A Simple Approach to Enhance the Performance of Complex-Coefficient Filter-Based PLL in Grid-Connected Applications

In recent years, a large number of three-phase phase-locked loops (PLLs) have been developed. One of the most popular ones is the complex coefficient filter-based PLL (CCF-PLL), which benefits from a sequence selective filtering ability. This feature enables the CCF-PLL to selectively reject/extract disturbances before the PLL control loop while maintaining an acceptable dynamic behavior. The aim of this letter is presenting a simple yet effective approach to enhance the standard CCF-PLL performance without requiring any additional computational load.