直驱式风力发电并网变流器设计及其控制策略研究

【作者】 郭建军；

【导师】 阳春华； 段仁君；

【作者基本信息】 中南大学 ， 控制工程， 2009， 硕士

【摘要】 随着石油、天然气、煤炭等传统化石燃料的枯竭和及其燃烧对环境造成的严重污染,作为可再生绿色能源的风能的开发利用具有十分重要的意义。现存的大功率并网型风力发电机组大多采用包含提速齿轮箱的定速恒频的运行方式,存在运行效率低、噪音和机械损耗大等缺点。直驱型风电机组因其具有能量转换效率高、可靠性高、并网功率控制灵活等优点,成为了继双馈型风电机组之后风力发电技术领域的重要研究方向。然而,对于目前主流的兆瓦级直驱型风电机组而言,我国在变流机组及其核心控制技术方面仍依赖进口,极大制约了风电产业的进一步发展。因此,本文围绕直驱型风力发电并网变流器及其控制策略展开研究。论文首先概述了风电发展现状,比较了当前两种主流技术：双馈式发电机风电系统与直驱式多极同步电机变流器风力发电系统。在简要介绍系统的结构特点与控制要求之后,论文重点研究了并网PWM变流器,阐述了其工作原理和特点。为了进一步研究控制策略,对控制对象进行了数学建模。针对主电路数学模型,研究了基于预测电流(PCFF)的并网PWM变流器控制策略。先通过坐标变换与小信号线性化处理得到系统的连续时不变线性方程,再据此求得传递函数阵并对系统进行了稳态分析。论文还研究了直流电压控制与针对中点接地系统的电压补偿环节,对实际大功率系统做了MatLab仿真以验证控制方法的有效性及参数设计的正确性。在理论分析与仿真的基础上,本文对提出的控制策略进行了实验研究,设计了实验控制系统的硬件电路和DSP程序。实验结果与理论分析吻合,表明应用该控制策略的PWM变流器具有较好的稳态与动态性能,适用于大功率风力发电应用场合。更多还原

【Abstract】 With the shortage of the fossil fuel such as coal, oil and the environment pollution caused by the combustion of fossil fuel, It is of great significance to develop and utilize wind power, which is not only renewable but also without pollution.At the same time,the most of high-power grid-connected wind turbine works as constant speed and constant frequency(CSCF)including up-speed gear.It has low efficiency,makes mechanism spoilage and much noises.Direct-driven wind generation system is considered to be an important research direction in wind generation teehnology area due to its superiorities of being gearless,no slip rings and brushes,flexible power controllability,etc. However,as to MW direct-driven wind turbine, the power converter and core control technologies are still relied on importing in our country, which signifieantly restriets further development of wind energy industry. Therefore, this dissertation gives study on grid-connected power conversion and control strategies for direct-driven wind generation system.Following introduction of the topology characteristics and control requirements of the system, the grid-side converter is emphasized.The mathematical models at low and high frequency is given for general circuits.For models of the main circuits, predicted current control (PCFF) strategies are discussed subsequently, according to which the steady-state solutions and transfer function matrix could be calculated.Moreover the general dc voltage controller and particular compensator for the system with neutral line are also designed.The simulation verification is made using MatLab for the large-scale system.Predicted current control (PCFF) for the PWM converter are testified experimentally, following designing the hardware circuits and DSP programmes of the control system. The results and analysis for steady-state waveforms, dynamic performances and harmonic cancellation of duplication are provided demonstrating the feasibility in wind power generation and validating the theory presented before.更多还原