Aiming at the phase lag problem existing in the differentiator of the traditional active damping control method
an active damping control strategy for LC-type off-grid inverters based on a new type of digital differentiator is proposed in this paper. In this method
a new phase compensator is designed to compensate the phase delay of the backward differential differentiator more accurately
and the forward damping interval of the system is increased. The capacitive voltage active damping feedback coefficient has a larger selection interval
and the stability of the system and the ability to suppress the resonance peak are improved. The novel differentiator proposed in this paper is closer to the frequency characteristics of the ideal differentiator
and feedback parameters can be designed based on the active damping control mode of capacitive current feedback. The feasibility and effectiveness of the proposed method are confirmed by simulation and experimental results.
XIN Z, LOH P C, WANG X F, et al.Highly accurate derivatives for LCL-filtered grid converter with capacitor voltage active damping[J]. IEEE transactions on power electronics, 2016, 31(5): 3612-3625.
PAN D H, RUAN X B, WANG X H.Direct realization of digital differentiators in discrete domain for active damping of LCL-type grid-connected inverter[J]. IEEE transactions on power electronics, 2018, 33(10): 8461-8473.
SHEN G Q, ZHU X C, ZHANG J,et al.A new feedback method for PR current control of LCL-filter-based grid-connected inverter[J]. IEEE transactions on industrial electronics, 2010, 57(6): 2033-2041.
HUANG R Z, QUAN X J, WU Z J, et al.A novel reduced-order generalized differentiator with zero-phase lag and improved noise attenuation[J]. IEEE transactions on power electronics, 2023, 38(2): 1406-1411.
ZHANG H, WANG X H, HE Y Y,et al.A compensation method to eliminate the impact of time delay on capacitor-current active damping[J]. IEEE transactions on industrial electronics, 2022, 69(7): 7512-7516.
CHEN Y, ZHANG B, QIU D Y, et al.A unified frequency-domain model of analog and digital PWM DC-DC converter considering PWM delay[J]. IEEE transactions on power electronics, 2023, 38(12): 15390-15405.
FANG T Z, SHEN S H, ZHANG L, et al.Capacitor current feedback with phase-lead compensator to eliminate resonant frequency forbidden region for LCL-type grid-connected inverter in weak grid[J]. IEEE journal of emerging and selected topics in power Electronics, 2021, 9(5): 5581-5596.