Utilization of Torque Component by Current Harmonics with Limitation of Copper Loss in Dual Three-phase YASA AFPM Machine

To achieve the utilization of torque components by current harmonics and the limitation of copper loss in a dual three-phase yokeless and segmented armature (YASA) axial flux permanent magnet (AFPM) machine, optimized 5th and 7th current harmonic injection is proposed. The torque component generated by the current harmonics is analyzed based on the vector space decomposition (VSD) model of the dual three-phase YASA machine, with consideration of the 5th and 7th harmonics of the open-circuit flux linkage. The optimization of 5th and 7th current harmonics, aiming for maximum torque with limited copper loss (MTLCL), is conducted and compared with existing optimization methods. Subsequently, simulations with and without current harmonic injection are conducted to compare and verify the proposed optimization. The simulation results show that the torque generated by the harmonics in the proposed method is 6.91% higher than that in the existing method, with 5th and 7th open-circuit flux-linkage harmonics of 17.72% and 5.3% of the fundamental component, respectively. A prototype is built, and the experimental results show that the torque component by current harmonics achieves 2.60% of that by the fundamental current with the limitation of copper loss, which further validates the proposed method.