Evaluation of current reference generation methods for a three-phase inverter interfacing renewable energy sources to generalized micro-grid

In this paper, different methods of deriving the grid current references for a three-phase renewable energy based inverter connected to generalized micro-grid system are compared. The three-phase micro-grid voltage is considered to have unbalance as well as harmonic contamination. Primarily the p-q and FBD theory based methods are compared in terms of different specifications like manifestation of DC link side ripples, computational power required for implementation and restriction on the power circuit topology. Another method, equal phase active power sharing is also compared with these well known methods and its effect on the power circuit topology is also investigated. The comparisons are carried out based on the mathematical analysis and the experimental results under different operating conditions.