Convex Optimization-based Vector Current Control Design for Grid-connected Packed E-Cell Inverters

This paper proposes a robust H ∞ vector current control strategy for grid-tied single-phase nine-level Packed ECell (PEC) inverters under grid impedance uncertainty. A multi-input multi-output polytopic model is developed for the grid-tied PEC with the grid impedance uncertainty. By virtue of this novel model, a robust H ∞ vector current control framework is then proposed. The current controller design problem with desired performance specifications is formulated as a convex optimization problem. The main feature of the proposed control approach is that it guarantees robust stability and satisfactory performance against the uncertainty in grid impedance. The effectiveness of the proposed control strategy is evaluated by simulation case studies and experimental results.