Research on microgrids grid-connected inverter system based on improved PLL

In this paper, we study a grid-connected inverter system based on improved PLL. Firstly, the power quality of the microgrid grid-connected system is analyzed from different angles. Then, the structure of the the loop and its phase-locking principle are briefly introduced, and the limitations of the software loop are indicated. Subsequently, the improved scheme of using second order generalized integral to extract positive order components and eliminate harmonics is analyzed in detail. Finally, we build a simulation model using MATLAB to improve the phase locked loop, and it shows that the adopted phase locked loop can correctly and quickly phase locking during the grid voltage distortion.