Harmonic Current Suppression in Twelve-Phase PMSMs via Cascade Extended State Observer and Vector Resonant Control

A harmonic suppression strategy for twelve-phase Permanent Magnet Synchronous Machines (PMSMs) is proposed by combining a Cascade Extended State Observer (CESO) and a Vector Resonant Controller (VRC). The CESO compensates non-periodic disturbances in real time, while the VRC selectively suppresses harmonic components. Based on Vector Space Decomposition (VSD), the method enhances disturbance rejection and current decoupling. Experiments verify that the proposed scheme reduces the Total Harmonic Distortion (THD) from 1.59% to 0.89%, significantly improving current waveform quality and torque smoothness, showing strong potential for high-performance multiphase motor drives.