弱电网下光伏并网逆变器的稳定性研究
发布时间：2018-08-03 12:10
【摘要】：随着能源问题日益突出,发展新能源分布式发电成为解决人类可持续发展的必由之路,并网逆变器作为新能源实现并网发电的关键设备也越来越受到人们的重视。小容量的电力系统经过高压输配电网络几级变压和长距离输电寄生了大量电网阻抗使之呈现弱电网特性。受弱电网变化电网阻抗的影响,逆变器存在稳定性下降甚至失去稳定的风险。本文首先从频域角度分析了弱电网下电网阻抗和并网点本地负载对并网逆变器的交互影响,得出了电网寄生电感是导致系统稳定性下降的主要原因。在此基础上明确了基于电网阻抗在线测量自适应控制的基本思路,详细分析了现有基于传统傅里叶变换电网阻抗测量算法存在的问题,并对此提出了基于加窗傅里叶变换阻抗测量的新算法。其次分析了弱电网条件下电网阻抗的补偿策略及其对系统被控对象频率特性的影响,基于此提出系统PI和PR电流控制器参数整定方法及步骤。对比分析了PI与PR控制器在弱电网性能的优劣,提出了基于PR控制器的自适应控制策略。对自适应控制算法进行了简化并推导了控制器差分方程以便于数字控制器运行。再次详细介绍了基于TMS320F28335单相光伏并网实验平台的结构组成及软硬件设计与实现。最后通过Matlab/Simulink软件仿真和实验验证了本文主要的理论分析的正确性和所提算法的有效性。
[Abstract]:With the increasingly prominent energy problem, the development of new energy distributed generation has become the only way to solve the sustainable development of human beings. Grid-connected inverter, as the key equipment to realize grid-connected power generation, has been paid more and more attention. Small capacity power systems exhibit weak network characteristics through several stages of high voltage transmission and distribution networks and long distance transmission parasitic on a large number of network impedance. Under the influence of the grid impedance of the weak grid, the inverter has the risk of stability decline or even loss of stability. In this paper, the interaction of impedance and local load on grid-connected inverter is analyzed in frequency domain, and the parasitic inductance of power grid is the main reason that leads to the decline of system stability. On this basis, the basic idea of adaptive control based on on-line measurement of power network impedance is clarified, and the problems existing in the existing impedance measurement algorithms based on traditional Fourier transform are analyzed in detail. A new algorithm for impedance measurement based on windowed Fourier transform is proposed. Secondly, the compensation strategy of power network impedance and its influence on the frequency characteristics of the controlled system are analyzed. Based on this, a parameter tuning method and steps for Pi and PR current controllers are proposed. The performance of Pi and PR controllers in weak network is compared and analyzed, and an adaptive control strategy based on PR controller is proposed. The adaptive control algorithm is simplified and the differential equation of the controller is derived to facilitate the operation of the digital controller. The structure, hardware and software design and implementation of single phase photovoltaic grid-connected experimental platform based on TMS320F28335 are introduced in detail. Finally, the correctness of the main theoretical analysis and the validity of the proposed algorithm are verified by the simulation and experiment of Matlab/Simulink software.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464;TM615
[Abstract]:With the increasingly prominent energy problem, the development of new energy distributed generation has become the only way to solve the sustainable development of human beings. Grid-connected inverter, as the key equipment to realize grid-connected power generation, has been paid more and more attention. Small capacity power systems exhibit weak network characteristics through several stages of high voltage transmission and distribution networks and long distance transmission parasitic on a large number of network impedance. Under the influence of the grid impedance of the weak grid, the inverter has the risk of stability decline or even loss of stability. In this paper, the interaction of impedance and local load on grid-connected inverter is analyzed in frequency domain, and the parasitic inductance of power grid is the main reason that leads to the decline of system stability. On this basis, the basic idea of adaptive control based on on-line measurement of power network impedance is clarified, and the problems existing in the existing impedance measurement algorithms based on traditional Fourier transform are analyzed in detail. A new algorithm for impedance measurement based on windowed Fourier transform is proposed. Secondly, the compensation strategy of power network impedance and its influence on the frequency characteristics of the controlled system are analyzed. Based on this, a parameter tuning method and steps for Pi and PR current controllers are proposed. The performance of Pi and PR controllers in weak network is compared and analyzed, and an adaptive control strategy based on PR controller is proposed. The adaptive control algorithm is simplified and the differential equation of the controller is derived to facilitate the operation of the digital controller. The structure, hardware and software design and implementation of single phase photovoltaic grid-connected experimental platform based on TMS320F28335 are introduced in detail. Finally, the correctness of the main theoretical analysis and the validity of the proposed algorithm are verified by the simulation and experiment of Matlab/Simulink software.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464;TM615
【参考文献】
相关期刊论文 前10条
1 付勋波;段江曼;赵栋利;许洪华;;逆变器并联谐振及多重抑制方法研究[J];可再生能源;2017年01期
2 张e，
本文编号：2161705
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