离网小型风力发电控制系统

发布时间：2018-04-26 13:15

本文选题：风力发电 + 离网　；参考：《山东建筑大学》2014年硕士论文

【摘要】：离网风力发电使用灵活、初投资小、清洁安全,适合解决边远地区的生产生活用电难题。此外,在我国内陆地区也有着丰富的风能资源,发展离网风电,对促进生态建设,改善用能结构,有着积极意义。目前,离网风力发电亟待解决的两个问题：一是研究高效的最大风能捕获控制技术,以提高风能利用,进一步降低风电成本；二是减少输出电压波动,提高用户电能质量。为此,本文设计了一种独立运行的离网风力发电控制系统：一方面改进了一种最大风能捕获控制方法,提高风能利用；另一方面,给出了一种能量协调控制策略,实现系统能量供需平衡,从而减少了输出电压波动。第一,在分析离网风力发电数学模型基础上,推导出一种不测转速的控制结构。结合模糊控制对非线性系统的良好适应能力以及PI控制的稳定、快速优点,设计了一种模糊、PI实现的爬山搜索算法。该算法利用模糊逻辑来确定参考搜索步长,再由PI调节电压闭环,跟踪参考搜索步长,实现快速、有效的最大风能捕获控制。利用Lyapnov理论,分析了该方法的稳定性。在Simulink平台上,对比分析了经典爬山算法和改进方法。结果表明,改进算法搜索效率提高了约30%。第二,设计了一种能量协调控制方法,该方法统一协调风力发电机、储能、卸荷以及负载,实现了能量供需平衡,稳定了输出电压。通过分析造成输出电压波动的原因,得出稳定直流母线电压,即可实现系统能量平衡。风力发电机依据负载需求、储能系统状态,在最大功率追踪、恒定功率以及遇限切除三种模式间切换。设计了由超级电容、蓄电池构成的储能形式。由蓄电池来缓冲低频波动,超级电容缓冲高频波动。采用这种方式,不仅提高了能量利用效率,还减少了蓄电池充放电次数,延长了蓄电池使用寿命。第三,详细阐述了离网风力发电系统硬件电路设计过程,包括设计思路、原理说明以及参数选择。硬件部分主要包括主电路、检测电路、市电切入以及LED照明负载。主电路将波动的风能转换为负载可利用的电能。检测电路,将电压、电流等模拟量转换为数字量,供DSP计算使用。在有市电接入或者柴油发电条件下,当风电、蓄电池供电不足时,设计的市电切入将自动接入市电或柴油发电,确保负载稳定工作。本文以LED照明作为负载,设计了一种高效、低温升的人体探测LED驱动电路。第四,以德州仪器生产的DSP芯片TMS320F2808为控制核心,将本文控制策略数字化实现。在软件编制过程中,应用了模块化设计理念。首先将控制功能分区,功能相同的单元作为一个模块。其次,按照模块功能编制相关软件。最后,设计了一种非抢占式多任务调度方式,对各功能模块进行调度。第五,分析了在系统调试过程中遇到的问题及解决办法。对总体软件、硬件进行了测试,测量结果验证了设计方案的可行性。
[Abstract]:Off-grid wind power generation is flexible in use, small in initial investment, clean and safe, suitable for solving the problem of power consumption in remote areas. In addition, there are abundant wind energy resources in inland areas of China. It is of positive significance to develop off-grid wind power to promote ecological construction and improve energy use structure. At present, there are two urgent problems to be solved for off-grid wind power generation: one is to study the efficient maximum wind energy capture control technology to improve wind power utilization and further reduce the cost of wind power; the other is to reduce the fluctuation of output voltage and improve the power quality of users. In this paper, an independent off-grid wind power generation control system is designed. On the one hand, a maximum wind energy capture control method is improved to improve wind energy utilization; on the other hand, an energy coordinated control strategy is proposed. The balance of energy supply and demand is realized, thus reducing the fluctuation of output voltage. Firstly, on the basis of analyzing the mathematical model of off-grid wind power generation, an unexpected speed control structure is derived. Considering the good adaptability of fuzzy control to nonlinear systems and the stability and speed of Pi control, a mountain climbing search algorithm based on fuzzy Pi is designed. The algorithm uses fuzzy logic to determine the reference search step size, then Pi adjusts the voltage closed-loop and tracks the reference search step size to realize the fast and effective maximum wind energy capture control. The stability of the method is analyzed by using Lyapnov theory. On the Simulink platform, the classical mountain climbing algorithm and the improved method are compared and analyzed. The results show that the search efficiency of the improved algorithm is improved by about 30%. Secondly, a coordinated energy control method is designed, which harmonizes the wind turbine, energy storage, unloading and load, realizes the balance of energy supply and demand, and stabilizes the output voltage. By analyzing the reason of the output voltage fluctuation, the system energy balance can be realized by stabilizing the DC bus voltage. According to the load requirement, the state of the energy storage system, the wind turbine switches between the three modes of maximum power tracking, constant power and limited removal. The energy storage form composed of super capacitor and battery is designed. Batteries buffer low frequency fluctuations, super capacitors buffer high frequency fluctuations. This method not only improves the energy utilization efficiency, but also reduces the battery charge and discharge times and prolongs the battery life. Thirdly, the design process of off-grid wind power system hardware circuit is described in detail, including design idea, principle explanation and parameter selection. The hardware includes main circuit, detection circuit, power cut in and LED lighting load. The main circuit converts fluctuating wind energy into power available to load. The detection circuit converts analog signals such as voltage and current into digital signals for DSP calculation. Under the condition of city electricity access or diesel power generation, when the wind power and battery supply is insufficient, the designed power supply will be automatically connected to the city electricity or diesel power generation to ensure the stable operation of the load. In this paper, the LED illumination is used as the load to design an efficient, low temperature human detection LED driving circuit. Fourthly, the DSP chip TMS320F2808 produced by Texas Instruments is taken as the control core, and the control strategy is realized digitally. In the process of software development, the concept of modular design is applied. First of all, control function partition, the same function of the unit as a module. Secondly, the related software is compiled according to the function of the module. Finally, a non-preemptive multi-task scheduling mode is designed to schedule each functional module. Fifth, the problems encountered in the debugging process and the solutions are analyzed. The overall software and hardware are tested, and the results verify the feasibility of the design.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TM614;TP273

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