Enhanced Proportional-Resonant (PR) Controller with Negative Decoupling for Weak Grids

During the last decade the penetration of grid-connected RES systems has increased exponentially forcing power conversion industry to design new advanced controllers in order to comply with new requirements. The current control loop is a critical layer to improve the RES performance especially in weak grid and remote micro-grids. Based on the resonant control concept, this paper presents a modified structure for the PR controller which results advantageous when implemented on RES systems, as it allows the system to perform as a PI in the synchronous reference frame during the dynamic state of the controller. This paper also deals with the analysis of the decoupling terms in the stationary reference frame, which will add an improvement to the dynamic response of the controllers. The proposed controller will be analyzed, discussed and finally validated by means of simulation analysis.