Model reduction and feedback design based on singular perturbation method applied to a lumped DER-microgrid model

Abstract

In the context of microgrids, the distributed energy resources (DERs) are interfaced through an LCL output filter with the rest of the microgrid. The dynamic model of this filter and the lumped model of the microgrid constitute the set of differential equations employed to design the controller that allows the integration of DER units within the modern power systems. For those control strategies based on cascade structure; shunt capacitor voltage (inner) and droop (outer) controllers, it is important to specify under which conditions the model reduction is authorized. In this work, the singular perturbation method is used to derive the conditions that allow a model reduction of the output filter. In addition, two case studies are presented to illustrate the applicability and the possibility of model reduction.