DERs integration in microgrids using VSCs via proportional feedback linearization control: Supercapacitors and distributed generators

Abstract

This paper presents an exact feedback linearization control strategy for voltage source converters (VSCs) applied to the integration of distributed energy resources (DERs) in smart distribution systems and microgrids. System dynamics is represented by an average nonlinear model which is transformed algebraically into an equivalent linear model by simple substitutions, avoiding to use Taylor's series or another equivalent linearization technique. The equivalent linear model preserves all characteristics of the nonlinear model, which implies that the control laws obtained are completely applicable on its nonlinear representation. Stability analysis is made using the passivity-based technique. The exact feedback linearization control in combination with passivity-based control (PBC) theory guarantees to obtain a global asymptotically stable controller in the sense of Lyapunov for its closed-loop representation. The effectiveness and robustness of the proposed methodology is tested in a low-voltage microgrid with a photovoltaic system, a supercapacitor energy storage (SCES) device and unbalance loads. All simulation scenarios are conducted in MATLAB/SIMULINK environment via SimPowerSystem library.