An Improved Current Harmonic Decomposition for IPMSM Based on Multiple Virtual Three Phase Systems Construction

To enhance the control capability of harmonic currents in the interior permanent magnet synchronous motors (IPMSM), this paper proposes an improved current harmonic separation method based on multiple virtual three-phase winding construction. Firstly, this paper analyzes the limitations of traditional current harmonic separation methods based on virtual winding construction and provides the constraints on the number of virtual windings and their spacing angles required to achieve separation of current harmonics at any frequency. Then, taking the 5th, 7th, 11th, and 13th harmonics as an example, four virtual windings with phase intervals π/15 are constructed for realizing their individual separation, and the spatial distribution law of each current harmonic there in the αβ coordinate frame is analyzed, and the harmonic characteristics are extracted with the help of the multiple synchronous rotating frame transformation (MSRFT). Finally, the current harmonics were effectively controlled in the dq coordinate frame. The experimental results show that compared with the traditional method, the proposed method can achieve independent separation of current harmonics. The extracted current harmonic characteristics exhibit smaller fluctuations, and when controlling the urrent harmonics, it can reduces the additional introduction of higher-order harmonic content.