Robust Control Parameters Design of PBC Controller for LCL-Filtered Grid-Tied Inverter

Owing to the strong robustness against system parameter changes and external perturbations, the passivity-based control (PBC) has been widely adopted in grid-tied inverter (GTI). However, for a PBC-based GTI with LCL-filter, there are three damping gains and two interactively coupled-feedforward terms in the control loop, resulting in the controller design challenge for engineers. In order to help electrical engineers to well design the PBC controller for LCL-filtered GTI, a new design of the damping gains is proposed, by limiting the inherent steady-state error of grid-injected current. Furthermore, the state observer is also adopted to reduce the number of sensors. The robustness against the parameters shift and wide grid impedance variation is also addressed. The effectiveness of the proposed control design strategy will be verified through experimental results on a 3 kW/3-phase/110 V experimental lab setup.