直驱电励磁风电机组的直流侧电压波动抑制及低电压穿越控制

发布时间：2018-02-14 09:25

本文关键词： 风力发电直驱电励磁直流侧电压电网故障低电压穿越　出处：《重庆大学》2015年硕士论文　论文类型：学位论文

【摘要】：当今世界能源安全问题日益突出,生态环境恶化日趋严重,风力发电作为一种相对成熟的清洁型可再生能源受到越来越重视,是解决能源问题的一种有效途径。在各种风力发电机组中,直驱电励磁同步风电机组由于其传动系统简单、避免采用昂贵的永磁材料、励磁可调、发电效率高、运行可靠性好等优点而受到广泛关注。因此,本文以直驱电励磁同步风电机组为研究对象,深入研究了抑制直流侧电压波动的控制策略,并对电网故障情况下机组的低电压穿越进行了探讨,主要内容概括如下:①本文根据直驱电励磁同步风电机组并网结构特点,重点介绍了风力机、传动系统、电励磁同步电机、整流逆变环节等几个主要模块的工作原理和数学模型,为后续研究奠定了基础。②提出了新型直流侧电压波动抑制策略。当风速突变时,采用传统双闭环控制策略的网侧变流器不会及时改变并网输出有功功率,直流侧电压出现大幅度波动,这将不利于电力电子器件和整个风电机组的稳定运行。因此本文在分析直流侧电压波动产生机制的基础上,针对直驱电励磁风电机组提出了考虑直流电压偏差信息的直流电压波动抑制策略。在风速突变时,基于最大风能跟踪控制的网侧变流器在直流电压偏差信息的补偿作用下及时改变并网输出有功功率,稳定直流侧电压。仿真分析表明,本文所提控制策略在风速突变时能够有效抑制直流电压波动。③设计了基于风电机组惯性储能的低电压穿越控制策略。为了提高基于不可控整流器-可控逆变器并网的直驱电励磁风电机组低电压穿越能力,详细分析了基于直流侧卸荷电路的常规低电压穿越控制策略的不足,进而设计了基于风电机组惯性储能的低电压穿越控制策略。在电网故障期间,该控制策略限制发电机电磁功率,使得大部分不平衡功率由发电机转子承担;并根据电网电压跌落深度,网侧变流器给电网提供一定的无功功率,支持电网恢复。以两种不同深度的电网电压跌落故障为例,对本文所提控制策略和基于卸荷电路的常规低电压穿越方法进行仿真对比,仿真结果表明,本文所提控制策略能使机组在电网故障下的运行性能得到有效改善。
[Abstract]:Nowadays, the problem of energy security in the world is becoming more and more prominent, and the ecological environment is getting worse and worse. Wind power, as a relatively mature clean renewable energy, has been paid more and more attention. It is an effective way to solve the problem of energy. Among all kinds of wind turbines, direct-drive synchronous wind turbines avoid expensive permanent magnetic materials, adjustable excitation and high generation efficiency because of their simple transmission system. Therefore, the direct drive synchronous wind turbine is taken as the research object, and the control strategy to restrain the DC side voltage fluctuation is deeply studied in this paper. The main contents are summarized as follows: 1 according to the characteristics of direct-drive excitation synchronous wind turbine grid-connected structure, this paper mainly introduces wind turbine, transmission system, electric excitation synchronous motor. The working principle and mathematical model of several main modules, such as rectifier inverter, have laid a foundation for further research. 2. A novel DC side voltage fluctuation suppression strategy is proposed. The grid-side converter with traditional double-closed-loop control strategy will not change the active power of grid-connected power in time, and the DC side voltage will fluctuate greatly. This will be unfavorable to the stable operation of the power electronic devices and the whole wind turbine. Therefore, based on the analysis of the generation mechanism of DC side voltage fluctuation, In this paper, a DC voltage fluctuation suppression strategy considering DC voltage deviation information is proposed for direct-drive excited wind turbine. Under the compensation of DC voltage deviation information, the grid-side converter based on maximum wind energy tracking control can change the active power and stabilize the DC side voltage in time. The control strategy proposed in this paper can restrain DC voltage fluctuation effectively when wind speed changes. 3. A low voltage traversing control strategy based on wind turbine inertial energy storage is designed. The low voltage traversing ability of direct-drive excitation wind turbine in the grid, The deficiency of conventional low-voltage traversing control strategy based on DC side unloading circuit is analyzed in detail, and then a low-voltage traversing control strategy based on wind turbine inertia energy storage is designed. The control strategy limits the electromagnetic power of the generator, making most of the unbalanced power borne by the generator rotor, and according to the voltage drop depth of the power grid, the grid-side converter provides a certain reactive power to the power grid. The control strategy proposed in this paper is compared with the conventional low-voltage traversing method based on unloading circuit. The simulation results show that, The control strategy proposed in this paper can effectively improve the operation performance of generating units under power network failure.
【学位授予单位】：重庆大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TM315

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