Improving Transient Stability of Power Synchronization Control for Weak Grid Applications

Abstract

Power synchronization control (PSC) has a promising potential to be used in interface converters of large-scale renewable generations operating under weak-grid condition. This paper presents a modified PSC-based control structure that provides an enhanced dynamic response, reinforced synchronization, and reduced vulnerability against grid transients. By utilizing a back-calculation scheme, the active power reference in the synchronization loop of PSC is configured to be adapted to the grid transients for avoiding loss of synchronization (LOS). Furthermore, the proposed control structure prevents power-injection collapse (PIC) and mitigates the dc current components of the converter caused by transients in weak grids. Performance and feasibility of the proposed control structure are highlighted and verified by simulation of various scenarios and operating conditions.