变速恒频双馈风电系统最大风能追踪的研究

发布时间：2018-07-12 16:02

本文选题：风力发电 + 变速恒频　；参考：《中国矿业大学》2014年硕士论文

【摘要】：随着全球生态环境的不断恶化，能源的短缺，各个国家都在资金、政策与技术方面加大对新型绿色能源的投入。其中风能是一种发展潜力很大的新能源，近年来一直倍受青睐。目前风电系统正向着日益大型化的方向发展，其中变速恒频双馈风电系统的优势日益明显，，尤其是可在较宽的风速范围内实现输出电能的恒频恒压的特点，受到了人们的广泛关注。本文以变速恒频双馈风电系统为主要研究对象，首先深入分析了风力机与双馈发电机的基本原理和运行机理，在此基础上，运用矢量控制技术对双馈电机进行功率解耦控制，并建立了风电系统数学模型。然后以风力机捕获最大风能为控制目标，从风能利用率角度出发，重点研究最大风能追踪的控制。双馈异步发电机功率解耦控制是实现风电系统变速恒频运行的关键，如果解耦不合适，就会使系统的控制变得非常困难，严重的会使电机的电磁量发生相互干扰或震荡，使系统无法正常运行。本文在分析了双馈异步发电机基本工作原理、等效电路、功率流向的基础上，运用矢量坐标变换将三相静止坐标系下的双馈电机数学模型变换到两相同步速度旋转坐标系下，并以定子磁链为定向矢量的矢量控制对其进行功率解耦，并以此建立了风电系统整体仿真模型，通过仿真结果说明了控制方法的有效性和可行性。大型风力机组运行过程一般可分为三个阶段，即起动阶段、欠功率阶段和额定功率保持阶段，对于不同的阶段，最大风能追踪的控制策略有所不同。在启动阶段，风力机的输出功率为零，风能的利用率最小，不存在风能的追踪利用问题，一般将发电机与电网脱离；在欠功率阶段，风速在额定风速以下，风力机的输出功率一般不会超出其额定功率，也就不会存在安全性方面的问题，更多关注的是让风力机的输出功率最大化；在额定功率保持阶段，由于风速较大，更应该关心整个风电系统的安全性问题，此时一般依靠风力机变桨距控制和发电机转速控制来限制风电系统对风能的吸收。为此，本文以欠功率阶段的最大风能追踪为研究重点，对风力机捕获风能的过程进行全面的理论分析，提出基于蚁群算法自整定PID在最大风能追踪控制中的应用，具体设计了基于蚁群算法自整定PID控制器，并对其进行相应的仿真分析，仿真结果表明了该控制策略不仅使控制系统具有良好的动态响应能力，而且提高了控制精度，在风能利用率等方面也明显优于传统的PID控制方法。
[Abstract]:With the deterioration of the global ecological environment and the shortage of energy, every country has increased its investment in new green energy in terms of funds, policies and technologies. Among them, wind energy is a new energy with great development potential, and has been favored in recent years. At present, wind power system is developing towards an increasingly large scale, in which the advantages of variable speed constant frequency doubly-fed wind power system are becoming more and more obvious, especially the characteristics that the constant frequency constant voltage of electric energy output can be realized in a wide range of wind speed. Has received the widespread attention of the people. In this paper, the variable speed constant frequency doubly-fed wind power system is taken as the main research object. Firstly, the basic principle and operation mechanism of wind turbine and doubly-fed generator are deeply analyzed. On this basis, the power decoupling control of doubly-fed wind turbine is carried out by using vector control technology. The mathematical model of wind power system is established. Then the maximum wind energy capture is taken as the control target, and the control of maximum wind energy tracking is mainly studied from the point of view of wind energy utilization. The power decoupling control of doubly-fed asynchronous generator is the key to realize the variable speed constant frequency operation of wind power system. If decoupling is not suitable, the control of the system will become very difficult, and the electromagnetic quantity of the motor will be interfered or oscillated seriously. Prevents the system from working properly. Based on the analysis of basic working principle, equivalent circuit and power flow direction of doubly-fed asynchronous generator, the mathematical model of doubly-fed generator in three-phase static coordinate system is transformed into two-phase synchronous speed rotating coordinate system by vector coordinate transformation. The stator flux is used as the directional vector to decouple its power, and the overall simulation model of wind power system is established. The simulation results show the effectiveness and feasibility of the control method. The operation process of large wind turbine can be divided into three stages, that is, starting stage, underpower stage and rated power keeping stage. For different stages, the control strategy of maximum wind energy tracking is different. In the start-up phase, the output power of the wind turbine is zero, the utilization rate of the wind energy is the least, and there is no problem of tracking and utilization of the wind energy, so the generator is generally separated from the power grid; in the underpower stage, the wind speed is below the rated wind speed. Generally speaking, the output power of wind turbine does not exceed its rated power, so there will be no security problem. More attention is paid to maximizing the output power of wind turbine. In the phase of maintaining rated power, due to the large wind speed, We should pay more attention to the safety of the whole wind power system, which usually depends on the wind turbine pitch control and generator speed control to limit the wind energy absorption. Therefore, this paper focuses on the maximum wind energy tracking in underpower stage, makes a comprehensive theoretical analysis on the wind energy capture process of wind turbine, and puts forward the application of self-tuning pid based on ant colony algorithm in the maximum wind energy tracking control. A self-tuning pid controller based on ant colony algorithm is designed and simulated. The simulation results show that the control strategy not only makes the control system have a good dynamic response ability, but also improves the control accuracy. It is also superior to the traditional pid control method in wind energy utilization rate and so on.
【学位授予单位】：中国矿业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM614

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