A New Two-Phase Stationary-Frame-Based Enhanced PLL for Three-Phase Grid Synchronization

In this brief, a new two-phase stationary-frame-based enhanced phase-locked loop (TPSF-EPLL) is proposed for detecting the amplitude, phase angle, and frequency of a three-phase grid. The differential equations of the proposed TPSF-EPLL are originally derived based on minimizing the cost function with a gradient descent algorithm. Moreover, the system structure, the design guidelines of each parameter in both frequency and amplitude loops, and the stability analysis of the TPSF-EPLL are presented. The main advantage of the TPSF-EPLL is that it requires less calculation since transformation into a rotating reference frame is not involved, and all the calculation is performed in a two-phase stationary frame. Experiment results of steady state and dynamic performance of TPSF-EPLL are presented and compared with some classical PLLs to verify the validity of the theoretical analysis and its advantages.