Internal Model Control design applied to single-phase grid-connected inverters

This paper presents the design of the One-Degree of Freedom Internal Model Control structure (1-DOF IMC) applied to a single-phase grid-connected inverter. It is presented the mathematical model of the inverter and its LCL filter, used to project the 1-DOF IMC controller, and it is analyzed the internal feedback compensation corresponding to the decoupling of grid voltage provided by a feedforward strategy. In order to establish a comparison base, the grid connected system is also evaluated using a Proportional-Resonant Controller (P-Res). Simulations and experimental results of both controllers are presented, which allows the comparison between the 1-DOF IMC and P-Res control performances.