Research on Torque Ripple Suppression of Halbach Array Machine Based on High-order Harmonic Cosine Function Magnet Pole Arc Trimming

A new method that combines cosine pole arc trimming and high-order harmonics is proposed to address torque ripple issues in Halbach-array permanent magnet synchronous machines during high-performance operations. Tunable harmonic-modification functions are introduced at the edges of magnetic-pole slots based on a synergistic optimization strategy combining “multi-objective global optimization and local geometric modification” to effectively suppress torque ripple without significantly reducing the average torque. By focusing on a 9-slot, 6-pole Halbach machine, CHC-3, CHC-5, and CHC-7 schemes are designed and analyzed, and a cosine pole-arc contour modification equation is derived to parametrically describe the magnet’s surface profile. Among the selected schemes, CHC-3 demonstrates highly effective torque ripple suppression by approximately 20-25%, decreasing the average torque by only about 1%.