Hybrid Impedance-Based Controller Design of Grid-Connected Converter for Whole-System Stabilization of Grid-Connected DC Microgrids

This project a hybrid impedance-based controller design from the whole-system stabilisation perspective. Based on the concept of hybrid impedance, a stability criterion considering the AC and DC coupling dynamics is proposed as a benchmark for the controller design of GCCs. In addition, with the help of linear matrix inequalities, a step-by-step algorithm is developed to automatically and efficiently tune the control parameter to achieve the desired design criterion. The effectiveness of the proposed method is verified through case studies in simulation by using Matlab/Simulink Software. The further comparison study also shows that the proposed method has a stronger whole-system stabilisation ability compared to some reviewed methods. In some specific tests, the proposed method can limit the current THD to about 2% compared to other methods that cause the THD to exceed 20%

Keywords: DC microgrid, grid-connected converter, impedance model, whole-system stabilisation, linear matrix inequality.