Inner current loop analysis and design based on resonant regulators for isolated microgrid applications

Inner current and voltage loops are fundamental in achieving good performance of microgrids based on power electronics voltage source inverters. The analysis and design of these loops are essential for the adequate operation of these systems. This paper investigates the effect of state feedback coupling in the design of proportional resonant controllers for these inner loops in voltage source inverters operating in islanded microgrids. It is also shown that the state feedback coupling has an important effect in the performance of the control loops by increasing the steady-state error. A comparison between different types of proportional+resonant controllers is done. Experimental results verify the theoretical assumptions done.