基于改进型重复控制器的永磁同步电机电流谐波抑制方法研究

The repetitive control technique is widely adopted in the field of harmonic suppression, due to its low total harmonic distortion. However in the motor control system, when the ratio of the system sampling frequency to the current harmonic frequency is not an integer, the resonant frequencies of the repetitive control deviate from the practical harmonic frequencies of motor current. As a result, the performance of these systems will be significantly degraded using the conventional repetitive control. In this paper, an improved repetitive controller based on Lagrangian interpolation method was proposed, which adopted a fractional-order delay link based on Lagrange interpolation. The fractional-order delay link can approximate the delay function of the frequency ratio's fractional part, and then the resonant frequencies of the repetitive control will match the practical harmonic frequencies well. In order to further reduce the tracking error of the current harmonics, the low-pass filter located inside the traditional repetitive control module was removed and the stability of the system was ensured by adding a phase compensator. The validity and effectiveness of the proposed method were demonstrated by simulation and experimental results.