Design and Analysis of Voltage-Stabilized Small STATCOM

This study aims to reduce the capacity of the LCL filter for the miniaturization of the STATCOM. The problem here is that the current response is worse when the back impedance of the grid is high compared to that of the LCL filter. In other words, the harmonics of the current are increased. In order to improve the current response, a phase leading compensator can be used. However, since the LCL filter has a current resonance characteristic, a compensator may increase the effect of the resonance and might cause control instability. In this study, we confirmed by numerical simulation that feedback control with a phase leading compensator and a notch filter connected in series in addition to a conventional PI compensator prevents the harmonic increase caused by the deterioration of the current response.