分布式发电系统中多逆变器并联并网控制技术研究

The study of multiple parallel-connected inverters is very important for the renewable-energy- based distributed power generation systems. With studies of the stability and multi-resonance problem of multiple parallel-connected inverters, which will provide the important theoretical fundamental of the development of the distributed power generation systems, it is possible to eliminate the negative effects, improve the injected power quality and guarantee the safe running multiple parallel-connected inverters. This project will study the stability and multi-resonance problem of multiple parallel-connected inverters, build the small-signal model of the multiple parallel-connected inverters, and analyze the cause of the system instability while defining the stability criterion of the system. This project will also build the circuit model of the multiple parallel-connected inverters, reveal the mechanism of the multi-resonance, and categorize the cause of multi-resonance. Besides, the interconnection between the stability and multi-resonance cause is also studied in this project, and the methods of stabilizing the system while suppressing the multi-resonance are proposed. Based on the aforementioned studies, the control strategies of improving the injected power quality are proposed. Considering the grid impedance and the number of parallel-connected inverters are not constant, the adaptive tuning schemes will be studied. With the study of this project, the safe, economic, efficient and high-quality operation of the multiple parallel-connected inverters can be ensured.

多逆变器并联并网技术是基于可再生能源的分布式发电系统中一项重要研究内容。研究多逆变器并联并网系统稳定性和多谐振问题，消除它们对电网的负面影响，改善并网电能质量，确保多逆变器并联并网系统可靠运行，将为分布式发电技术的发展提供重要的理论基础。本项目将针对多逆变器并联并网系统的稳定性和多谐振问题开展研究，建立多逆变器并联并网系统小信号模型，分析影响系统稳定性的原因，指出实现稳定的条件；建立多逆变器并联并网系统的电路模型，揭示引起多谐振的机理，对引起多谐振原因进行分类；研究稳定性原因和引起多谐振原因的内在联系，提出既可以实现稳定，又可以抑制多谐振的调节思路及其实现方法，在此基础上，提出提高并网电能质量的控制策略；针对电网阻抗和逆变器并联台数会发生变化，研究实现方法的自适应调节功能。通过上述研究，实现多逆变器并联并网系统安全、经济、高效、优质的并网运行。

多逆变器并联并网技术是基于可再生能源的分布式发电系统中一项重要研究内容。研究多逆变器并联并网系统稳定性和多谐振问题，消除它们对电网的负面影响，改善并网电能质量，确保多逆变器并联并网系统可靠运行，将为分布式发电技术的发展提供重要的理论基础。本项目将针对多逆变器并联并网系统的稳定性和多谐振问题开展研究，建立多逆变器并联并网系统小信号模型，分析影响系统稳定性的原因，指出实现稳定的条件；建立多逆变器并联并网系统的电路模型，揭示引起多谐振的机理，对引起多谐振原因进行分类；研究稳定性原因和引起多谐振原因的内在联系，提出既可以实现稳定，又可以抑制多谐振的调节思路及其实现方法，在此基础上，提出提高并网电能质量的控制策略；针对电网阻抗和逆变器并联台数会发生变化，研究实现方法的自适应调节功能。通过上述研究，实现多逆变器并联并网系统安全、经济、高效、优质的并网运行。