An Inverter-based Harmonic Oscillation Suppression Strategy with Active Damping

With the use of large amounts of secondary clean energy, it has increased burdens for the power grid and brought more serious harmonic problems. The network resistance composed of multiple grid-connected inverters and local loads is very complex, and their mutual coupling even causes harmonic resonance, which will bring abundant harmonic disturbances. To address the above problems, this paper proposes a control method of active damping for grid-connected inverters, which effectively suppresses harmonic components by separating the harmonics of voltage and current at the grid-connected point and controlling them through feedback, thus introducing virtual resistance and conductance to the harmonic circuit model. The device only performs feedback suppression for harmonic currents, so its capacity is low and it is flexible to use without affecting the work of other grid-connected inverters. The validity and correctness of the approach as presented in the paper has been preliminarily demonstrated by using the MatLab software.