Electric vehicle (EV) technology is continually advancing, and the efficiency of electric motors plays a significant role in enhancing vehicle performance. A recent study published on March 14, 2025, unveils novel advancements within the field of electric motor design, focusing on the Interior Permanent Magnet Synchronous Motor (IPMSM). This research introduces the I2V type rotor topology, which aims to improve the sine waveform quality of air gap flux density—a structural change expected to yield higher torque density and lower torque ripple.
The study indicates the prominent challenges electric motors face, such as torque ripple and harmonic distortions, particularly pronounced at low operational speeds. These issues primarily stem from the uneven air gap magnetic fields within traditional IPMSMs, which negatively affect performance and vehicle comfort. By optimizing rotor designs through 2D parameterized finite element analysis (FEA), the authors propose solutions to these long-standing issues.
According to the authors, the I2V type rotor configurations demonstrated considerable improvements: "The no-load air gap flux density of I2V type proposed in this paper have the lowest total harmonic distortion rate (THD)." The findings show how varying the opening angle and pole arc angle of the first layer of permanent magnets significantly impacts the electromagnetic efficiency of these motors, with the I2V design achieving reduced harmonic distortion rates compared to both V and IV type rotors.
One of the central innovations explored within this research is the incorporation of circular flux isolation holes within the I2V type rotor. This design aims to alleviate the torque ripple issue—defined as the fluctuation of torque output during operation, which can lead to undesirable vibrations and noise within electric vehicles. The study concludes, "Aiming at problems... this paper proposes... to reduce torque ripple," enabling significant improvements. The prototype using this new design showcased impressive results, achieving a torque ripple reduction ratio of 67.3% under rated velocity conditions.
The authors performed experimental assessments on the prototype’s torque performance across various conditions, demonstrating consistency with FEA results. The tests reveal when the motor operates at full capacity—allowing for peak currents up to 500A—the observed torque outputs align closely with the predicted FEA values, validating the design's efficiency and reliability. Indicating the strength of this I2V design, they state, "Experimental verifications are conducted on the torque, external characteristics," which offered insights from real-world testing.
Through layers of optimization and computational modeling, the I2V rotor type has not only emerged as superior to traditional designs, but its potential applications for improving electric vehicle technology could be transformative. The study hopes to inspire future enhancements and more sustainable motor solutions for automotive applications. The results reinforce the need for continuous innovation and exploration of advanced motor design strategies to support the rapidly growing electric vehicle market.
With the push toward decarbonization and increased adoption of electric mobility, the advancements exemplified by the I2V design exhibit the promise of achieving more efficient performance characteristics, thereby facilitating the widespread acceptance of EVs. By optimizing existing technology, researchers and engineers alike can contribute to overcoming barriers within the electric propulsion domain, ensuring enhanced user experience and environmental benefits.