Inner current control loop influence on islanded microgrid dynamic behavior

Abstract

A stable islanded microgrid operation is generally dictated by the adopted control strategy into the system. Droop control and master-slave control are the most used into parallel-connected inverters. However, the choice between the two is often performed in function of their complexity and that of the system configuration. It is rarely achieved in function of the microgrid dynamics. This paper proposes the system dynamics and stability as a criterion for choosing a microgrid control strategy. This is explored into the microgrid composed of photovoltaic and battery energy sources, as well as constant impedance load. The influence of inner current control loop parameters on microgrid dynamics, for both droop control and hybrid V-f and PQ control, is achieved through Small-signal stability analysis. The obtained results determine the proper control strategy from stability limits of two control methods established in the left half complex plane.