Fast LADRC-Type Phase-Locked Loop With Adaptive Extended State Observer
Qi Liu, Li Zhang, Qiang Qian
Abstract
Synchronous reference frame phase-locked loop (SRF-PLL) is widely used in grid-tied applications because of its simple control loop structure. Compared with PI-type SRF-PLL, the linear active disturbance rejection control (LADRC)-type SRF-PLL can achieve better performance under nonideal grid conditions. However, balancing fast dynamic response and good disturbance rejection capability is still difficult. Moreover, no comparative analysis of several existing typical LADRC-type SRF-PLLs has been reported yet. Therefore, the typical LADRC-type SRF-PLL structures are compared and analyzed in detail as well as control parameters tuning. In addition, a modified LADRC-type SRF-PLL with an adaptive extended state observer is proposed. It can achieve both fast dynamic response and good disturbance rejection capability. Finally, simulation and experimental results are carried out to validate the effectiveness of the proposed modified LADRC-type SRF-PLL.