LCL型并网逆变器控制系统的研究

发布时间：2018-05-30 08:08

本文选题：并网逆变器 + 双极性SPWM　；参考：《江苏大学》2017年硕士论文

【摘要】：当今世界,随着一次常规能源的枯竭和全球环境污染的加剧,太阳能、风能等可再生能源的开发与利用成为人们解决当今能源危机的关键突破口。新能源并网发电是可再生能源利用的主要形式,而并网逆变器是新能源与电网连接的中间桥梁,它的主要功能是将新能源产生的电能转换为符合电网标准的交流电能。本文采用LCL型并网逆变器并网电流和电容电流双闭环控制的拓扑结构,选用高阶LCL滤波器滤除并网逆变器桥臂输出电压中大量的高频谐波;引入电容电流反馈有源阻尼的方法来抑制LCL滤波器的固有谐振尖峰,保证并网逆变器系统稳定工作;利用可视化算法对调节器PI参数进行分析与推导,为LCL型并网逆变器系统电流调节器PI的设计提供理论基础和依据。本文的研究工作具体如下:首先,建立LCL型并网逆变器系统的电路拓扑结构,分析双极性SPWM脉宽调制的原理,论证单相与三相并网系统在电路结构和原理上的相通性,为单相和三相并网逆变器系统的统一设计提供理论基础。根据并网逆变器系统运行的技术指标,设计LCL滤波器的参数。其次,对LCL型并网逆变器双闭环控制系统进行数学建模与分析,推导并网逆变器系统的双闭环传递函数。利用Matlab分析并网逆变器系统的Bode图,验证电容电流反馈有源阻尼对电流双闭环控制系统幅频谐振尖峰的抑制效果。通过可视化算法对并网电流调节器PI的参数进行设计,利用频域和时域性能指标的要求,整定调节器PI的可视化参数域。该方法可得到最优的PI参数域,无需重复试凑。再次,介绍LCL型三相并网逆变器系统的三种并网电流控制方式,采用并网电流dq控制方式进行仿真研究。利用Matlab/Simulink搭建LCL型单相和三相电流并网逆变器系统仿真平台,选取调节器PI的最优参数域进行仿真,分析系统输出波形的谐波含量、满载与半载的动静态性能等,理论上验证并网逆变器双闭环控制系统设计的合理性和可行性。最后,设计了基于DSP-TMS320F2812的硬件系统和HDSP-XDS510USB的软件系统,搭建了LCL型单相3kW和三相9kW的并网逆变器原理实验样机。实验的波形与数据验证了上述理论分析的正确性和可视化算法参数设计的有效性。
[Abstract]:In today's world, with the depletion of primary conventional energy and the aggravation of global environmental pollution, the development and utilization of renewable energy, such as solar energy and wind energy, has become a key breakthrough for people to solve today's energy crisis. Grid-connected power generation is the main form of renewable energy utilization, and grid-connected inverter is the intermediate bridge between new energy and power grid. Its main function is to convert the electric energy generated by new energy into AC energy in accordance with the grid standard. In this paper, the topology of LCL grid-connected inverter with double closed-loop control of grid-connected current and capacitive current is adopted, and high-order LCL filter is used to filter a large number of high-frequency harmonics from the output voltage of grid-connected inverter. The method of capacitive current feedback active damping is introduced to suppress the inherent resonance spike of LCL filter to ensure the stable operation of grid-connected inverter system, and the Pi parameters of regulator are analyzed and deduced by visual algorithm. It provides a theoretical basis and basis for the design of Pi current regulator in LCL grid-connected inverter system. The research work of this paper is as follows: firstly, the circuit topology of LCL grid-connected inverter system is established, the principle of bipolar SPWM pulse width modulation is analyzed, and the circuit structure and principle of single-phase and three-phase grid-connected system are proved. It provides a theoretical basis for the unified design of single-phase and three-phase grid-connected inverter systems. According to the technical specifications of grid-connected inverter system, the parameters of LCL filter are designed. Secondly, the mathematical modeling and analysis of double closed loop control system of LCL grid-connected inverter are carried out, and the double closed-loop transfer function of grid-connected inverter system is deduced. The Bode diagram of grid-connected inverter system is analyzed by Matlab to verify the suppression effect of capacitive current feedback active damping on amplitude frequency resonance peak of current double closed loop control system. The parameters of Pi of grid-connected current regulator are designed by visual algorithm, and the visual parameter domain of Pi is set according to the requirement of performance index in frequency domain and time domain. The optimal Pi parameter domain can be obtained by this method without repeated trial. Thirdly, three grid-connected current control modes of LCL type three-phase grid-connected inverter system are introduced, and the simulation research is carried out by using grid-connected current dq control mode. The simulation platform of LCL single-phase and three-phase current grid-connected inverter is built by using Matlab/Simulink. The optimal parameter domain of Pi regulator is selected to simulate, and the harmonic content of the output waveform of the system and the static and static performance of the full load and half load are analyzed. The rationality and feasibility of the design of double closed loop control system for grid-connected inverter are verified theoretically. Finally, the hardware system based on DSP-TMS320F2812 and the software system of HDSP-XDS510USB are designed, and the experimental prototype of grid-connected inverter based on LCL single-phase 3kW and three-phase 9kW is built. The experimental waveforms and data verify the correctness of the theoretical analysis and the effectiveness of the visual algorithm parameter design.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM464

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