| 引用本文: | 李俊涛,贾 科,董学正,等.基于功率自反馈迭代的光伏直流并网系统交流故障有功控制[J].电力系统保护与控制,2023,51(23):37-44.[点击复制] |
| LI Juntao,JIA Ke,DONG Xuezheng,et al.Active power control strategy for a photovoltaic DC grid-connected system based on power self feedback iteration in an AC fault[J].Power System Protection and Control,2023,51(23):37-44[点击复制] |
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| 摘要: |
| 交流电网发生故障后，光伏直流并网系统须进入低电压穿越模式并降低光伏单元有功出力，以避免直流母线过压。然而，电网电压深度跌落时，光伏单元控制环路切换可能产生倒流，甚至损毁光伏阵列。为此，提出基于功率自反馈迭代的光伏直流并网系统交流故障有功控制策略。利用光伏阵列PU特性曲线构建端口电压参考值迭代算式，并根据光伏单元输出功率反馈更新该参考值。同时提出了单机尽限利用的分配方案，以合理选择参与功率控制任务的光伏单元。所提方法的优点在于无须切除光伏单元控制环路，能够可靠计算光伏阵列端口电压参考值。仿真验证表明所提方法能够有效实现系统降有功的控制目标，并减小模式切换过程中光伏单元直流变流器低压侧的电流波动量，为系统低电压穿越的可靠实现提供保障。 |
| 关键词: 光伏直流并网系统 交流故障 有功控制 迭代计算 功率自反馈 |
| DOI：10.19783/j.cnki.pspc.231007 |
| 投稿时间：2023-08-04修订日期：2023-09-24 |
| 基金项目:国家自然科学基金项目资助(52277097) |
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| Active power control strategy for a photovoltaic DC grid-connected system based on power self feedback iteration in an AC fault |
| LI Juntao,JIA Ke,DONG Xuezheng,BI Tianshu |
| (State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources
(North China Electric Power University), Beijing 102206, China) |
| Abstract: |
| After a fault occurs in the AC power grid, the photovoltaic (PV) DC grid-connected system (PV-DCGS) needs to enter the low voltage ride-through (LVRT) mode and reduce the active power of PVs to avoid DC bus overvoltage. However, when the grid voltage drop is deep, the control loop switching of the PVs can cause current backflow, and even damage to the PV panel. Therefore, this paper proposes an AC fault active power control strategy for PV-DCGS based on power self-feedback iteration. Using the PU characteristic curve of PV, an iterative formula of the port voltage reference value is constructed, and the reference value is updated according to the output power feedback of PV. At the same time, the distribution scheme of single-machine maximum utilization is proposed to rationally select the PVs that could participate in the power control task. The advantage of the proposed method is that it does not need to cut off the control loop of the PVs, and it can reliably calculate the port voltage reference value of the PVs. Simulation verification shows that the proposed method can reduce active power in the system and reduce the current fluctuation on the low-voltage side of the DC converter of PV during the PV’s mode-switching process, providing a guarantee for the reliable implementation of LVRT in the system. |
| Key words: PV-DCGS AC fault active power control iterative calculation active power self-feedback |
