DESIGN OF PHASE-LOCKED LOOP OF GRID CONNECTED CONVERTER BASED ON ACTIVE DISTURBANCE REJECTION CONTROL

In a high proportion of renewable energy infiltration penetration，the power system presents low inertia damping characteristics. The traditional synchronous reference coordinate phase- locked loop （SRF- PLL） based on PI controller is more vulnerable to the fluctuation of new energy，resulting in poor phase-locked output results，which leads to a series of oscillation problems of grid- following converter. A phase- locked loop based on first- order linear ADRC（LADRC- PLL）is proposed. By comparing and analyzing the frequency domain characteristics of first-order LADRC-PLL and traditional phase-locked loop based on PI controller（PI-PLL），the advantages of its disturbance rejection performance are explained. A simple parameter design method is proposed to simplify the parameter design of PLL. Under the same bandwidth scale comparison，it shows the limitations of the application of high- order LADRC in the phase-locked loop of grid connected converter. The simulation of PLL and the experimental results based on hybrid active neutral point clamped（HANPC）grid connected converter show that the proposed LADRC-PLL has more accurate phase locking results in disturbed environment，and is more suitable for new power systems with high proportion of renewable energy. © 2023 Science Press. All rights reserved.