is crucial for machine performance calculation and drive system design. This article proposes a frequency-domain analytical method to predict the current harmonics with high fidelity equivalent circuit models. The harmonic prediction method is validated experimentally under a wide range of operating conditions and improves the prediction accuracy by up to 75% compared to the existing analytical modeling methods. The prediction error using the proposed method is generally maintained below 10%, making it an effective tool for practical applications.