| 引用本文: | 杨明,宋静文,刘子坤,等.弱电网下基于频率自适应的新型锁相环设计方法及其稳定性分析[J].电力系统保护与控制,2026,54(10):47-58. |
| YANG Ming,SONG Jingwen,LIU Zikun,et al.Design and stability analysis of a new frequency-adaptive phase-locked loop for weak grids[J].Power System Protection and Control,2026,54(10):47-58 |
|
| 摘要: |
| 针对弱电网下锁相环与电网阻抗相互耦合而导致系统稳定性下降的问题，从优化锁相环控制结构的角度出发，提出一种具有频率自适应性的新型锁相环设计方法。首先，建立考虑锁相环影响的系统输出导纳模型，对传统锁相环 (phase-locked loop, PLL) 和解耦锁相环 (decoupled phase-locked loop, DPLL) 在弱电网下的稳定性与动态性能进行分析，可得传统 PLL 与 DPLL 在电网阻抗增大以及电网波动时均表现出稳定性下降与动态响应变差的特征。然后，在 DPLL 基础上引入惯性环节与外环频率跟踪单元，构建一种具有频率自适应的新型锁相环 (new phase-locked loop, NPLL) 结构，通过增强系统阻尼与实时频率追踪能力来优化控制性能。最后，仿真与实验结果表明，所提方案不仅显著拓宽了电网阻抗的适应范围，而且在电网波动的工况下表现出优于传统 PLL 与 DPLL 的频率跟踪能力与动态响应，有效提升了系统的鲁棒性与并网电能质量。 |
| 关键词: 弱电网 锁相环 并网逆变器 频率自适应 系统稳定性 |
| DOI：10.19783/j.cnki.pspc.251267 |
| 分类号: |
| 基金项目:国家自然科学基金项目资助 (U1804143)；河南省科技攻关项目资助 (252102241061) |
|
| Design and stability analysis of a new frequency-adaptive phase-locked loop for weak grids |
|
YANG Ming, SONG Jingwen, LIU Zikun, XIAO Di
|
|
Henan Key Laboratory of Intelligent Detection and Control of Coal Mine Equipment (School of Electrical Engineering and Automation, Henan Polytechnic University), Jiaozuo 454003, China
|
| Abstract: |
| To address the issue of decreased system stability caused by the coupling between the phase-locked loop (PLL) and grid impedance in weak grids, a novel frequency-adaptive PLL design method is proposed from the perspective of optimizing the control structure. First, a system output admittance model considering the influence of the PLL is established. Based on this model, the stability and dynamic performance of the conventional PLL and the decoupled phase-locked loop (DPLL) under weak grid conditions are analyzed. The results show that both PLL and DPLL exhibit reduced stability and degraded dynamic response as grid impedance increases or grid fluctuations intensify. Then, based on the DPLL, an inertial element and an outer-loop frequency tracking unit are introduced to construct a new frequency-adaptive phase-locked loop (NPLL) structure with frequency adaptability. By enhancing system damping and real-time frequency tracking capability, the proposed method improves overall control performance. Finally, simulation and experimental results demonstrate that the proposed scheme significantly expands the range of grid impedance adaptability and exhibits superior frequency tracking capability and dynamic response under grid fluctuation conditions compared to traditional PLL and DPLL, thereby effectively improving system robustness and grid-connected power quality. |
| Key words: weak grid phase-locked loop grid-connected inverter frequency adaptability system stability |
