Amortecimento ativo híbrido utilizando corrente do capacitor e tensão do ponto de conexão para inversor com filtro LCL

Abstract

This work deals with a hybrid active damping of LCL grid-tied inverters. This hybrid method uses the point of common coupling voltage and the capacitor current as feedforward in the control action. Mathematical modelling of the system is carried out. The analysis of the impact of the choice of the gains in the frequency response and in the closed-loop poles positions is presented. Moreover, the impact of modelling or neglecting the implementation delay is evaliated and it is shown that the system becomes unstable quicker for an equal gain. A methodology for choosing the gains was developed verifying the damping of the pole closest to the unit circle. At last, it is shown the impact of changing the gains and the grid inductance in the control actions and the converter and grid currents.