Analysis and optimization of boost converter parameters in internal model-based control of voltage source converter-based AC microgrids

This paper investigates the integration of distributed energy resources (DERs) in microgrids (MGs) through two-stage power conversion structures consisting of DC-DC boost converter and DC-AC voltage source converter (VSC) subsystems. In contrast to existing investigations that treated the DC-link voltage as an ideal constant voltage, this paper considers the non-ideal dynamic coupling between both subsystems for completeness and higher accuracy, which introduces additional DC-side dynamics to the VSC. The analysis shows parameters of the boost converter's power model that impact stability through the DC-link, and carefully selecting these parameters can mitigate this effect on stability and improve the dynamic performance across the DC-link. Hence, an optimization framework is developed to aid in selecting adequate boost converter parameters in designing a stable voltage source converter-based microgrid (VSC-MG). The developed optimization framework, which is based on particle swarm optimization, considers the dynamic coupling between both subsystems and is also effective in avoiding inadequate boost converter parameters capable of propagating instability through the DC-link to the VSC. Simulations are performed with the aid of MATLAB/Simulink to validate the theoretical analyses.