An Improved Frequency Estimation in Droop Control for Power Converter Interface

Converter-based resources are increasingly vital in power systems, particularly for integrating renewable energy sources. These resources are synchronized with the grid through software, increasing the significance of precise angle and frequency synchronization. Traditional synchronization techniques rely on Phase-Locked Loops (PLL), which are known for their drawbacks. This paper introduces an improved Half-Cycle CRT (HC-CRT) frequency estimation based on AC frequency estimation using the Cauchy Residue Theorem (CRT). Furthermore, the research applies the traditional PLL, CRT frequency estimation, and HC-CRT frequency estimation in a phase-lead droop control strategy. This paper is to compare these three frequency estimations and develop an improved droop control system for a hybrid power system (HPS) to provide fast frequency and voltage support after disturbances on the AC grid.