Current-Injected Torque Ripple Reduction With Minimized Iron Loss in PMSMs

This letter presents a new current harmonic injection method to mitigate the inherent torque ripple in PMSMs. In contrast to conventional methods that aim to reduce torque ripple while minimizing copper loss, this letter explores the optimal solution for minimized iron loss. The key of the proposed method involves injecting 6<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i>th <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">dq</i>-axis currents with carefully configured amplitude and phase, resulting in the generation of only (6<italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i>-1)th winding current. This approach effectively avoids a significant increase in iron loss, which is the primary source of additional losses induced by the injected current. The effectiveness of the proposed method is validated through both finite element method and comparative experiments.