摘要
随着可再生能源发电技术的迅速发展，并网逆变器作为连接电网与分布式发电系统的关键设备，其性能优劣直接影响到整个并网系统的稳定性和电能质量。然而，在实际运行中，电网电压往往受到多种非理想因素的影响，如不平衡、谐波畸变等，这些非理想条件对并网逆变器的输出性能构成了严峻挑战。本文深入研究了电网电压非理想条件下逆变器并网控制策略。首先，针对电网电压的不平衡和谐波畸变问题，本文建立了LCL滤波三相并网逆变器的数学模型，并考虑了数字控制中可能产生的延时效应。通过对不同数字SPWM调制方法的分析，揭示了数字延时对系统性能的影响机理。在此基础上，本文设计了优化的电流调节器和LCL滤波器参数，旨在提高并网逆变器在电网电压非理想条件下的控制性能，并降低数字延时对系统稳定性的影响。本文提出了一种改进的控制策略，该策略通过综合应用预测占空比、零极点补偿控制以及正负序分量复数滤波器等技术，有效提升了并网逆变器的动态性能，并成功抑制了电网电压谐波引起的并网电流畸变。此外，本文还推导出了使系统稳定的内环电容电流反馈系数的取值域，并通过仿真验证了所提控制策略的有效性和优越性。
关键词：电网电压非理想条件；并网逆变器；控制策略
Abstract
With the rapid development of renewable energy power generation technology, the grid-connected inverter is as a key equipment connecting the power grid and the distributed power generation system. Its performance directly affects the stability and power quality of the whole grid-connected system. However, in the actual operation, the power grid voltage is often affected by many non-ideal factors, such as imbalance, harmonic distortion, etc., and these non-ideal conditions pose a severe challenge to the output performance of the grid-connected inverter. This paper studies the inverter grid connection control strategy under grid voltage non-ideal conditions. Firstly, for the imbalance of grid voltage and harmonic distortion, we establish the mathematical model of LCL filter three-phase grid-connected inverter and consider the possible delay effect in digital control. The analysis of different digital SPWM modulation methods reveals the mechanism of digital delay on system performance. On this basis, this paper designs the optimized current regulator and LCL filter parameters, aiming to improve the control performance of grid-connected inverter under the power grid voltage and reduce the influence of digital delay on system stability. In this paper, an improved control strategy is proposed, which effectively improves the dynamic performance of the grid-connected inverter by comprehensively applying the predicted duty cycle, zero pole compensation control and the complex filter of positive and negative order components, and successfully suppresses the grid-connected current distortion caused by the grid voltage harmonics. Furthermore, the value domain of the feedback coefficient of the internal loop capacitance current stabilizes the system, and then the effectiveness and superiority of the proposed control strategy are verified through simulation.
Keywords：Power grid voltage is not ideal condition; grid-connected inverter; control strategy
目 录
摘要 I
Abstract II
一、绪论 1
（一）研究背景及意义 1
（二）研究目的和内容 1
（三）国内外研究现状 1
二、电网电压非理想条件概述 3
（一）电网电压非理想条件定义 3
（二）电网电压非理想条件的特点 3
（三）电网电压非理想条件的检测与识别 3
三、逆变器并网控制策略相关概述 5
（一）控制策略的分类 5
（二）控制策略的基本原理 5
（三）逆变器并网控制策略的数学模型 6
四、先进控制技术在逆变器并网中的应用 7
（一）预测控制技术在逆变器并网中的应用 7
（二）自适应控制技术在逆变器并网中的应用 7
（三）人工智能技术在逆变器并网中的应用 7
（四）最大功率点跟踪技术在逆变器并网中的应用 8
五、电网电压非理想条件下的逆变器并网控制策略 9
（一）电网电压非理想条件下的逆变器并网控制策略 9
（二）预测占空比与零极点补偿控制 9
（三）正负序分量提取与处理 10
（四）电流与功率协同控制 10
结 论 11
参考文献 12
