Three-Phase Enhanced Phase-Locked Loop (PLL) in Simulink

This Simulink-based three-phase enhanced phase-locked loop (PLL) is designed to achieve accurate phase synchronization during asymmetric grid faults. The system architecture incorporates three key components: 1) Configurable asymmetric grid voltage source: A flexible power supply module with adjustable parameters to simulate various grid asymmetry conditions, implemented using Simulink's Three-Phase Programmable Voltage Source block with custom asymmetry control logic. 2) Conventional phase-locked loop: The baseline PLL implementation employs a standard dq-frame synchronization technique, typically using a synchronous reference frame (SRF) PLL structure with PI controller regulation for fundamental frequency tracking under normal grid conditions. 3) Enhanced phase-locked loop: The advanced PLL module incorporates improved synchronization algorithms such as dual second-order generalized integrator (DSOGI) or decoupled double synchronous reference frame (DDSRF) techniques. These methods implement sophisticated filtering and decoupling mechanisms to maintain stable phase locking during severe grid unbalance conditions. Through this comprehensive design approach, the system achieves robust phase synchronization under asymmetric grid faults. The enhanced PLL module significantly improves system performance and adaptability by implementing advanced signal processing algorithms that ensure stable and reliable phase tracking even during challenging grid conditions.