IMPACT OF SALIENCY RATIO VARIATION ON TORQUE PERFORMANCE IN INTERIOR PERMANENT MAGNET SYNCHRONOUS MOTOR

Abstract: This paper studies effects of changes in saliency ratio on the electromagnetic torque performance of Interior Permanent Magnet Synchronous Motors (IPMSMs). The saliency ratio (q-axis to d-axis inductance ratio) Lq/Ld has a decisive impact on the formation of both the magnet and reluctance torque in the IPMSM. A MATLAB dq-axis dynamic equations simulation model was developed to assess the torque response with different saliency ratios. The results reveal that as the saliency ratio increases, the average and peak torque increase on the whole, mainly because the contribution of reluctance torque becomes considerable. A motor produces only magnet torque at the saliency ratio of unity, and the reluctance torque becomes dominant as Lq becomes larger than Ld. It can be seen by the time-waveform of the electromagnetic torque higher torque values obtained by larger saliency ratio. Besides the torque improvement, the simulation showed that the torque ripple increased slightly which means a trade-off between performances and smoothness. Additionally, when analyzing the stator current dynamics it was observed that as the saliency value increases iq remains rather the same, although id is outlined with more dynamics, resulting in profound transients in higher saliency ratios. The simulation also generated characteristic curves of saliency ratio versus average torque, peak torque and torque ripple. These results validate that the saliency ratio greatly affects the performance and dynamic characteristic of IPMSMs. This knowledge can be used to optimize rotor design for high performance electric drive applications. The MATLAB model developed in this work is a flexible platform for design assessment and can also be used for testing control strategies or for validating experimental outcomes. Keywords: Electromagnetic torque, interior permanent magnet synchronous motor, MATLAB simulation, saliency ratio, stator currents. Title: IMPACT OF SALIENCY RATIO VARIATION ON TORQUE PERFORMANCE IN INTERIOR PERMANENT MAGNET SYNCHRONOUS MOTOR Author: Dominica C. Ihem, Rachael I. Ovbiagele, Chidiebere D. Obasi, Uchendu U. Nlerum International Journal of Novel Research in Engineering and Science ISSN 2394-7349 Vol. 12, Issue 1, March 2025 - August 2025 Page No: 46-54 Novelty Journals Website: www.noveltyjournals.com Published Date: 24-June-2025 DOI: https://doi.org/10.5281/zenodo.15727876 Paper Download Link (Source) https://www.noveltyjournals.com/upload/paper/IMPACT%20OF%20SALIENCY%20RATIO%20VARIATION-24062025-5.pdf