LCL型单相光伏并网逆变器控制策略的研究

发布时间：2018-09-12 11:04

【摘要】：随着能源危机和环境问题的日益加剧,太阳能以其独特的优势越来越受到人们的青睐。作为新能源发电的核心技术,并网逆变技术也备受关注,积极进行光伏并网逆变器的研究和开发,将光伏电池阵列发出的直流电逆变成可以并入国家电网的高质量电能送入千家万户,才能真正的解决能源危机问题。本文的主要工作如下：研究了光伏并网逆变器拓扑结构,明确其控制目标,分析了不同单相光伏并网逆变器拓扑电路和常用并网逆变器控制技术的优缺点。针对单相非隔离型光伏并网逆变器,分析其工作原理和SPWM调制技术,完成了boost电路参数的设计,进而对比分析L、LC、LCL三种滤波器的滤波性能,选择具有谐波抑制作用的LCL型滤波器并依据其约束条件完成对其参数的设计。在DC-AC环节,针对LCL型单相光伏并网逆变器易发生谐振的问题,提出采用以并网电流为外环控制量、电容电流为内环控制量,附加输出电压跟踪调整功能的双电流环控制的控制策略,设计了双电流环控制参数并通过SISOTOOL工具对其进行整定,同时分析了坐标变换的同步锁相环控制技术,设计了基于同步旋转坐标变换的锁相环的控制参数。最后,基于MATLAB/SIMULINK软件平台搭建了基于电流双环控制的LCL单相并网逆变器的仿真模型,仿真结果表明,LCL型单相并网逆变器系统在采用双电流环控制的控制策略可有效抑制系统振荡,降低并网电流谐波含量和提高系统稳定性。保证逆变器输出电流为正弦波,输出电压与电网电压同频、同相,使单相并网逆变器工作在较高功率因数并网,验证了所设计的控制策略的可行性。
[Abstract]:With the increasing energy crisis and environmental problems, solar energy is becoming more and more popular for its unique advantages. As the core technology of new energy generation, grid-connected inverter technology is also paid close attention to, and the research and development of photovoltaic grid-connected inverter are actively carried out. In order to solve the problem of energy crisis, the direct current produced by photovoltaic cell array can be transformed into high quality electric energy that can be incorporated into the state grid and sent to thousands of households. The main work of this paper is as follows: the topology structure of photovoltaic grid-connected inverter is studied and its control target is defined. The advantages and disadvantages of different single-phase photovoltaic grid-connected inverter topology circuits and common grid-connected inverter control techniques are analyzed. Aiming at single-phase non-isolated photovoltaic grid-connected inverter, this paper analyzes its working principle and SPWM modulation technology, completes the design of boost circuit parameters, and then compares and analyzes the filtering performance of three kinds of filters. The LCL filter with harmonic suppression is selected and its parameters are designed according to its constraints. In DC-AC, aiming at the problem that LCL single-phase photovoltaic grid-connected inverter is easy to resonate, it is proposed to use grid-connected current as outer loop control quantity and capacitive current as inner loop control quantity. The control strategy of double current loop control with additional output voltage tracking and adjusting function is introduced. The control parameters of double current loop are designed and adjusted by SISOTOOL tool. At the same time, the synchronous phase-locked loop control technology based on coordinate transformation is analyzed. The control parameters of PLL based on synchronous rotation coordinate transformation are designed. Finally, based on MATLAB/SIMULINK software platform, the simulation model of LCL single-phase grid-connected inverter based on double-loop current control is built. The simulation results show that the control strategy of double-current loop control can effectively suppress the system oscillation in the single-phase grid-connected inverter system. Reduce the harmonic content of grid-connected current and improve the stability of the system. The output current of the inverter is sine wave, the output voltage is the same frequency as the grid voltage and the phase is the same. The single-phase grid-connected inverter is connected to the grid in a higher power factor. The feasibility of the proposed control strategy is verified.
【学位授予单位】：宁夏大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM464;TM615

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