Synchronization Stability Analysis Under Ultra-Weak Grid Considering Reactive Current Dynamics
Bin Hu, Ling Zhan, Subham Sahoo, Liang Chen, Heng Nian, Frede Blaabjerg
Abstract
The synchronization stability of grid-following converter has attracted extensive attention. It has been reported that the transient synchronization behavior during a grid fault is dominated by the phase-locked loop (PLL), while the current loop is always approximated as a unity gain. Nevertheless, this letter notices that the reactive current dynamics will also influence the synchronization stability under ultra-weak grid, which increases the risk of losing synchronization, and causes the PLL output frequency to be outside the limitation. Accordingly, a refined fourth-order model is proposed to reveal the above underlying mechanism and quantify this coupling effect.
Topics & Concepts
Synchronization (alternating current)Phase-locked loopControl theory (sociology)GridStability (learning theory)Transient (computer programming)Computer scienceCoupling (piping)Fault (geology)Current (fluid)EngineeringMathematicsTelecommunicationsControl (management)GeologySeismologyOperating systemElectrical engineeringArtificial intelligenceJitterGeometryMachine learningChannel (broadcasting)Mechanical engineeringMicrogrid Control and OptimizationIslanding Detection in Power SystemsPower Systems and Renewable Energy