Resource-Aware Grid-Forming Synchronization Control: Design, Analysis and Validation

Abstract

This paper presents a power-synchronization loop scheme for renewable power generation operated in Grid-Forming (GFM), which considers the DC-connected resource limitations. Under conditions where the resource might not be able to provide the Alternating Current (AC) power required by the GFM structure (e.g. lack of resource), the DC voltage might drop to concerning low values, leading to potential converter shutdowns. The proposed resource-aware GFM (RAGFM) is capable of regulating the DC bus while maintaining a GFM behaviour towards the AC network. The control is analyzed for the two operating modes of the inverter-based resources (IBRs).In the first, the resource provides constant power, whereas the second mode considers that the resource operates with a power reserve. The tuning of the different gains of the suggested control scheme is defined based on the maximum virtual inertia that the converter can emulate without exceeding its design limitations. In addition, RAGFM is benchmarked against other synchronization methods, including a detailed dynamic analysis. The different synchronization methods are analytically and dynamically compared. Finally, the RAGFM is implemented in an experimental set-up where its capabilities are verified.