谐波旋转磁场注入法抑制PMSM过调制区转矩脉动

This article proposes torque ripple reduction methods that inject a harmonic rotating magnetic field (RMF) in the overmodulation (OVM) region of permanent magnet synchronous motors (PMSMs). Two methods are proposed: one injects harmonic voltages at the output of a dq-axis current controller in the rotor reference frame (RRF), and the other superimposes a harmonic phase onto the rotor angle used during coordinate transformation. The dominant torque harmonics in the OVM region are derived from spatial harmonics and double Fourier series (DFS) of the inverter pole voltage, and are mitigated using multiresonant (MR) controllers incorporating frequency prewarping to compensate for discretization error caused by a limited sampling frequency. Additionally, their effects on inverter reference voltage vectors (RVVs) and output voltage vectors (OVVs) are analyzed both mathematically and graphically in the OVM region, and their feasibility is verified. Experiments on a 160-kW interior PMSM (IPMSM) under practical driving conditions in the OVM region confirm the effectiveness of the proposed methods, achieving up to 33% torque ripple reduction and 60% mechanical vibration reduction while preserving the same average torque without modifying current references.