摘要
为了解决传统电容电流反馈有源阻尼(capacitor-current feedback active damping,CCFAD)控制策略有效阻尼区间不足的问题,提出了一种基于负一阶低通滤波器(negative first-order low-pass filter,NFOLPF)的改进CCFAD策略。主要针对数字控制的LCL型并网逆变器进行研究,传统CCFAD仅能保证在小于f_(s)/6的频段内的系统稳定。但是在弱电网中,电网阻抗的变化会导致谐振频率f_(r)发生偏移,若谐振发生在大于f_(s)/6的频段内,鲁棒性将会变差。改进CCFAD通过在传统有源阻尼反馈支路中加入NFOLPF,补偿延迟引入的相位滞后,扩大系统稳定域。通过理论分析可得,所提控制策略可以将有效阻尼区间扩展到f_(R),其中f_(R)∈(f_(s)/3,f_(s)/2)。同时,给出了NFOLPF系数与最大有效阻尼区以及电网强度之间的关系。仿真分析及实验结果表明,与已有补偿策略相比,所提控制策略可以扩大有效阻尼区,改善弱电网下系统稳定性。
In order to solve the problem of narrow valid damping region in the traditional capacitive-current feedback active damping(CCFAD)control strategy,we propose an improved CCFAD strategy based on negative first-order low-pass filter.The traditional CCFAD can only guarantee the stability of the LCL inverter system in the frequency smaller than f_(s)/6.When connecting into weak grids,the change of the grid impedance will lead to resonance shift.If the f_(r) is greater than f_(s)/6,the robustness will be greatly deteriorated.The advanced CCFAD strategy can compensate the phase lag caused by delay and expand the system stability range by introducing the NFOLPF into the capacitor-current feedback branch.By analyzing the active damping characteristics,the effective damping region can be extended to f_(R),where f_(R)∈(f_(s)/3,f_(s)/2).Meanwhile,the relationship between the coefficient of the NFOLPF and the maximum damping range and L_(g) is given.Simulation analysis and experimental results show that the control strategy proposed in this paper can expand the effective damping range and improve the system stability in weak grid compared with the existing compensation strategy.
作者
刘鸿鹏
边新新
张伟
曹云峰
陈继开
LIU Hongpeng;BIAN Xinxin;ZHANG Wei;CAO Yunfeng;CHEN Jikai(Key Laboratory of Modem Power System Simulation and Control&Renewable Energy Technology,Ministry of Education,Northeast Electric Power University,Jilin 132012,China;Marketing Service Center(Measurement Center,Capital Intensive Center)of State Grid Xinjiang Electric Power Co.,Ltd.,Urumqi 830000,China)
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2022年第1期114-124,共11页
High Voltage Engineering
基金
国家自然科学基金(52077030)。
