A Novel Compensation Strategy for Active Power Filtering

Aiming at the limitations of the traditional active power filter (APF) harmonic compensation strategy, this paper proposes a new active power filter compensation method. By establishing the equations of magnetic potential balance between the harmonic currents of the primary and secondary sides of the transformer, combined with the harmonic current inversion model, the harmonic components of the primary side are mapped directly, which reduces the dependence on voltage sensors in the detection link. The proposed method connects a combination of capacitive capacitors and inductors to the transformer's secondary side tapping point, which cooperates with active and passive compensation devices to optimise the dynamic response and capacity utilisation of the compensation current. Finally, MATLAB-Simulink simulation experiments show that the method can significantly reduce the total harmonic distortion rate (THD) of the load current from 29.16% to 6.28%, while maintaining a stable capacitive voltage on the dc side (about 410V), and the tracking accuracy of the compensation current reaches 93.21%. The theoretical analysis and experimental results verify the advantages of this strategy in terms of harmonic suppression, system stability and engineering adaptability, providing a new solution for power system harmonic management.