Analysis of the enhanced effect of modulation of monotonic magnetic ring double-modulated three-rotor coaxial magnetic gear and its multi-objective optimization

Magnetic gears, utilizing permanent magnet fields for contactless power transmission, offer significant advantages for wind power applications, including no mechanical loss, elimination of lubrication, and inherent overload protection, addressing key limitations of conventional gearboxes. However, their adoption is hindered by common topological drawbacks: weak magnetic field modulation, low torque density, structural complexity, magnetic saturation, and excessive flux leakage. To overcome these limitations, this study proposes a modulation-enhanced monotonic magnetic ring double-modulated three-rotor coaxial magnetic gear. Simulation analysis first compared modulation schemes and validated the proposed gear’s feasibility against a traditional coaxial design. Subsequently, single-factor and Plackett–Burman screening tests identified critical factors significantly influencing torque performance. These factors were then analyzed using Box–Behnken testing, establishing a corresponding response surface model. Following model accuracy verification, multi-objective optimization was performed. Results demonstrated substantial improvements: torque density increased by 19.05%, inner rotor torque fluctuation reduced to 2.74%, and outer rotor torque fluctuation reduced to 2.24%. A trade-off was observed, with intermediate rotor torque fluctuation rising to 17.8%. This work presents a novel structural concept for magnetic transmission design, highlighting the enhanced performance of the proposed topology and underscoring the significant potential of advanced magnetic gears in future wind power transmission systems.