摘要
LCL型并网逆变器采用网压比例前馈策略可以有效地抑制电网背景谐波,但在弱电网下,随着电网阻抗的增大,系统逐渐失稳,同时再考虑锁相环影响,系统鲁棒性大幅降低。为此,本文首先建立包含锁相环以及网压比例前馈的LCL型并网逆变器阻抗模型,并采用阻抗分析法进行稳定性分析;提出了在锁相环以及网压前馈通道前串联陷波器对逆变器等效输出阻抗相位进行补偿的改进策略,在提升系统鲁棒性的同时保留网压比例前馈策略谐波抑制能力。然而,改进策略无法满足电网阻抗宽范围变化时系统稳定的要求,因此在改进策略的基础上加入了自适应环节,通过电网阻抗测量技术结合粒子群优化算法对陷波器参数进行自适应优化,从而提升系统在电网阻抗宽范围变化时的鲁棒性。最终通过仿真与实验验证了自适应改进策略的正确性和有效性。
LCL grid-connected inverter can effectively suppress grid background harmonics by adopting the traditional proportional feed-forward strategy,but under the weak grid,with the increase of grid impedance,the system gradually becomes unstable,and at the same time as regarding to the effect of phase-locked loop,the robustness of the system is greatly reduced.To this end,first the LCL parallel inverter impedance model is established,which contains the phase-locked loop and the network voltage scale feed-forward strategy,and the impedance analysis method is used for stability analysis.An improved strategy for compensating the inverter equivalent output impedance phase with a series of in-line notches before the phase-locked loop and the mesh feed-forward channel is proposed,which improves the robustness of the system while retaining the harmonic suppression capability of the traditional proportional feed-forward strategy.However,the improvement strategy can not meet the stability demand of the system when the grid impedance range changes widely,so on the basis of the improvement strategy an adaptive link is added through the grid impedance measurement technology combined with the particle group optimization algorithm to adapt to optimizaiton of the trap parameters,so as to improve the system’s adaptability to the wide change of grid impedance.Finally,the correctness and effectiveness of adaptive improvement strategies are verified by simulation.
作者
赵铁英
高宁
杨杰
杨明
李俊然
ZHAO Tieying;GAO Ning;YANG Jie;YANG Ming;LI Junran(School of Electrical Engineering and Automation,Henan Polytechnic University,Jiaozuo 454003,China)
出处
《电工电能新技术》
CSCD
北大核心
2023年第4期29-38,共10页
Advanced Technology of Electrical Engineering and Energy
基金
国家自然科学基金项目(U1804143)
河南理工大学博士基金项目(B2014-027)。
关键词
弱电网
并网逆变器
改进前馈
锁相环
自适应
粒子群优化算法
weak grid
grid-connected inverter
novel feed-forward
phase-locked loop
adaptability
particle swarm optimization
