Active Damping: An $\mathcal {H}_\infty$ Model Reference Approach

This paper focuses on the design of an active-damping controller that shapes the dynamics of an LCL grid connected voltage source converter (VSC) to mimic an L-filter connected VSC. This makes possible to use simpler classical proportional plus resonant or proportional plus integral controllers design methods to regulate the grid current with minimum penalties in both performance and stability margins. The active-damping design follows a model-reference approach and is synthesized through a (sub)optimal H
_∞
algorithm. The controller uses the grid current and point of common coupling voltage, although it allows the selection of a different set of measurements. Effectiveness of the method is demonstrated with timeand frequency-domain experimental results.